Attachment theory describes the dynamics of long-term relationships between humans. However, ‘attachment theory is not formulated as a general theory of relationships. It addresses only a specific facet’ (Waters et al. 2005: 81): how human beings respond within relationships when hurt, separated from loved ones, or perceiving a threat. In infants, attachment as a motivational and behavioural system directs the child to seek proximity with a familiar caregiver when they are alarmed, with the expectation that they will receive protection and emotional support. Bowlby believed that the tendency for primate infants to develop attachments to familiar caregivers was the result of evolutionary pressures, since attachment behaviour would facilitate the infant’s survival in the face of dangers such as predation or exposure to the elements.
The most important tenet of attachment theory is that an infant needs to develop a relationship with at least one primary caregiver for the child’s successful social and emotional development, and in particular for learning how to effectively regulate their feelings. Fathers or any other individuals, are equally likely to become principal attachment figures if they provide most of the child care and related social interaction. In the presence of a sensitive and responsive caregiver, the infant will use the caregiver as a “safe base” from which to explore. It should be recognized that “even sensitive caregivers get it right only about 50 percent of the time. Their communications are either out of synch, or mismatched. There are times when parents feel tired or distracted. The telephone rings or there is breakfast to prepare. In other words, attuned interactions rupture quite frequently. But the hallmark of a sensitive caregiver is that the ruptures are managed and repaired.” 
Attachments between infants and caregivers form even if this caregiver is not sensitive and responsive in social interactions with them. This has important implications. Infants cannot exit unpredictable or insensitive caregiving relationships. Instead they must manage themselves as best they can within such relationships. Research by developmental psychologist Mary Ainsworth in the 1960s and 70s found that children will have different patterns of attachment depending primarily on how they experienced their early caregiving environment. Early patterns of attachment, in turn, shape – but do not determine - the individual's expectations in later relationships. Four different attachment classifications have been identified in children: secure attachment, anxious-ambivalent attachment, anxious-avoidant attachment, and disorganized attachment. Attachment theory has become the dominant theory used today in the study of infant and toddler behavior and in the fields of infant mental health, treatment of children, and related fields. In the 1980s, the theory was extended to attachment in adults.
- 1 Infant attachment
- 2 Attachment classification in children: The Strange Situation Protocol
- 3 Attachment patterns
- 4 Changes in attachment during childhood and adolescence
- 5 Attachment in adults
- 6 History
- 7 Biology of attachment
- 8 Practical applications
- 9 See also
- 10 Notes
- 11 References
- 12 Further reading
- 13 External links
Within attachment theory, attachment means 'a biological instinct in which proximity to an attachment figure is sought when the child senses or perceives threat or discomfort. Attachment behaviour anticipates a response by the attachment figure which will remove threat or discomfort’ Such bonds may be reciprocal between two adults, but between a child and a caregiver these bonds are based on the child's need for safety, security and protection, paramount in infancy and childhood. [Bowlby] begins by noting that organisms at different levels of the phylogenetic scale regulate instinctive behavior in distinct ways, ranging from primitive reflex-like "fixed action patterns" to complex plan hierarchies with subgoals and strong learning components. In the most complex organisms, instinctive behaviors may be "goal-corrected" with continual on-course adjustments (such as a bird of prey adjusting its flight to the movements of the prey). The concept of cybernetically controlled behavioral systems organized as plan hierarchies (Miller, Galanter, and Pribram, 1960) thus came to replace Freud's concept of drive and instinct. Such systems regulate behaviors in ways that need not be rigidly innate, but—depending on the organism—can adapt in greater or lesser degrees to changes in environmental circumstances, provided that these do not deviate too much from the organism's environment of evolutionary adaptedness. Such flexible organisms pay a price, however, because adaptable behavioral systems can more easily be subverted from their optimal path of development. For humans, Bowlby speculates, the environment of evolutionary adaptedness probably resembles that of present-day hunter-gatherer societies. for the purpose of survival, and, ultimately, genetic replication. Attachment theory is not an exhaustive description of human relationships, nor is it synonymous with love and affection, although these may indicate that bonds exist. Some infants direct attachment behaviour (proximity seeking) toward more than one attachment figure almost as soon as they start to show discrimination between caregivers; most come to do so during their second year. These figures are arranged hierarchically, with the principal attachment figure at the top. The set-goal of the attachment behavioural system is to maintain the accessibility and availability of the attachment figure. "Alarm" is the term used for activation of the attachment behavioural system caused by fear of danger. "Anxiety" is the anticipation or fear of being cut off from the attachment figure. If the figure is unavailable or unresponsive, separation distress occurs. In infants, physical separation can cause anxiety and anger, followed by sadness and despair. By age three or four, physical separation is no longer such a threat to the child's bond with the attachment figure. Threats to security in older children and adults arise from prolonged absence, breakdowns in communication, emotional unavailability, or signs of rejection or abandonment.
The attachment behavioural system serves to achieve or maintain close proximity to the attachment figure. Pre-attachment behaviours occur in the first six months of life. During the first phase (the first eight weeks), infants smile, babble, and cry to attract the attention of potential caregivers. Although infants of this age learn to discriminate between caregivers, these behaviours are directed at anyone in the vicinity. During the second phase (two to six months), the infant increasingly discriminates between familiar and unfamiliar adults, becoming more responsive toward the caregiver; following and clinging are added to the range of behaviours. Clear-cut attachment develops in the third phase, between the ages of six months and two years. The infant's behaviour toward the caregiver becomes organised on a goal-directed basis to achieve the conditions that make it feel secure. By the end of the first year, the infant is able to display a range of attachment behaviours designed to maintain proximity. These manifest as protesting the caregiver's departure, greeting the caregiver's return, clinging when frightened, and following when able. With the development of locomotion, the infant begins to use the caregiver or caregivers as a “safe base” from which to explore. Infant exploration is greater when the caregiver is present because the infant's attachment system is relaxed and it is free to explore. If the caregiver is inaccessible or unresponsive, attachment behaviour is more strongly exhibited. Anxiety, fear, illness, and fatigue will cause a child to increase attachment behaviours. After the second year, as the child begins to see the caregiver as an independent person, a more complex and goal-corrected partnership is formed. Children begin to notice others' goals and feelings and plan their actions accordingly. For example, whereas babies cry because of pain, two-year-olds cry to summon their caregiver, and if that does not work, cry louder, shout, or follow.
Common attachment behaviours and emotions, displayed in most social primates including humans, are adaptive. The long-term evolution of these species has involved selection for social behaviors that make individual or group survival more likely. The commonly observed attachment behaviour of toddlers staying near familiar people would have had safety advantages in the environment of early adaptation, and has similar advantages today. Bowlby saw the environment of early adaptation as similar to current hunter-gatherer societies. There is a survival advantage in the capacity to sense possibly dangerous conditions such as unfamiliarity, being alone, or rapid approach. According to Bowlby, proximity-seeking to the attachment figure in the face of threat is the "set-goal" of the attachment behavioural system.
Bowlby's original account of a sensitivity period during which attachments can form of between six months and two to three years has been modified by later researchers. These researchers have shown that there is indeed a sensitive period during which attachments will form if possible, but the time frame is broader and the effect less fixed and irreversible than first proposed. With further research, authors discussing attachment theory have come to appreciate that social development is affected by later as well as earlier relationships. Early steps in attachment take place most easily if the infant has one caregiver, or the occasional care of a small number of other people. According to Bowlby, almost from the first many children have more than one figure toward whom they direct attachment behaviour. These figures are not treated alike; there is a strong bias for a child to direct attachment behaviour mainly toward one particular person. Bowlby used the term "monotropy" to describe this bias. Researchers and theorists have abandoned this concept insofar as it may be taken to mean that the relationship with the special figure differs qualitatively from that of other figures. Rather, current thinking postulates definite hierarchies of relationships.
Early experiences with caregivers gradually give rise to a system of thoughts, memories, beliefs, expectations, emotions, and behaviours about the self and others. This system, called the "internal working model of social relationships", continues to develop with time and experience. Internal models regulate, interpret, and predict attachment-related behaviour in the self and the attachment figure. As they develop in line with environmental and developmental changes, they incorporate the capacity to reflect and communicate about past and future attachment relationships. They enable the child to handle new types of social interactions; knowing, for example, that an infant should be treated differently from an older child, or that interactions with teachers and parents share characteristics. This internal working model continues to develop through adulthood, helping cope with friendships, marriage, and parenthood, all of which involve different behaviours and feelings. The development of attachment is a transactional process. Specific attachment behaviours begin with predictable, apparently innate, behaviours in infancy. They change with age in ways that are determined partly by experiences and partly by situational factors. As attachment behaviours change with age, they do so in ways shaped by relationships. A child's behaviour when reunited with a caregiver is determined not only by how the caregiver has treated the child before, but on the history of effects the child has had on the caregiver.
Attachment classification in children: The Strange Situation Protocol
The most common and empirically supported method for assessing attachment in infants (12months-20months) is the Strange Situation Protocol, developed by Mary Ainsworth as a result of her careful in-depth observations of infants with their mothers in Uganda(see below). The Strange Situation Protocol is a research, not a diagnostic, tool and the resulting attachment classifications are not 'clinical diagnoses.' While the procedure may be used to supplement clinical impressions, the resulting classifications should not be confused with the clinically diagnosed 'Reactive Attachment Disorder (RAD).' The clinical concept of RAD differs in a number of fundamental ways from the theory and research driven attachment classifications based on the Strange Situation Procedure. The idea that insecure attachments are synonymous with RAD is, in fact, not accurate and leads to ambiguity when formally discussing attachment theory as it has evolved in the research literature. This is not to suggest that the concept of RAD is without merit, but rather that the clinical and research conceptualizations of insecure attachment and attachment disorder are not synonymous.
The 'Strange Situation' is a laboratory procedure used to assess infant patterns of attachment to their caregiver. In the procedure, the mother and infant are placed in an unfamiliar playroom equipped with toys while a researcher observes/records the procedure through a one-way mirror. The procedure consists of eight sequential episodes in which the child experiences both separation from and reunion with the mother as well as the presence of an unfamiliar stranger. The protocol is conducted in the following format unless modifications are otherwise noted by a particular researcher:
- Episode 1: Mother (or other familiar caregiver), Baby, Experimenter (30 seconds)
- Episode 2: Mother, Baby (3 mins)
- Episode 3: Mother, Baby, Stranger (3 mins or less)
- Episode 4: Stranger, Baby (3 mins)
- Episode 5: Mother, Baby (3 mins)
- Episode 6: Baby Alone (3 mins or less)
- Episode 7: Stranger, Baby (3 mins or less)
- Episode 8: Mother, Baby (3 mins)
Mainly on the basis of their reunion behaviours (although other behaviors are taken into account) in the Strange Situation Paradigm (Ainsworth et al., 1978; see below), infants can be categorized into three 'organized' attachment categories: Secure (Group B); Avoidant (Group A); and Anxious/Resistant (Group C). There are subclassifications for each group (see below). A fourth category, termed Disorganized (D), can also be assigned to an infant assessed in the Strange Situation although a primary 'organized' classification is always given for an infant judged to be disorganized. Each of these groups reflects a different kind of attachment relationship with the mother. A child may have a different type of attachment to each parent as well as to unrelated caregivers. Attachment style is thus not so much a part of the child's thinking, but is characteristic of a specific relationship. However, after about age five children tend to exhibits one primary consistent pattern of attachment in relationships.
The pattern the child develops after age five demonstrates the specific parenting styles used during the developmental stages within the child. These attachment patterns are associated with behavioral patterns and can help further predict a child's future personality.
“The strength of a child’s attachment behaviour in a given circumstance does not indicate the ‘strength’ of the attachment bond. Some insecure children will routinely display very pronounced attachment behaviours, while many secure children find that there is no great need to engage in either intense or frequent shows of attachment behaviour”.
A toddler who is securely attached to its parent (or other familiar caregiver) will explore freely while the caregiver is present, typically engages with strangers, is often visibly upset when the caregiver departs, and is generally happy to see the caregiver return. The extent of exploration and of distress are affected by the child's temperamental make-up and by situational factors as well as by attachment status, however. A child's attachment is largely influenced by their primary caregiver's sensitivity to their needs. Parents who consistently (or almost always) respond to their child's needs will create securely attached children. Such children are certain that their parents will be responsive to their needs and communications.
In the traditional Ainsworth et al. (1978) coding of the Strange Situation, secure infants are denoted as "Group B" infants and they are further subclassified as B1, B2, B3, and B4. Although these subgroupings refer to different stylistic responses to the comings and goings of the caregiver, they were not given specific labels by Ainsworth and colleagues, although their descriptive behaviors led others (including students of Ainsworth) to devise a relatively 'loose' terminology for these subgroups. B1's have been referred to as 'secure-reserved', B2's as 'secure-inhibited', B3's as 'secure-balanced,' and B4's as 'secure-reactive.' In academic publications however, the classification of infants (if subgroups are denoted) is typically simply "B1" or "B2" although more theoretical and review-oriented papers surrounding attachment theory may use the above terminology.
Securely attached children are best able to explore when they have the knowledge of a secure base to return to in times of need. When assistance is given, this bolsters the sense of security and also, assuming the parent's assistance is helpful, educates the child in how to cope with the same problem in the future. Therefore, secure attachment can be seen as the most adaptive attachment style. According to some psychological researchers, a child becomes securely attached when the parent is available and able to meet the needs of the child in a responsive and appropriate manner. At infancy and early childhood, if parents are caring and attentive towards their children, those children will be more prone to secure attachment.
Anxious-resistant insecure attachment
Anxious-resistant insecure attachment is also called ambivalent attachment. In general, a child with an anxious-resistant attachment style will typically explore little (in the Strange Situation) and is often wary of strangers, even when the parent is present. When the mother departs, the child is often highly distressed. The child is generally ambivalent when she returns. The Anxious-Ambivalent/Resistant strategy is a response to unpredictably responsive caregiving, and that the displays of anger or helplessness towards the caregiver on reunion can be regarded as a conditional strategy for maintaining the availability of the caregiver by preemptively taking control of the interaction.
The C1 subtype is coded when:
"...resistant behavior is particularly conspicuous. The mixture of seeking and yet resisting contact and interaction has an unmistakeably angry quality and indeed an angry tone may characterize behavior in the preseparation episodes..."
The C2 subtype is coded when:
"Perhaps the most conspicuous characteristic of C2 infants is their passivity. Their exploratory behavior is limited throughout the SS and their interactive behaviors are relatively lacking in active initiation. Nevertheless, in the reunion episodes they obviously want proximity to and contact with their mothers, even though they tend to use signalling rather than active approach, and protest against being put down rather than actively resisting release...In general the C2 baby is not as conspicuously angry as the C1 baby."
Anxious-avoidant insecure attachment
A child with the anxious-avoidant insecure attachment style will avoid or ignore the caregiver - showing little emotion when the caregiver departs or returns. The child will not explore very much regardless of who is there. Infants classified as anxious-avoidant (A) represented a puzzle in the early 1970s. They did not exhibit distress on separation, and either ignored the caregiver on their return (A1 subtype) or showed some tendency to approach together with some tendency to ignore or turn away from the caregiver (A2 subtype). Ainsworth and Bell theorised that the apparently unruffled behaviour of the avoidant infants is in fact as a mask for distress, a hypothesis later evidenced through studies of the heart-rate of avoidant infants.
Infants are depicted as anxious-avoidant insecure when there is:
"...conspicuous avoidance of the mother in the reunion episodes which is likely to consist of ignoring her altogether, although there may be some pointed looking away, turning away, or moving away...If there is a greeting when the mother enters, it tends to be a mere look or a smile...Either the baby does not approach his mother upon reunion, or they approach in 'abortive' fashions with the baby going past the mother, or it tends to only occur after much coaxing...If picked up, the baby shows little or no contact-maintaining behavior; he tends not to cuddle in; he looks away and he may squirm to get down."
Ainsworth’s narrative records showed that infants avoided the caregiver in the stressful Strange Situation Procedure when they had a history of experiencing rebuff of attachment behaviour. The child's needs are frequently not met and the child comes to believe that communication of needs has no influence on the caregiver. Ainsworth's student Mary Main theorised that avoidant behaviour in the Strange Situational Procedure should be regarded as ‘a conditional strategy, which paradoxically permits whatever proximity is possible under conditions of maternal rejection’ by de-emphasising attachment needs. Main proposed that avoidance has two functions for an infant whose caregiver is consistently unresponsive to their needs. Firstly, avoidant behaviour allows the infant to maintain a conditional proximity with the caregiver: close enough to maintain protection, but distant enough to avoid rebuff. Secondly, the cognitive processes organising avoidant behaviour could help direct attention away from the unfulfilled desire for closeness with the caregiver - avoiding a situation in which the child is overwhelmed with emotion ('disorganised distress'), and therefore unable to maintain control of themselves and achieve even conditional proximity.
Ainsworth herself was the first to find difficulties in fitting all infant behaviour into the three classifications used in her Baltimore study. Ainsworth and colleagues sometimes observed ‘tense movements such as hunching the shoulders, putting the hands behind the neck and tensely cocking the head, and so on. It was our clear impression that such tension movements signified stress, both because they tended to occur chiefly in the separation episodes and because they tended to be prodromal to crying. Indeed, our hypothesis is that they occur when a child is attempting to control crying, for they tend to vanish if and when crying breaks through’. Such observations also appeared in the doctoral theses of Ainsworth's students. Crittenden, for example, noted that one abused infant in her doctoral sample was classed as secure (B) by her undergraduate coders because her strange situation behavior was “without either avoidance or ambivalence, she did show stress-related stereotypic headcocking throughout the strange situation. This pervasive behavior, however, was the only clue to the extent of her stress”.
Drawing on records of behaviours discrepant with the A,B and C classifications, a fourth classification was added by Ainsworth's colleague Mary Main. In the Strange Situation, the attachment system is expected to be activated by the departure and return of the caregiver. If the behaviour of the infant does not appear to the observer to be coordinated in a smooth way across episodes to achieve either proximity or some relative proximity with the caregiver, then it is considered 'disorganised' as it indicates a disruption or flooding of the attachment system (e.g. by fear). Infant behaviours in the Strange Situation Protocol coded as disorganised/disoriented include overt displays of fear; contradictory behaviours or affects occurring simultaneously or sequentially; stereotypic, asymmetric, misdirected or jerky movements; or freezing and apparent dissociation. Lyons-Ruth has urged, however, that it should be wider 'recognized that 52% of disorganized infants continue to approach the caregiver, seek comfort, and cease their distress without clear ambivalent or avoidant behavior.' 
There is ‘rapidly growing interest in disorganized attachment’ from clinicians and policy-makers as well as researchers. Yet the Disorganized/disoriented attachment (D) classification has been criticised by some for being too encompassing. In 1990, Ainsworth put in print her blessing for the new ‘D’ classification, though she urged that the addition be regarded as ‘open-ended, in the sense that subcategories may be distinguished’, as she worried that the D classification might be too encompassing and might treat too many different forms of behaviour as if they were the same thing. Indeed, the D classification puts together infants who use a somewhat disrupted secure (B) strategy with those who seem hopeless and show little attachment behaviour; it also puts together infants who run to hide when they see their caregiver in the same classification as those who show an avoidant (A) strategy on the first reunion and then an ambivalent-resistant (C) strategy on the second reunion. Perhaps responding to such concerns, George and Solomon have divided among indices of Disorganized/disoriented attachment (D) in the Strange Situation, treating some of the behaviours as a ‘strategy of desperation’ and others as evidence that the attachment system has been flooded (e.g. by fear, or anger). Crittenden also argues that some behaviour classified as Disorganized/disoriented can be regarded as more 'emergency' versions of the avoidant and/or ambivalent/resistant strategies, and function to maintain the protective availability of the caregiver to some degree. Sroufe et al. have agreed that ‘even disorganised attachment behaviour (simultaneous approach-avoidance; freezing, etc.) enables a degree of proximity in the face of a frightening or unfathomable parent’. However, 'the presumption that many indices of “disorganisation” are aspects of organised patterns does not preclude acceptance of the notion of disorganisation, especially in cases where the complexity and dangerousness of the threat are beyond children’s capacity for response’. For example, ‘Children placed in care, especially more than once, often have intrusions. In videos of the Strange Situation Procedure, they tend to occur when a rejected/neglected child approaches the stranger in an intrusion of desire for comfort, then loses muscular control and falls to the floor, overwhelmed by the intruding fear of the unknown, potentially dangerous, strange person’.
Main and Hesse found that most of the mothers of these children had suffered major losses or other trauma shortly before or after the birth of the infant and had reacted by becoming severely depressed. In fact, 56% of mothers who had lost a parent by death before they completed high school subsequently had children with disorganized attachments. Subsequently studies, whilst emphasising the potential importance of unresolved loss, have qualified these findings. For example, Solomon and George found that unresolved loss in the mother tended to be associated with disorganised attachment in their infant primarily when they had also experienced an unresolved trauma in their life prior to the loss.
Later patterns and the Dynamic-Maturational Model
Techniques have been developed to allow verbal ascertainment of the child's state of mind with respect to attachment. An example is the "stem story", in which a child is given the beginning of a story that raises attachment issues and asked to complete it. For older children, adolescents and adults, semi-structured interviews are used in which the manner of relaying content may be as significant as the content itself. However, there are no substantially validated measures of attachment for middle childhood or early adolescence (approximately 7 to 13 years of age). Some studies of older children have identified further attachment classifications. Main and Cassidy observed that disorganized behavior in infancy can develop into a child using caregiving-controlling or punitive behaviour in order to manage a helpless or dangerously unpredictable caregiver. In these cases, the child's behaviour is organised, but the behaviour is treated by researchers as a form of 'disorganization' (D) since the hierarchy in the family is no longer organised according to parenting authority.
Patricia McKinsey Crittenden has elaborated classifications of further forms of avoidant and ambivalent attachment behaviour. These include the caregiving and punitive behaviours also identified by Main and Cassidy (termed A3 and C3 respectively), but also other patterns such as compulsive compliance with the wishes of a threatening parent (A4).
Crittenden's ideas developed from Bowlby's proposal that ‘given certain adverse circumstances during childhood, the selective exclusion of information of certain sorts may be adaptive. Yet, when during adolescence and adult the situation changes, the persistent exclusion of the same forms of information may become maladaptive’.
Crittenden proposed that the basic components of human experience of danger are two kinds of information:
1. ‘Affective information’ – the emotions provoked by the potential for danger, such as anger or fear. Crittenden terms this ‘affective information’. In childhood this information would include emotions provoked by the unexplained absence of an attachment figure. Where an infant is faced with insensitive or rejecting parenting, one strategy for maintaining the availability of their attachment figure is to try to exclude from consciousness or from expressed behaviour any emotional information that might result in rejection.
2. Causal or other sequentially-ordered knowledge about the potential for safety or danger. In childhood this would include knowledge regarding the behaviours that indicate an attachment figure’s availability as a secure haven. If knowledge regarding the behaviours that indicate an attachment figure’s availability as a secure haven is subject to segregation, then the infant can try to keep the attention of their caregiver through clingy or aggressive behaviour, or alternating combinations of the two. Such behaviour may increase the availability of an attachment figure who otherwise displays inconsistent or misleading responses to the infant’s attachment behaviours, suggesting the unreliability of protection and safety.
Crittenden proposes that both kinds of information can be split off from consciousness or behavioural expression as a ‘strategy’ to maintain the availability of an attachment figure: 'Type A strategies were hypothesized to be based on reducing perception of threat to reduce the disposition to respond. Type C was hypothesized to be based on heightening perception of threat to increase the disposition to respond'  Type A strategies split off emotional information about feeling threatened and type C strategies split off temporally-sequenced knowledge about how and why the attachment figure is available. By contrast, type B strategies effectively utilise both kinds of information without much distortion. For example: a toddler may have come to depend upon a type C strategy of tantrums in working to maintain the availability of an attachment figure whose inconsistent availability has led the child to distrust or distort causal information about their apparent behaviour. This may lead their attachment figure to get a clearer grasp on their needs and the appropriate response to their attachment behaviours. Experiencing more reliable and predictable information about the availability of their attachment figure, the toddler then no longer needs to use coercive behaviours with the goal of maintaining their caregiver’s availability and can develop a secure attachment to their caregiver since they trust that their needs and communications will be heeded.
Significance of patterns
Research based on data from longitudinal studies, such as the National Institute of Child Health and Human Development Study of Early Child Care and the Minnesota Study of Risk and Adaption from Birth to Adulthood, and from cross-sectional studies, consistently shows associations between early attachment classifications and peer relationships as to both quantity and quality. Lyons-Ruth, for example, found that 'for each additional withdrawing behavior displayed by mothers in relation to their infant’s attachment cues in the Strange Situation Procedure, the likelihood of clinical referral by service providers was increased by 50%.' There is an extensive body of research demonstrating a significant association between attachment organizations and children's functioning across multiple domains. Early insecure attachment does not necessarily predict difficulties, but it is a liability for the child, particularly if similar parental behaviours continue throughout childhood. Compared to that of securely attached children, the adjustment of insecure children in many spheres of life is not as soundly based, putting their future relationships in jeopardy. Although the link is not fully established by research and there are other influences besides attachment, secure infants are more likely to become socially competent than their insecure peers. Relationships formed with peers influence the acquisition of social skills, intellectual development and the formation of social identity. Classification of children's peer status (popular, neglected or rejected) has been found to predict subsequent adjustment. Insecure children, particularly avoidant children, are especially vulnerable to family risk. Their social and behavioural problems increase or decline with deterioration or improvement in parenting. However, an early secure attachment appears to have a lasting protective function. As with attachment to parental figures, subsequent experiences may alter the course of development. Studies have suggested that infants with a high-risk for Autism Spectrum Disorders (ASD) may express attachment security differently from infants with a low-risk for ASD. Behavioral problems and social competence in insecure children increase or decline with deterioration or improvement in quality of parenting and the degree of risk in the family environment. Some authors have questioned the idea that a taxonomy of categories representing a qualitative difference in attachment relationships can be developed. Examination of data from 1,139 15-month-olds showed that variation in attachment patterns was continuous rather than grouped. This criticism introduces important questions for attachment typologies and the mechanisms behind apparent types. However, it has relatively little relevance for attachment theory itself, which "neither requires nor predicts discrete patterns of attachment". There is some evidence that gender differences in attachment patterns of adaptive significance begin to emerge in middle childhood. Insecure attachment and early psychosocial stress indicate the presence of environmental risk (for example poverty, mental illness, instability, minority status, violence). Environmental risk can cause insecure attachment, while also favouring the development of strategies for earlier reproduction. Different reproductive strategies have different adaptive values for males and females: Insecure males tend to adopt avoidant strategies, whereas insecure females tend to adopt anxious/ambivalent strategies, unless they are in a very high risk environment. Adrenarche is proposed as the endocrine mechanism underlying the reorganization of insecure attachment in middle childhood.
Changes in attachment during childhood and adolescence
Age, cognitive growth, and continued social experience advance the development and complexity of the internal working model. Attachment-related behaviours lose some characteristics typical of the infant-toddler period and take on age-related tendencies. The preschool period involves the use of negotiation and bargaining. For example, four-year-olds are not distressed by separation if they and their caregiver have already negotiated a shared plan for the separation and reunion.
Ideally, these social skills become incorporated into the internal working model to be used with other children and later with adult peers. As children move into the school years at about six years old, most develop a goal-corrected partnership with parents, in which each partner is willing to compromise in order to maintain a gratifying relationship. By middle childhood, the goal of the attachment behavioural system has changed from proximity to the attachment figure to availability. Generally, a child is content with longer separations, provided contact—or the possibility of physically reuniting, if needed—is available. Attachment behaviours such as clinging and following decline and self-reliance increases. By middle childhood (ages 7–11), there may be a shift toward mutual coregulation of secure-base contact in which caregiver and child negotiate methods of maintaining communication and supervision as the child moves toward a greater degree of independence.
Attachment in adults
Attachment theory was extended to adult romantic relationships in the late 1980s by Cindy Hazan and Phillip Shaver. Four styles of attachment have been identified in adults: secure, anxious-preoccupied, dismissive-avoidant and fearful-avoidant. These roughly correspond to infant classifications: secure, insecure-ambivalent, insecure-avoidant and disorganized/disoriented.
Securely attached adults tend to have positive views of themselves, their partners and their relationships. They feel comfortable with intimacy and independence, balancing the two. Anxious-preoccupied adults seek high levels of intimacy, approval and responsiveness from partners, becoming overly dependent. They tend to be less trusting, have less positive views about themselves and their partners, and may exhibit high levels of emotional expressiveness, worry and impulsiveness in their relationships. Dismissive-avoidant adults desire a high level of independence, often appearing to avoid attachment altogether. They view themselves as self-sufficient, invulnerable to attachment feelings and not needing close relationships. They tend to suppress their feelings, dealing with rejection by distancing themselves from partners of whom they often have a poor opinion. Fearful-avoidant adults have mixed feelings about close relationships, both desiring and feeling uncomfortable with emotional closeness. They tend to mistrust their partners and view themselves as unworthy. Like dismissive-avoidant adults, fearful-avoidant adults tend to seek less intimacy, suppressing their feelings.
Two main aspects of adult attachment have been studied. The organisation and stability of the mental working models that underlie the attachment styles is explored by social psychologists interested in romantic attachment. Developmental psychologists interested in the individual's state of mind with respect to attachment generally explore how attachment functions in relationship dynamics and impacts relationship outcomes. The organisation of mental working models is more stable while the individual's state of mind with respect to attachment fluctuates more. Some authors have suggested that adults do not hold a single set of working models. Instead, on one level they have a set of rules and assumptions about attachment relationships in general. On another level they hold information about specific relationships or relationship events. Information at different levels need not be consistent. Individuals can therefore hold different internal working models for different relationships.
There are a number of different measures of adult attachment, the most common being self-report questionnaires and coded interviews based on the Adult Attachment Interview. The various measures were developed primarily as research tools, for different purposes and addressing different domains, for example romantic relationships, parental relationships or peer relationships. Some classify an adult's state of mind with respect to attachment and attachment patterns by reference to childhood experiences, while others assess relationship behaviours and security regarding parents and peers.
The early thinking of the object relations school of psychoanalysis, particularly Melanie Klein, influenced Bowlby. However, he profoundly disagreed with the prevalent psychoanalytic belief that infants' responses relate to their internal fantasy life rather than real-life events. As Bowlby formulated his concepts, he was influenced by case studies on disturbed and delinquent children, such as those of William Goldfarb published in 1943 and 1945.
Bowlby's contemporary René Spitz observed separated children's grief, proposing that "psychotoxic" results were brought about by inappropriate experiences of early care.
During World War II a "real life experiment" took place when thousands of children were evacuated from the cities being bombed by the Nazis. The grief response, especially of the youngest children, provided clear evidence of loss of attachment to childcare givers and their supervisors, including Anna Freud. This set the stage for developments after the war.
A strong influence was the work of social worker and psychoanalyst James Robertson who filmed the effects of separation on children in hospital. He and Bowlby collaborated in making the 1952 documentary film A Two-Year Old Goes to the Hospital which was instrumental in a campaign to alter hospital restrictions on visits by parents.
In his 1951 monograph for the World Health Organisation, Maternal Care and Mental Health, Bowlby put forward the hypothesis that "the infant and young child should experience a warm, intimate, and continuous relationship with his mother in which both find satisfaction and enjoyment", the lack of which may have significant and irreversible mental health consequences. This was also published as Child Care and the Growth of Love for public consumption. The central proposition was influential but highly controversial. At the time there was limited empirical data and no comprehensive theory to account for such a conclusion. Nevertheless, Bowlby's theory sparked considerable interest in the nature of early relationships, giving a strong impetus to, (in the words of Mary Ainsworth), a "great body of research" in an extremely difficult, complex area. Bowlby's work (and Robertson's films) caused a virtual revolution in hospital visiting by parents, hospital provision for children's play, educational and social needs and the use of residential nurseries. Over time, orphanages were abandoned in favour of foster care or family-style homes in most developed countries.
Following the publication of Maternal Care and Mental Health, Bowlby sought new understanding from the fields of evolutionary biology, ethology, developmental psychology, cognitive science and control systems theory. He formulated the innovative proposition that mechanisms underlying an infant's emotional tie to the caregiver(s) emerged as a result of evolutionary pressure. He set out to develop a theory of motivation and behaviour control built on science rather than Freud's psychic energy model. Bowlby argued that with attachment theory he had made good the "deficiencies of the data and the lack of theory to link alleged cause and effect" of Maternal Care and Mental Health.
Bowlby's attention was first drawn to ethology when he read Konrad Lorenz's 1952 publication in draft form (although Lorenz had published earlier work). Other important influences were ethologists Nikolaas Tinbergen and Robert Hinde. Bowlby subsequently collaborated with Hinde. In 1953 Bowlby stated "the time is ripe for a unification of psychoanalytic concepts with those of ethology, and to pursue the rich vein of research which this union suggests". Konrad Lorenz had examined the phenomenon of "imprinting", a behaviour characteristic of some birds and mammals which involves rapid learning of recognition by the young, of a conspecific or comparable object. After recognition comes a tendency to follow.
The learning is possible only within a limited age range known as a critical period. Bowlby's concepts included the idea that attachment involved learning from experience during a limited age period, influenced by adult behaviour. He did not apply the imprinting concept in its entirety to human attachment. However, he considered that attachment behaviour was best explained as instinctive, combined with the effect of experience, stressing the readiness the child brings to social interactions. Over time it became apparent there were more differences than similarities between attachment theory and imprinting so the analogy was dropped.
Ethologists expressed concern about the adequacy of some research on which attachment theory was based, particularly the generalisation to humans from animal studies. Schur, discussing Bowlby's use of ethological concepts (pre-1960) commented that concepts used in attachment theory had not kept up with changes in ethology itself. Ethologists and others writing in the 1960s and 1970s questioned and expanded the types of behaviour used as indications of attachment. Observational studies of young children in natural settings provided other behaviours that might indicate attachment; for example, staying within a predictable distance of the mother without effort on her part and picking up small objects, bringing them to the mother but not to others. Although ethologists tended to be in agreement with Bowlby, they pressed for more data, objecting to psychologists writing as if there were an "entity which is 'attachment', existing over and above the observable measures." Robert Hinde considered "attachment behaviour system" to be an appropriate term which did not offer the same problems "because it refers to postulated control systems that determine the relations between different kinds of behaviour."
Psychoanalytic concepts influenced Bowlby's view of attachment, in particular, the observations by Anna Freud and Dorothy Burlingham of young children separated from familiar caregivers during World War II. However, Bowlby rejected psychoanalytical explanations for early infant bonds including "drive theory" in which the motivation for attachment derives from gratification of hunger and libidinal drives. He called this the "cupboard-love" theory of relationships. In his view it failed to see attachment as a psychological bond in its own right rather than an instinct derived from feeding or sexuality. Based on ideas of primary attachment and Neo-Darwinism, Bowlby identified what he saw as fundamental flaws in psychoanalysis: the overemphasis of internal dangers rather than external threat, and the view of the development of personality via linear phases with regression to fixed points accounting for psychological distress. He instead posited that several lines of development were possible, the outcome of which depended on the interaction between the organism and the environment. In attachment this would mean that although a developing child has a propensity to form attachments, the nature of those attachments depends on the environment to which the child is exposed.
From early in the development of attachment theory there was criticism of the theory's lack of congruence with various branches of psychoanalysis. Bowlby's decisions left him open to criticism from well-established thinkers working on similar problems.
Internal working model
Bowlby adopted the important concept of the internal working model of social relationships from the work of the philosopher Kenneth Craik. Craik had noted the adaptiveness of the ability of thought to predict events. He stressed the survival value of and natural selection for this ability. According to Craik, prediction occurs when a "small-scale model" consisting of brain events is used to represent not only the external environment, but the individual's own possible actions. This model allows a person to try out alternatives mentally, using knowledge of the past in responding to the present and future. At about the same time Bowlby was applying Craik's ideas to attachment, other psychologists were applying these concepts to adult perception and cognition.
An infant's internal working model is organized around the accessibility and responsiveness of his or her caregiver. Each organization is developed in response to the infant's experience of the outcomes of his or her proximity seeking behaviors. If the caregiver is accepting of these proximity seeking behaviors and grants access, the infant develops a secure organization; if the caregiver consistently denies the infant access, an avoidant organization develops; if the caregiver inconsistently grants access, an ambivalent organization develops.
In the 1970s, problems with viewing attachment as a trait (stable characteristic of an individual) rather than as a type of behaviour with organising functions and outcomes, led some authors to the conclusion that attachment behaviours were best understood in terms of their functions in the child's life. This way of thinking saw the secure base concept as central to attachment theory's logic, coherence, and status as an organizational construct. Following this argument, the assumption that attachment is expressed identically in all humans cross-culturally was examined. The research showed that though there were cultural differences, the three basic patterns, secure, avoidant and ambivalent, can be found in every culture in which studies have been undertaken, even where communal sleeping arrangements are the norm.
Selection of the secure pattern is found in the majority of children across cultures studied. This follows logically from the fact that attachment theory provides for infants to adapt to changes in the environment, selecting optimal behavioural strategies. How attachment is expressed shows cultural variations which need to be ascertained before studies can be undertaken; for example Gusii infants are greeted with a handshake rather than a hug. Securely attached Gusii infants anticipate and seek this contact. There are also differences in the distribution of insecure patterns based on cultural differences in child-rearing practices.
The biggest challenge to the notion of the universality of attachment theory came from studies conducted in Japan where the concept of amae plays a prominent role in describing family relationships. Arguments revolved around the appropriateness of the use of the Strange Situation procedure where amae is practiced. Ultimately research tended to confirm the universality hypothesis of attachment theory. Most recently a 2007 study conducted in Sapporo in Japan found attachment distributions consistent with global norms using the six-year Main and Cassidy scoring system for attachment classification.
Critics in the 1990s such as J. R. Harris, Steven Pinker and Jerome Kagan were generally concerned with the concept of infant determinism (nature versus nurture), stressing the effects of later experience on personality. Building on the work on temperament of Stella Chess, Kagan rejected almost every assumption on which attachment theory etiology was based. He argued that heredity was far more important than the transient effects of early environment. For example a child with an inherently difficult temperament would not elicit sensitive behavioural responses from a caregiver. The debate spawned considerable research and analysis of data from the growing number of longitudinal studies. Subsequent research has not borne out Kagan's argument, broadly demonstrating that it is the caregiver's behaviours that form the child's attachment style, although how this style is expressed may differ with temperament. Harris and Pinker put forward the notion that the influence of parents had been much exaggerated, arguing that socialisation took place primarily in peer groups. H. Rudolph Schaffer concluded that parents and peers had different functions, fulfilling distinctive roles in children's development.
Psychoanalyst/psychologists Peter Fonagy and Mary Target have attempted to bring attachment theory and psychoanalysis into a closer relationship through cognitive science as mentalization. Mentalization, or theory of mind, is the capacity of human beings to guess with some accuracy what thoughts, emotions and intentions lie behind behaviours as subtle as facial expression. This connection between theory of mind and the internal working model may open new areas of study, leading to alterations in attachment theory. Since the late 1980s, there has been a developing rapprochement between attachment theory and psychoanalysis, based on common ground as elaborated by attachment theorists and researchers, and a change in what psychoanalysts consider to be central to psychoanalysis. Object relations models which emphasise the autonomous need for a relationship have become dominant and are linked to a growing recognition within psychoanalysis of the importance of infant development in the context of relationships and internalised representations. Psychoanalysis has recognised the formative nature of a childs early environment including the issue of childhood trauma. A psychoanalytically based exploration of the attachment system and an accompanying clinical approach has emerged together with a recognition of the need for measurement of outcomes of interventions.
One focus of attachment research has been the difficulties of children whose attachment history was poor, including those with extensive non-parental child care experiences. Concern with the effects of child care was intense during the so-called "day care wars" of the late 20th century, during which some authors stressed the deleterious effects of day care. As a result of this controversy, training of child care professionals has come to stress attachment issues, including the need for relationship-building by the assignment of a child to a specific carer. Although only high-quality child care settings are likely to provide this, more infants in child care receive attachment-friendly care than in the past. A natural experiment permitted extensive study of attachment issues as researchers followed thousands of Romanian orphans adopted into Western families after the end of the Nicolae Ceauşescu regime. The English and Romanian Adoptees Study Team, led by Michael Rutter, followed some of the children into their teens, attempting to unravel the effects of poor attachment, adoption, new relationships, physical problems and medical issues associated with their early lives. Studies of these adoptees, whose initial conditions were shocking, yielded reason for optimism as many of the children developed quite well. Researchers noted that separation from familiar people is only one of many factors that help to determine the quality of development. Although higher rates of atypical insecure attachment patterns were found compared to native-born or early-adopted samples, 70% of later-adopted children exhibited no marked or severe attachment disorder behaviours.
Authors considering attachment in non-Western cultures have noted the connection of attachment theory with Western family and child care patterns characteristic of Bowlby's time. As children's experience of care changes, so may attachment-related experiences. For example, changes in attitudes toward female sexuality have greatly increased the numbers of children living with their never-married mothers or being cared for outside the home while the mothers work. This social change has made it more difficult for childless people to adopt infants in their own countries. There has been an increase in the number of older-child adoptions and adoptions from third-world sources in first-world countries. Adoptions and births to same-sex couples have increased in number and gained legal protection, compared to their status in Bowlby's time. Issues have been raised to the effect that the dyadic model characteristic of attachment theory cannot address the complexity of real-life social experiences, as infants often have multiple relationships within the family and in child care settings. It is suggested these multiple relationships influence one another reciprocally, at least within a family.
Principles of attachment theory have been used to explain adult social behaviours, including mating, social dominance and hierarchical power structures, in-group identification, group coalitions, and negotiation of reciprocity and justice. Those explanations have been used to design parental care training, and have been particularly successful in the design of child abuse prevention programmes.
While a wide variety of studies have upheld the basic tenets of attachment theory, research has been inconclusive as to whether self-reported early attachment and later depression are demonstrably related.
Biology of attachment
In addition to longitudinal studies, there has been psychophysiological research on the biology of attachment. Research has begun to include neural development behaviour genetics and temperament concepts. Generally, temperament and attachment constitute separate developmental domains, but aspects of both contribute to a range of interpersonal and intrapersonal developmental outcomes. Some types of temperament may make some individuals susceptible to the stress of unpredictable or hostile relationships with caregivers in the early years. In the absence of available and responsive caregivers it appears that some children are particularly vulnerable to developing attachment disorders.
In psychophysiological research on attachment, the two main areas studied have been autonomic responses, such as heart rate or respiration, and the activity of the hypothalamic–pituitary–adrenal axis. Infants' physiological responses have been measured during the Strange Situation procedure looking at individual differences in infant temperament and the extent to which attachment acts as a moderator. There is some evidence that the quality of caregiving shapes the development of the neurological systems which regulate stress.
Another issue is the role of inherited genetic factors in shaping attachments: for example one type of polymorphism of the gene coding for the D2 dopamine receptor has been linked to anxious attachment and another in the gene for the 5-HT2A serotonin receptor with avoidant attachment. This suggests that the influence of maternal care on attachment security is not the same for all children. One theoretical basis for this is that it makes biological sense for children to vary in their susceptibility to rearing influence.
As a theory of socioemotional development, attachment theory has implications and practical applications in social policy, decisions about the care and welfare of children and mental health.
Child care policies
Social policies concerning the care of children were the driving force in Bowlby's development of attachment theory. The difficulty lies in applying attachment concepts to policy and practice. This is because the theory emphasises the importance of continuity and sensitivity in caregiving relationships rather than a behavioural approach on stimulation or reinforcement of child behaviours. In 2008 C.H. Zeanah and colleagues stated, "Supporting early child-parent relationships is an increasingly prominent goal of mental health practitioners, community based service providers and policy makers ... Attachment theory and research have generated important findings concerning early child development and spurred the creation of programs to support early child-parent relationships".
Historically, attachment theory had significant policy implications for hospitalised or institutionalised children, and those in poor quality daycare. Controversy remains over whether non-maternal care, particularly in group settings, has deleterious effects on social development. It is plain from research that poor quality care carries risks but that those who experience good quality alternative care cope well although it is difficult to provide good quality, individualised care in group settings.
Attachment theory has implications in residence and contact disputes, and applications by foster parents to adopt foster children. In the past, particularly in North America, the main theoretical framework was psychoanalysis. Increasingly attachment theory has replaced it, thus focusing on the quality and continuity of caregiver relationships rather than economic well-being or automatic precedence of any one party, such as the biological mother. Rutter noted that in the UK, since 1980, family courts have shifted considerably to recognize the complications of attachment relationships. Children tend to have attachment relationships with both parents and often grandparents or other relatives. Judgements need to take this into account along with the impact of step-families. Attachment theory has been crucial in highlighting the importance of social relationships in dynamic rather than fixed terms.
Attachment theory can also inform decisions made in social work, especially in humanistic social work (Petru Stefaroi), and court processes about foster care or other placements. Considering the child's attachment needs can help determine the level of risk posed by placement options. Within adoption, the shift from "closed" to "open" adoptions and the importance of the search for biological parents would be expected on the basis of attachment theory. Many researchers in the field were strongly influenced by it.
Clinical practice in children
Although attachment theory has become a major scientific theory of socioemotional development with one of the broadest, deepest research lines in modern psychology, it has, until recently, been less used in clinical practice than theories with far less empirical support.
This may be partly due to lack of attention paid to clinical application by Bowlby himself and partly due to broader meanings of the word 'attachment' used amongst practitioners. It may also be partly due to the mistaken association of attachment theory with the pseudoscientific interventions misleadingly known as "attachment therapy".
Prevention and treatment
In 1988, Bowlby published a series of lectures indicating how attachment theory and research could be used in understanding and treating child and family disorders. His focus for bringing about change was the parents' internal working models, parenting behaviours and the parents' relationship with the therapeutic intervenor. Ongoing research has led to a number of individual treatments and prevention and intervention programmes. They range from individual therapy to public health programmes to interventions designed for foster carers. For infants and younger children, the focus is on increasing the responsiveness and sensitivity of the caregiver, or if that is not possible, placing the child with a different caregiver. An assessment of the attachment status or caregiving responses of the caregiver is invariably included, as attachment is a two-way process involving attachment behaviour and caregiver response. Some programmes are aimed at foster carers because the attachment behaviours of infants or children with attachment difficulties often do not elicit appropriate caregiver responses. Modern prevention and intervention programmes have proven successful.
Reactive attachment disorder and attachment disorder
One atypical attachment pattern is considered to be an actual disorder, known as reactive attachment disorder or RAD, which is a recognized psychiatric diagnosis (ICD-10 F94.1/2 and DSM-IV-TR 313.89). Against common misconception, this is not the same as ‘disorganised attachment’. The essential feature of reactive attachment disorder is markedly disturbed and developmentally inappropriate social relatedness in most contexts that begins before age five years, associated with gross pathological care. There are two subtypes, one reflecting a disinhibited attachment pattern, the other an inhibited pattern. RAD is not a description of insecure attachment styles, however problematic those styles may be; instead, it denotes a lack of age-appropriate attachment behaviours that amounts to a clinical disorder. Although the term "reactive attachment disorder" is now popularly applied to perceived behavioural difficulties that fall outside the DSM or ICD criteria, particularly on the Web and in connection with the pseudo-scientific attachment therapy, "true" RAD is thought to be rare.
"Attachment disorder" is an ambiguous term, which may be used to refer to reactive attachment disorder or to the more problematical insecure attachment styles (although none of these are clinical disorders). It may also be used to refer to proposed new classification systems put forward by theorists in the field, and is used within attachment therapy as a form of unvalidated diagnosis. One of the proposed new classifications, "secure base distortion" has been found to be associated with caregiver traumatization.
Clinical practice in adults and families
As attachment theory offers a broad, far-reaching view of human functioning, it can enrich a therapist's understanding of patients and the therapeutic relationship rather than dictate a particular form of treatment. Some forms of psychoanalysis-based therapy for adults—within relational psychoanalysis and other approaches—also incorporate attachment theory and patterns. In the first decade of the 21st century, key concepts of attachment were incorporated into existing models of behavioural couple therapy, multidimensional family therapy and couple and family therapy. Specifically attachment-centred interventions have been developed, such as attachment-based family therapy and emotionally focused therapy.
Attachment theory and research laid the foundation for the development of the understanding of "mentalization" or reflective functioning and its presence, absence or distortion in psychopathology. The dynamics of an individual's attachment organization and their capacity for mentalization can play a crucial role in the capacity to be helped by treatment.
- Attachment parenting
- Attachment therapy
- Cinderella effect
- Complex post traumatic stress disorder
- Dyadic developmental psychotherapy
- Family therapy
- Gordon Neufeld
- Human bonding
- Nurture kinship
- Waters, E., Corcoran, D. & Anafarta, M. (2005) ‘Attachment, Other Relationships, and the Theory that All Good Things Go Together’ Human Development 48:80–84
- Landa, S., & Duschinsky, R. (2013) "Crittenden’s dynamic–maturational model of attachment and adaptation." Review of General Psychology 17.3
- Holmes p. 69.
- Howe, D. (2011) Attachment across the lifecourse, London: Palgrave
- Umemura, T., Jacobvitz, D., Messina, S. & Hazan, N. (2013) ‘Do toddlers prefer the primary caregiver or the parent with whom they feel more secure?’ Infant Behavior and Development 36(1): 102–114
- Bretherton I, Munholland KA (1999). "Internal Working Models in Attachment Relationships: A Construct Revisited". In Cassidy J, Shaver PR. Handbook of Attachment: Theory, Research and Clinical Applications. New York: Guilford Press. pp. 89–114. ISBN 1-57230-087-6.
- Prior & Glaser (2006) Understanding Attachment and Attachment Disorders, London: JKP, p.17
- Bowlby, J. (1960) ‘Separation Anxiety’ International Journal of Psychoanalysis, 41: 89-113
- Prior and Glaser p. 15.
- Bowlby (1969) 2nd ed. pp. 304–05.
- Kobak R, Madsen S (2008). "Disruption in Attachment Bonds". In Cassidy J, Shaver PR. Handbook of Attachment: Theory, Research and Clinical Applications. New York and London: Guilford Press. pp. 23–47. ISBN 978-1-59385-874-2.
- Prior and Glaser p. 16.
- Prior and Glaser p. 17.
- Prior and Glaser p. 19.
- Karen pp. 90–92.
- Ainsworth M (1967). Infancy in Uganda: Infant Care and the Growth of Love. Baltimore: Johns Hopkins University Press. ISBN 0-8018-0010-2.
- Karen p. 97.
- Prior and Glaser pp. 19–20.
- Bowlby (1969) p. 300.
- Bowlby (1969) 2nd ed. p. 309.
- Rutter, Michael (1995). "Clinical Implications of Attachment Concepts: Retrospect and Prospect". Journal of Child Psychology & Psychiatry 36 (4): 549–71. doi:10.1111/j.1469-7610.1995.tb02314.x. PMID 7650083.
- Main M (1999). "Epilogue: Attachment Theory: Eighteen Points with Suggestions for Future Studies". In Cassidy J, Shaver PR. Handbook of Attachment: Theory, Research and Clinical Applications. New York: Guilford Press. pp. 845–87. ISBN 1-57230-087-6. "although there is general agreement that an infant or adult will have only a few attachment figures at most, many attachment theorists and researchers believe that infants form 'attachment hierarchies' in which some figures are primary, others secondary, and so on. This position can be presented in a stronger form, in which a particular figure is believed continually to take top place ("monotropy") ... questions surrounding monotropy and attachment hierarchies remain unsettled"
- Mercer pp.39–40.
- Bowlby J (1973). Separation: Anger and Anxiety. Attachment and loss. Vol. 2. London: Hogarth. ISBN 0-7126-6621-4.
- Bowlby (1969) pp. 414–21.
- Bowlby (1969) pp. 394–395.
- Ainsworth MD (December 1969). "Object relations, dependency, and attachment: a theoretical review of the infant-mother relationship". Child Development (Blackwell Publishing) 40 (4): 969–1025. doi:10.2307/1127008. JSTOR 1127008. PMID 5360395.
- Ainsworth, M.D.S., Blehar, M. C., Waters, E., & Wall, S. (1978). Patterns of attachment: A psychological study of the strange situation. Hillsdale, NJ: Earlbaum.
- J. Cassidy & P. Shaver, (1999) Handbook of Attachment, NY:Guilford
- Snyder, R., Shapiro, S., & Treleaven, D. (2012). Attachment Theory and Mindfulness. Journal Of Child & Family Studies, 21(5), 709-717.
- Howe, D. (2011) Attachment across the lifecourse, London: Palgrave, p.13
- Schacter, D.L. et al. (2009). Psychology, Second Edition. New York: Worth Publishers. pp.441
- Aronoff, J. (2012). Parental Nurturance in the Standard Cross-Cultural Sample: Theory, Coding, and Scores. Cross-Cultural Research, 46(4), 315-347.
- Ainsworth MD, Blehar M, Waters E, Wall S (1978). Patterns of Attachment: A Psychological Study of the Strange Situation. Hillsdale NJ: Lawrence Erlbaum Associates. ISBN 0-89859-461-8.
- Solomon, J., George, C. & De Jong, A. (1995) Children classified as controlling at age six: Evidence of disorganized representational strategies and aggression at home and at school. Development and Psychopathology 7: 447-447
- Crittenden, P. (1999) ‘Danger and development: the organisation of self-protective strategies’ in Atypical Attachment in Infancy and Early Childhood Among Children at Developmental Risk ed. Joan I. Vondra & Douglas Barnett, Oxford: Blackwell pp. 145-171
- Ainsworth, M. D. & Bell, S. M. (1970), Attachment, exploration, and separation: Illustrated by the behavior of one-year-olds in a strange situation" Child Development 41:49-67
- Sroufe, A. & Waters, E. (1977) Attachment as an Organizational Construct" Child Development 48: 1184-1199
- Main, M. (1979) The "ultimate" causation of some infant attachment phenomena. Behavioral and Brain Sciences, 2: 640-643
- Main, M. (1977a) Analysis of a peculiar form of reunion behaviour seen in some day-care children. In R. Webb (ed.) Social Development in Childhood (pp.33-78), Baltimore: John Hopkins
- Ainsworth, M.D., Blehar, M, Waters, E, & Wall, S. (1978) Patterns of Attachment: A Psychological Study of the Strange Situation, Hillsdale, NJ: Lawrence Erlbaum, p.282
- Crittenden, P.M. (1983) ‘Mother and Infant Patterns of Attachment’ Unpublished PhD Dissertation, University of Virginia, May 1983, p.73
- Main, Mary; Solomon, Judith (1990). "Procedures for Identifying Infants as Disorganized/Disoriented during the Ainsworth Strange Situation". In Greenberg, Mark T.; Cicchetti, Dante; Cummings, E. Mark. Attachment in the Preschool Years: Theory, Research, and Intervention. Chicago: University of Chicago Press. pp. 121–60. ISBN 978-0-226-30630-8.
- Karlen Lyons-Ruth, Jean-Francois Bureau, M. Ann Easterbrooks, Ingrid Obsuth, Kate Hennighausen & Lauriane Vulliez-Coady (2013) Parsing the construct of maternal insensitivity: distinct longitudinal pathways associated with early maternal withdrawal, Attachment & Human Development, 15:5-6, 562-582
- Kochanska, Grazyna, and Sanghag Kim. "Early Attachment Organization With Both Parents and Future Behavior Problems: From Infancy to Middle Childhood." Child development 84.1 (2013): 283-296
- Svanberg, P.O. (2009). Promoting a secure attachment through early assessment and interventions. In J. Barlow & P.O. Svanberg (Eds.) Keeping the Baby in Mind, (pp. 100-114), London: Routledge.
- Ainsworth, M. (1990). ‘Epilogue’ in Attachment in the Preschool Years, ed. M.T. Greenberg, D. Ciccheti & E.M. Cummings. Chicago, IL: Chicago University Press, pp.463-488
- Solomon, J. & George, C. (1999a) The place of disorganisation in attachment theory. In Judith Solomon & Carol George (Eds) Attachment Disorganisation (pp3-32), p.27, NY: Guilford
- Sroufe, A. Egeland, B., Carlson, E. & Collins, W.A. (2005) The Development of the person: the Minnesota study of risk and adaptation from birth to adulthood, NY: Guilford Press, p.245
- Crittenden, P. (1999) ‘Danger and development: the organisation of self-protective strategies’ in Atypical Attachment in Infancy and Early Childhood Among Children at Developmental Risk ed. Joan I. Vondra & Douglas Barnett, Oxford: Blackwell pp. 159-160
- Crittenden, P. & Landini, A (2011) Assessing Adult Attachment: A Dynamic-Maturational Approach to Discourse Analysis, NY: W.W. Norton, p.269
- Main, Mary; Hesse, Erik (1993). "Parents' Unresolved Traumatic Experiences Are Related to Infant Disorganized Attachment Status: Is Frightened and/or Frightening Parental Behavior the Linking Mechanism?". In Greenberg, Mark T.; Cicchetti, Dante; Cummings, E. Mark. Attachment in the Preschool Years: Theory, Research, and Intervention. Chicago: University of Chicago Press. pp. 161–84. ISBN 978-0-226-30630-8.
- Colin Murray Parkes (2006). Love and Loss. Routledge, London and New York. p. 13. ISBN 0-415-39041-9.
- Madigan, Sheri, et al. "Unresolved states of mind, anomalous parental behavior, and disorganized attachment: A review and meta-analysis of a transmission gap." Attachment & human development 8.2 (2006): 89-111
- Solomon, J., & George, C. (2006). Intergenerational transmission of dysregulated maternal caregiving: Mothers describe their upbringing and child rearing. In O. Mayseless (Ed). Parenting representations: Theory, research, and clinical implications (pp. 265-295) Cambridge, UK: Cambridge University Press.
- Schaffer R (2007). Introducing Child Psychology. Oxford: Blackwell. pp. 83–121. ISBN 0-631-21628-6.
- Boris NW, Zeanah CH, Work Group on Quality Issues (2005). "Practice parameter for the assessment and treatment of children and adolescents with reactive attachment disorder of infancy and early childhood" (PDF). J Am Acad Child Adolesc Psychiatry 44 (11): 1206–19. doi:10.1097/01.chi.0000177056.41655.ce. PMID 16239871. Retrieved September 13, 2009.
- Main, M. & Cassidy, J. (1988) Categories of response to reunion with the parent at age 6. Developmental Psychology 24(3): 415-426
- Crittenden, P.M. (2008) Raising Parents: Attachment, Parenting and Child Safety, London: Routledge
- Bowlby, J. (1980) Loss, London: Penguin, p.45
- Strathearn, L., Fonagy, P., Amico, J.A., Montague, P.R. (2009). Adult attachment predicts mother's brain and peripheral oxytocin response to infant cues" Neuropsychopharmacology 34, 2655-2666
- Landa, S., & Duschinsky, R. (2013_ "Crittenden’s dynamic–maturational model of attachment and adaptation." Review of General Psychology 17.3
- p.435 in Crittenden, P. & Newman, L. (2010) Comparing models of borderline personality disorder: Mothers’ experience, self-protective strategies, and dispositional representations. Clinical Child Psychology and Psychiatry 15(3) 433–451
- Crittenden, P.M. (1992). Children’s strategies for coping with adverse home environments" Child Abuse & Neglect 16: 329-343
- Karlen Lyons-Ruth, Jean-Francois Bureau, M. Ann Easterbrooks, Ingrid Obsuth, Kate Hennighausen & Lauriane Vulliez-Coady (2013) Parsing the construct of maternal insensitivity: distinct longitudinal pathways associated with early maternal withdrawal, Attachment & Human Development, 15:5-6, 562-582,
- Pearce JW, Pezzot-Pearce TD (2007). Psychotherapy of abused and neglected children (2nd ed.). New York and London: Guilford press. pp. 17–20. ISBN 978-1-59385-213-9.
- Karen pp. 248–66.
- Berlin LJ, Cassidy J, Appleyard K (2008). "The Influence of Early Attachments on Other Relationships". In Cassidy J, Shaver PR. Handbook of Attachment: Theory, Research and Clinical Applications. New York and London: Guilford Press. pp. 333–47. ISBN 978-1-59385-874-2.
- Haltigan, JD; Ekas NV; Seifer R; Messinger DS (July 2011). "Attachment security in infants at-risk for autism spectrum disorders.". Attachment security in infants at-risk for autism spectrum disorders 41 (7): 962–967. doi:10.1007/s10803-010-1107-7. Retrieved 1 December 2011.
- Fraley RC, Spieker SJ (May 2003). "Are infant attachment patterns continuously or categorically distributed? A taxometric analysis of strange situation behavior". Developmental Psychology 39 (3): 387–404. doi:10.1037/0012-16220.127.116.117. PMID 12760508.
- Waters E, Beauchaine TP (May 2003). "Are there really patterns of attachment? Comment on Fraley and Spieker (2003)". Developmental Psychology 39 (3): 417–22; discussion 423–9. doi:10.1037/0012-1618.104.22.1687. PMID 12760512.
- Del Giudice M (2009). "Sex, attachment, and the development of reproductive strategies". Behavioral and Brain Sciences 32 (1): 1–67. doi:10.1017/S0140525X09000016. PMID 19210806.
- Waters E, Kondo-Ikemura K, Posada G, Richters J (1991). "Learning to love: Mechanisms and milestones". In Gunnar M, Sroufe T. Minnesota Symposia on Child Psychology 23 (Self–Processes and Development). Hillsdale, NJ: Erlbaum.
- Marvin RS, Britner PA (2008). "Normative Development: The Ontogeny of Attachment". In Cassidy J, Shaver PR. Handbook of Attachment: Theory, Research and Clinical Applications. New York and London: Guilford Press. pp. 269–94. ISBN 978-1-59385-874-2.
- Hazan C, Shaver PR (March 1987). "Romantic love conceptualized as an attachment process". Journal of Personality and Social Psychology 52 (3): 511–24. doi:10.1037/0022-3522.214.171.1241. PMID 3572722.
- Hazan C, Shaver PR (1990). "Love and work: An attachment theoretical perspective". Journal of Personality and Social Psychology 59 (2): 270–80. doi:10.1037/0022-35126.96.36.1990.
- Hazan C, Shaver PR (1994). "Attachment as an organisational framework for research on close relationships". Psychological Inquiry 5: 1–22. doi:10.1207/s15327965pli0501_1.
- Bartholomew K, Horowitz LM (August 1991). "Attachment styles among young adults: a test of a four-category model". Journal of Personality and Social Psychology 61 (2): 226–44. doi:10.1037/0022-35188.8.131.52. PMID 1920064.
- Fraley RC, Shaver PR (2000). "Adult romantic attachment: Theoretical developments, emerging controversies, and unanswered questions". Review of General Psychology 4 (2): 132–54. doi:10.1037/1089-26184.108.40.206.
- Pietromonaco PR, Barrett LF (2000). "The internal working models concept: What do we really know about the self in relation to others?". Review of General Psychology 4 (2): 155–75. doi:10.1037/1089-26220.127.116.11.
- Rholes WS, Simpson JA (2004). "Attachment theory: Basic concepts and contemporary questions". In Rholes WS, Simpson JA. Adult Attachment: Theory, Research, and Clinical Implications. New York: Guilford Press. pp. 3–14. ISBN 1-59385-047-6.
- Crowell JA, Fraley RC, Shaver PR (2008). "Measurement of Individual Differences in Adolescent and Adult Attachment". In Cassidy J, Shaver PR. Handbook of Attachment: Theory, Research and Clinical Applications. New York and London: Guilford Press. pp. 599–634. ISBN 978-1-59385-874-2.
- Bowlby J (1951). Maternal Care and Mental Health. Geneva: World Health Organisation. "Each put his finger on the child's inability to make relationships as being the central feature from which all other disturbances sprang, and on the history of institutionalisation or, as in the case quoted, of the child's being shifted about from one foster-mother to another as being its cause"
- Bowlby J (1944). "Forty-four juvenile thieves: Their characters and home life". International Journal of Psychoanalysis 25 (19–52): 107–27. "sometimes referred to by Bowlby's colleagues as "Ali Bowlby and the Forty Thieves""
- Spitz RA (1945). "Hospitalism: An Inquiry into the Genesis of Psychiatric Conditions in Early Childhood". The Psychoanalytic Study of the Child 1: 53–74. PMID 21004303.
- Spitz RA (1951). "The psychogenic diseases in infancy". The Psychoanalytic Study of the Child 6: 255–75.
- Schwartz J (1999). Cassandra's Daughter: A History of Psychoanalysis. New York: Viking/Allen Lane. p. 225. ISBN 0-670-88623-8.
- "Preface". Deprivation of Maternal Care: A Reassessment of its Effects. Public Health Papers (No. 14.). Geneva: World Health Organization. 1962.
- Bowlby (1988) p. 24.
- Rutter M (2008). "Implications of Attachment Theory and Research for Child Care Policies". In Cassidy J, Shaver PR. Handbook of Attachment: Theory, Research and Clinical Applications. New York and London: Guilford Press. pp. 958–74. ISBN 978-1-59385-874-2.
- Bowlby J (December 1986). "Citation Classic, Maternal Care and Mental Health" (PDF) 50 (18). Current Contents. Retrieved July 13, 2008.
- Lorenz KZ (1937). "The companion in the bird's world". The Auk 54: 245–73. doi:10.2307/4078077.
- Holmes p. 62.
- Van der Horst FCP, Van der Veer R, Van IJzendoorn MH (2007). "John Bowlby and ethology: An annotated interview with Robert Hinde". Attachment & Human Development 9 (4): 321–35. doi:10.1080/14616730601149809. PMID 17852051.
- Bowlby J (1953). "Critical Phases in the Development of Social Responses in Man and Other Animals". New Biology 14: 25–32.
- Bowlby (1969) 2nd ed. pp. 220–23.
- Crnic LS, Reite ML, Shucard DW (1982). "Animal models of human behavior: Their application to the study of attachment". In Emde RN, Harmon RJ. The development of attachment and affiliative systems. New York: Plenum. pp. 31–42. ISBN 978-0-306-40849-6.
- Brannigan CR, Humphries DA (1972). "Human non-verbal behaviour: A means of communication". In Blurton-Jones N. Ethological studies of child behaviour. Cambridge University Press. pp. 37–64. ISBN 978-0-521-09855-7. "... it must be emphasized that data derived from species other than man can be used only to suggest hypotheses that may be worth applying to man for testing by critical observations. In the absence of critical evidence derived from observing man such hypotheses are no more than intelligent guesses. There is a danger in human ethology ... that interesting, but untested, hypotheses may gain the status of accepted theory. [One author] has coined the term 'ethologism' as a label for the present vogue [in 1970] ... for uncritically invoking the findings from ethological studies of other species as necessary and sufficient explanations ... Theory based on superficial analogies between species has always impeded biological understanding ... We conclude that a valid ethology of man must be based primarily on data derived from man, and not on data obtained from fish, birds, or other primates"
- Schur M (1960). "Discussion of Dr. John Bowlby's paper". Psychoanalytic Study of the Child 15: 63–84. PMID 13749000. "Bowlby ... assumes the fully innate, unlearned character of most complex behavior patterns ... (whereas recent animal studies showed) ... both the early impact of learning and the great intricacy of the interaction between mother and litter" ... (and applies) ... "to human behavior an instinct concept which neglects the factor of development and learning far beyond even the position taken by Lorenz [the ethological theorist] in his early propositions"
- Schaffer HR, Emerson PE (1964). "The development of social attachment in infancy". Monographs of the Society for Research in Child Development, serial no. 94 29 (3).
- Anderson JW (1972). "Attachment behaviour out of doors". In Blurton-Jones N. Ethological studies of child behaviour. Cambridge: Cambridge University Press. pp. 199–216. ISBN 978-0-521-09855-7.
- Jones NB, Leach GM (1972). "Behaviour of children and their mothers at separation and greeting". In Blurton-Jones N. Ethological studies of child behaviour. Cambridge: Cambridge University Press. pp. 217–48. ISBN 978-0-521-09855-7.
- Hinde R (1982). Ethology. Oxford: Oxford University Press. p. 229. ISBN 978-0-00-686034-1.
- Freud A, Burlingham DT (1943). War and children. Medical War Books. ISBN 978-0-8371-6942-2.
- Holmes pp. 62–63.
- Holmes pp. 64–65.
- Steele H, Steele M (1998). "Attachment and psychoanalysis: Time for a reunion". Social Development 7 (1): 92–119. doi:10.1111/1467-9507.00053.
- Cassidy J (1998). "Commentary on Steele and Steele: Attachment and object relations theories and the concept of independent behavioral systems". Social Development 7 (1): 120–26. doi:10.1111/1467-9507.00054.
- Steele H, Steele M (1998). "Debate: Attachment and psychoanalysis: Time for a reunion". Social Development 7 (1): 92–119. doi:10.1111/1467-9507.00053.
- Johnson-Laird PN (1983). Mental models. Cambridge, MA: Harvard University Press. pp. 179–87. ISBN 0-674-56881-8.
- Main, M., Kaplan, N., & Cassidy, J. (1985). Security in Infancy, Childhood, and Adulthood: A Move to the Level of Representation. Monographs of the Society for Research in Child Development, 50, 66-104.
- Sroufe LA, Waters E (1977). "Attachment as an organizational construct". Child Development (Blackwell Publishing) 48 (4): 1184–99. doi:10.2307/1128475. JSTOR 1128475.
- Waters E, Cummings EM (2000). "A secure base from which to explore close relationships". Child Development 71 (1): 164–72. doi:10.1111/1467-8624.00130. PMID 10836570.
- Tronick EZ, Morelli GA, Ivey PK (1992). "The Efe forager infant and toddler's pattern of social relationships: Multiple and simultaneous". Developmental Psychology 28 (4): 568–77. doi:10.1037/0012-1618.104.22.1688.
- van IJzendoorn MH, Sagi-Schwartz A (2008). "Cross-Cultural Patterns of Attachment; Universal and Contextual Dimensions". In Cassidy J, Shaver PR. Handbook of Attachment: Theory, Research and Clinical Applications. New York and London: Guilford Press. pp. 880–905. ISBN 978-1-59385-874-2.
- Behrens KY, Hesse E, Main M (November 2007). "Mothers' attachment status as determined by the Adult Attachment Interview predicts their 6-year-olds' reunion responses: a study conducted in Japan". Developmental Psychology 43 (6): 1553–67. doi:10.1037/0012-1622.214.171.1243. PMID 18020832.
- Main M, Cassidy J (1988). "Categories of response to reunion with the parent at age 6: Predictable from infant attachment classifications and stable over a 1-month period". Developmental Psychology 24 (3): 415–26. doi:10.1037/0012-16126.96.36.1995.
- Harris JR (1998). The Nurture Assumption: Why Children Turn Out the Way They Do. New York: Free Press. pp. 1–4. ISBN 978-0-684-84409-1.
- Pinker S (2002). The Blank Slate: The Modern Denial of Human Nature. London: Allen Lane. pp. 372–99. ISBN 978-0-14-027605-3.
- Kagan J (1994). Three Seductive Ideas. Cambridge, MA: Harvard University Press. pp. 83–150. ISBN 978-0-674-89033-6.
- Vaughn BE, Bost KK, van IJzendoorn MH (2008). "Attachment and Temperament". In Cassidy J, Shaver PR. Handbook of Attachment: Theory, Research and Clinical Applications. New York and London: Guilford Press. pp. 192–216. ISBN 978-1-59385-874-2.
- Schaffer HR (2004). Introducing Child Psychology. Oxford: Blackwell. p. 113. ISBN 978-0-631-21627-8.
- Fonagy P, Gergely G, Jurist EL, Target M (2002). Affect regulation, mentalization, and the development of the self. New York: Other Press. ISBN 1-59051-161-1.
- Mercer pp. 165–68.
- Fonagy P, Gergely G, Target M. "Psychoanalytic Constructs and Attachment Theory and Research". In Cassidy J, Shaver PR. Handbook of Attachment: Theory, research and Clinical Applications. New York and London: Guilford Press. pp. 783–810. ISBN 978-1-59385-874-2.
- Belsky J, Rovine MJ (February 1988). "Nonmaternal care in the first year of life and the security of infant-parent attachment". Child Development (Blackwell Publishing) 59 (1): 157–67. doi:10.2307/1130397. JSTOR 1130397. PMID 3342709.
- Mercer pp. 160–63.
- Rutter M (Jan–February 2002). "Nature, nurture, and development: From evangelism through science toward policy and practice". Child Development 73 (1): 1–21. doi:10.1111/1467-8624.00388. PMID 14717240.
- Miyake K, Chen SJ (1985). "Infant temperament, mother's mode of interaction, and attachment in Japan: An interim report". In Bretherton I, Waters E. Growing Points of Attachment Theory and Research: Monographs of the Society for Research in Child Development. 50 (1–2, Serial No. 209. pp. 276–97. ISBN 978-0-226-07411-5.
- Mercer pp. 152–56.
- McHale JP (2007). "When infants grow up in multiperson relationship systems". Infant Mental Health Journal 28 (4): 370–92. doi:10.1002/imhj.20142.
- Zhang X, Chen C (2010). "Reciprocal Influences between Parents' Perceptions of Mother-Child and Father-Child Relationships: A Short-Term Longitudinal Study in Chinese Preschoolers". The Journal of Genetic Psychology 171 (1): 22–34. doi:10.1080/00221320903300387. PMID 20333893.
- Milanov, M., Rubin, M., & Paolini, S. (2013). Adult attachment styles as predictors of different types of ingroup identification. Bulgarian Journal of Psychology, 1-4, 175-186.
- Bugental DB (2000). "Acquisition of the Algorithms of Social Life: A Domain-Based Approach". Psychological Bulletin 126 (2): 178–219. doi:10.1037/0033-2909.126.2.187. PMID 10748640.
- Bugental DB, Ellerson PC, Rainey B, Lin EK, Kokotovic A (2002). "A Cognitive Approach to Child Abuse Prevention". Journal of Family Psychology 16 (3): 243–58. doi:10.1037/0893-3188.8.131.52. PMID 12238408.
- Ma, K. Attachment theory in adult psychiatry. Part 1: Conceptualisations, measurement and clinical research findings. Advances in Psychiatric Treatment. 2006 [Retrieved 2010-04-21];12:440–449.
- Fox NA, Hane AA (2008). "Studying the Biology of Human Attachment". In Cassidy J, Shaver PR. Handbook of Attachment: Theory, Research and Clinical Applications. New York and London: Guilford Press. pp. 811–29. ISBN 978-1-59385-874-2.
- Landers, MS; Sullivan, RM (2012). "The development and neurobiology of infant attachment and fear.". Developmental neuroscience 34 (2-3): 101–14. PMID 22571921. Retrieved Aug 17 2014.
- "Neurobiology of interpersonal connections". https://en.wikipedia.org/. Retrieved Aug 17 2014.
- Marshall PJ, Fox NA (2005). "Relationship between behavioral reactivity at 4 months and attachment classification at 14 months in a selected sample". Infant Behavior and Development 28 (4): 492–502. doi:10.1016/j.infbeh.2005.06.002.
- Prior and Glaser p. 219.
- Gillath O, Shaver PR, Baek JM, Chun DS (October 2008). "Genetic correlates of adult attachment style". Personality and Social Psychology Bulletin 34 (10): 1396–405. doi:10.1177/0146167208321484. PMID 18687882.
- Rutter M (2008). "Implications of Attachment Theory and Research for Child Care Policies". In Cassidy J, Shaver PR. Handbook of Attachment: Theory, Research and Clinical Applications. New York and London: Guilford Press. pp. 958–74. ISBN 978-1-60623-028-2.
- Rutter M, O'Connor TG (1999). "Implications of Attachment Theory for Child Care Policies". In Cassidy J, Shaver PR. Handbook of Attachment: Theory, Research and Clinical Applications. New York: Guilford Press. pp. 823–44. ISBN 1-57230-087-6.
- Berlin L, Zeanah CH, Lieberman AF (2008). "Prevention and Intervention Programs for Supporting Early Attachment Security". In Cassidy J, Shaver PR. Handbook of Attachment: Theory, Research and Clinical Applications. New York and London: Guilford Press. pp. 745–61. ISBN 978-1-60623-028-2.
- Karen pp. 252–58.
- Stefaroi, P. (2012). Humanistic Paradigm of Social Work or Brief Introduction in Humanistic Social Work. Social Work Review, (10)1, pp. 161–174. ICID 985513.
- Goldsmith DF, Oppenheim D, Wanlass J (2004). "Separation and Reunification: Using Attachment Theory and Research to Inform Decisions Affecting the Placements of Children in Foster Care". Juvenile and Family Court Journal. Spring: 1–14. Retrieved 2009-06-19.
- Crittenden, Patricia McKinsey, et al. "Assessing attachment for family court decision making." Journal of Forensic Practice 15.4 (2013): 237-248.
- Ziv Y (2005). "Attachment-Based Intervention programs: Implications for Attachment Theory and Research". In Berlin LJ, Ziv Y, Amaya-Jackson L, Greenberg MT. Enhancing Early Attachments: Theory, Research, Intervention and Policy. Duke series in child development and public policy. New York and London: Guilford Press. p. 63. ISBN 1-59385-470-6.
- Berlin LJ, Zeanah CH, Lieberman AF (2008). "Prevention and Intervention Programs for Supporting Early Attachment Security". In Cassidy J, Shaver PR. Handbook of Attachment: Theory, Research and Clinical Applications. New York and London: Guilford Press. pp. 745–61. ISBN 978-1-59385-874-2.
- Prior and Glaser pp. 231–32.
- Bakermans-Kranenburg M, van IJzendoorn M, Juffer F (2003). "Less is more: meta-analyses of sensitivity and attachment interventions in early childhood". Psychological Bulletin 129 (2): 195–215. doi:10.1037/0033-2909.129.2.195. PMID 12696839.
- Hoffman, Kent T., et al. "Changing toddlers' and preschoolers' attachment classifications: the Circle of Security intervention." Journal of Consulting and Clinical Psychology 74.6 (2006): 1017.
- Thompson RA (2000). "The legacy of early attachments". Child Development 71 (1): 145–52. doi:10.1111/1467-8624.00128. PMID 10836568.
- Chaffin M, Hanson R, Saunders BE, et al. (2006). "Report of the APSAC task force on attachment therapy, reactive attachment disorder, and attachment problems". Child Maltreatment 11 (1): 76–89. doi:10.1177/1077559505283699. PMID 16382093.
- Prior and Glaser pp. 223–25.
- Schechter DS, Willheim E (July 2009). "Disturbances of attachment and parental psychopathology in early childhood". Child and Adolescent Psychiatric Clinics of North America 18 (3): 665–86. doi:10.1016/j.chc.2009.03.001. PMC 2690512. PMID 19486844.
- Slade A (2008). "Attachment Theory and Research: Implications for the theory and practice of individual psychotherapy with adults". In Cassidy J, Shaver PR. Handbook of Attachment: Theory, Research and Clinical Applications. New York and London: Guilford Press. pp. 762–82. ISBN 978-1-59385-874-2.
- Sable P (2000). Attachment & Adult Psychotherapy. Northvale, NJ: Aaronson. ISBN 978-0-7657-0284-5.
- Johnson SM (2008). "Couple and Family Therapy: An Attachment Perspective". In Cassidy J, Shaver PR. Handbook of Attachment: Theory, Research and Clinical Applications. New York and London: Guilford Press. pp. 811–29. ISBN 978-1-59385-874-2.
- Johnson S (2002). Emotionally Focused Couples Therapy with Trauma Survivors. New York: Guilford Press. ISBN 978-1-59385-165-1.
- Allen JP, Fonagy P, ed. (2006). Handbook of Mentalization-Based Treatment. Chichester, UK: John Wiley & Sons. ISBN 978-0-470-01561-2.
- Ainsworth MD (1967). Infancy in Uganda. Baltimore: Johns Hopkins. ISBN 978-0-8018-0010-8.
- Bowlby J (1953). Child Care and the Growth of Love. London: Penguin Books. ISBN 978-0-14-020271-7.(version of WHO publication Maternal Care and Mental Health published for sale to the general public)
- Bowlby J (1969). Attachment. Attachment and Loss. Vol. I. London: Hogarth. (page numbers refer to Pelican edition 1971)
- Bowlby J (1999) . Attachment. Attachment and Loss Vol. I (2nd ed.). New York: Basic Books. ISBN 0-465-00543-8. OCLC 11442968. LCCN 00-266879; NLM 8412414.
- Bowlby J (1979). The Making and Breaking of Affectional Bonds. London: Tavistock Publications. ISBN 978-0-422-76860-3.
- Bowlby J (1988). A Secure Base: Clinical Applications of Attachment Theory. London: Routledge. ISBN 0-415-00640-6.
- Craik K (1943). The Nature of Explanation. Cambridge: Cambridge University Press. ISBN 978-0-521-09445-0.
- Holmes J (1993). John Bowlby & Attachment Theory. Makers of modern psychotherapy. London: Routledge. ISBN 0-415-07729-X.
- Karen R (1998). Becoming Attached: First Relationships and How They Shape Our Capacity to Love. Oxford and New York: Oxford University Press. ISBN 0-19-511501-5.
- Landa, S. & Duschinsky, R. "Crittenden’s dynamic–maturational model of attachment and adaptation." Review of General Psychology 17.3 (2013): 326-338.
- Mercer J (2006). Understanding Attachment: Parenting, child care, and emotional development. Westport, CT: Praeger Publishers. ISBN 0-275-98217-3. OCLC 61115448. LCCN 2005-19272.
- Prior V, Glaser D (2006). Understanding Attachment and Attachment Disorders: Theory, Evidence and Practice. Child and Adolescent Mental Health, RCPRTU. London and Philadelphia: Jessica Kingsley Publishers. ISBN 978-1-84310-245-8.
- Tinbergen N (1951). The study of instinct. Oxford: Oxford University Press. ISBN 978-0-19-857722-5.
- Powell, B., Cooper, G., Hoffman, K., Marvin, B. (2013). The Circle of Security Intervention: Enhancing Attachment in Early Parent-Child Relationships. New York: Guilford Press. ISBN 978-1-59385-314-3.
- Grossmann KE, Waters E (2005). Attachment from infancy to adulthood: The major longitudinal studies. New York: Guilford Press. ISBN 978-1-59385-381-5.
- Barrett H (2006). Attachment and the perils of parenting: A commentary and a critique. London: National Family and Parenting Institute. ISBN 978-1-903615-42-3.
- Crittenden PM (2008). Raising parents: attachment, parenting and child safety. Devon and Oregon: Willan Publishing. ISBN 978-1-84392-498-2.
- Bell DC (2010). The Dynamics of Connection: How Evolution and Biology Create Caregiving and Attachment. Lanham MD: Lexington. ISBN 978-0-7391-4352-0.
- Miller WB, Rodgers JL (2001). The Ontogeny of Human Bonding Sysytems: Evolutionary Origins, Neural Bases, and Psychological Manifestations. New York: Springer. ISBN 0-7923-7478-9.
- Goodall J (1971). In the Shadow of Man. Houghton Mifflin Co. ISBN 978-0-618-05676-7.
- Attachment & Human Development. London: Routledge. ISSN 1469-2988.
- Infant Mental Health Journal. Michigan Association for Infant Mental Health, WAIMH. ISSN 1097-0355.
- Van der Horst FCP (2011). John Bowlby - From Psychoanalysis to Ethology. Unraveling the Roots of Attachment Theory. Oxford: Wiley-Blackwell. ISBN 978-0-470-68364-4.
- Juffer F, Bakermans-Kranenburg MJ, Van IJzendoorn MH (2008). Promoting positive parenting: An attachment-based intervention. New York/London: Taylor and Francis Group. ISBN 978-0-8058-6352-9.
- Circle of Security International Website
- Attachment Theory and Research at Stony Brook
- The Attachment Theory Website
- Robert Karen: 'Becoming Attached'. The Atlantic Monthly February 1990.
- Review of Robert Karen. Becoming Attached: First Relationships and How They Shape Our Capacity to Love
- Rene Spitz's film "Psychogenic Disease in Infancy" (1957)
- The Parental Deficit Website
- "The origins of attachment theory:John Bowlby and Mary Ainsworth"