Agreeableness is a personality trait manifesting itself in individual behavioral characteristics that are perceived as kind, sympathetic, cooperative, warm and considerate. In contemporary personality psychology, agreeableness is one of the five major dimensions of personality structure, reflecting individual differences in cooperation and social harmony. People who score high on this dimension tend to believe that most people are honest, decent, and trustworthy.
People scoring low on agreeableness are generally less concerned with others' well-being and report having less empathy. Therefore, these individuals are less likely to go out of their way to help others. Low agreeableness is often characterized by skepticism about other people's motives, resulting in suspicion and unfriendliness. People very low on agreeableness have a tendency to be manipulative in their social relationships. They are also more likely to compete than to cooperate.
Agreeableness is considered to be a superordinate trait, meaning that it is a grouping of personality sub-traits that cluster together statistically. The lower-level traits, or facets, grouped under agreeableness are: trust, straightforwardness, altruism, compliance, modesty, and tender-mindedness.
Cattell's 16 Personality Factors 
Like all Big Five personality traits, the roots of the modern concept of agreeableness can be traced to a 1936 study by Gordon Allport and Henry S. Odbert. Seven years later, Raymond Cattell published a cluster analysis of the thousands of personality-related words identified by Allport and Odbert. The clusters identified in this study served as a foundation for Cattell's further attempts to identify fundamental, universal, human personality factors. He eventually settled on 16 personality factors through the use of factor analysis. Further factor analyses revealed five higher-order, or "global", factors to encompass these 16. Although labelled "independence" by Cattell, a global factor defined by high scores on the E, H, L, and Q1 factors of the 16PF Questionnaire was an early precursor to the modern concept of agreeableness.
The Big Five 
Extent of agreeableness in the five factor model of personality is most commonly assessed through self-report measures, although peer-reports and third-party observation can also be used. Self-report measures are either lexical or based on statements. Which measure of either type is used is determined by an assessment of psychometric properties and the time and space constraints of the research being undertaken.
Lexical measures use individual adjectives that reflect agreeableness or disagreeableness traits, such as sympathetic, cooperative, warm, considerate, harsh, unkind, rude. Words representing disagreeableness are reverse coded. Goldberg (1992) developed a 20-word measure as part of his 100-word Big Five markers, and Saucier (1994) developed a briefer 8-word measure as part of his 40-word mini-markers. Thompson (2008)  systematically revised and improved these markers to develop a 40-word measure with better psychometric properties in both American and non-American populations, the International English Mini-Markers. This brief measure has good internal consistency reliabilities and other validity for assessing agreeableness and other five factor personality dimensions, both within and, especially, without American populations. Internal consistency reliability of the Agreeableness measure for native English-speakers is reported as .86, that for non-native English-speakers is .80.
Statement measures tend to comprise more words, and hence consume more research instrument space, than lexical measures. Respondents are asked the extent to which they, for example, Am on good terms with nearly everyone, Am not interested in other people's problems or Sympathize with others' feelings.
Cattell's factor analytic approach, used to identify the universal personality structures, inspired countless studies in the decades following the introduction of the 16PF. Using Cattell's original clusters, the 16 Personality Factors, and original data, multiple researchers independently developed a five factor model of personality over this period. From the early 1960s on, these explorations typically included a factor called "agreeableness" or "sociability." Despite repeated replications of five stable personality factors following Cattell's pioneering work, this framework only began to dominate personality research in the early 1980s with the work of Lewis Goldberg. Using lexical studies similar to those of Allport and Odbert, Goldberg chose the term "Big Five" to reflect the sheer number of personality-related terms encompassed by each of these five distinct factors. One of these, agreeableness, was defined by a number of personality-related words similar to those present in earlier and more recent manifestations of the construct; examples include "friendly," "good-natured," "cooperative," "trustful," "nurturing," "sociable," and "considerate."
NEO PI 
Beginning in the 1970s, Paul Costa and Robert McCrae began researching the development of personality assessments based on factor models. Beginning with cluster analyses of Cattell's 16 Personality Factors, Costa and McCrae initially settled on a three-factor model of personality. These three factors were neuroticism (vs. emotional stability), extraversion (vs. introversion), and openness (vs. closedness) to experience, resulting in the acronym "NEO." Due to similarities between their three-factor NEO Personality Inventory and Goldberg's Big Five, Costa and McCrae began to develop scales to assess agreeableness and conscientiousness in the early 1980s. This work culminated in the 1985 publication of the first NEO PI Manual to be based on the full Five Factor Model. Although this marked the introduction of agreeableness to the NEO PI, Costa and McCrae worked for an additional seven years to identify and elaborate on the facets comprising this factor in the Revised NEO Personality Inventory.
NEO PI facets 
In the NEO PI, each of the five factors identified by Costa and McCrae are identified with six lower-level traits. Known as facets, the lower-level traits subsumed by agreeableness were first introduced with the 1992 publication of the revised version of the NEO PI. Based on the modern NEO PI-R, the six facets of agreeableness are: Trust, straightforwardness, Altruism, Compliance, Modesty, and Tender-Mindedness.
Trust is a defining feature of psychosocial development, personality theory, and folk psychological conceptions of personality. Individuals who score high on this facet generally believe others' intentions to be benevolent. Those scoring low on this facet tend to be cynical and view others as suspicious, dishonest, or dangerous.
Despite a long history in moral philosophy, straightforwardness is not as vital to personality theory as the other facets of agreeableness. Those scoring high on straightforwardness tend to interact with others in a direct and frank manner. Low scorers are less direct, tend to be high in self-monitoring, and are generally deceitful or manipulative. Although the two concepts are not identical, those who score low on this trustworthiness tend to be high in Machiavellianism. According to Michael C. Ashton and Kibeom Lee, straightforwardness is similar to the honesty aspect of honesty-humility in the HEXACO Model.
Similar to altruism in animals and ethical altruism, this facet is defined by measures of selflessness, self-sacrifice, generosity, and consideration, courtesy, and concern for others. Altruism is similar to Alfred Adler's concept of social interest, which is a tendency to direct one's actions toward the betterment of society. Individuals who score low on Altruism tend to be discourteous, selfish, or greedy, a pattern of behaviors known as "self-interest" in Adlerian psychology.
As a facet of agreeableness, compliance is defined as an individual's typical response to conflict. Those who score high on compliance tend to be meek and mild, and to prefer cooperation or deference as a means of resolving conflict. Low scorers tend to be aggressive, antagonistic, quarrelsome, and vindictive.
While trust, straightforwardness, altruism, and compliance all refer to interpersonal or social behaviors, modesty refers to an individual's self-concept. Those who score high on modesty tend to be humble and other-focused, while low scorers tend to be arrogant and self-aggrandizing. Low modesty is otherwise known as conceitedness or Narcissism and, in extreme cases, can manifest as Narcissistic personality disorder. Otherwise known as "humility" in the Revised NEO Personality Inventory, modesty resembles the humility aspect of Honesty-Humility in the HEXACO Model.
Tender-mindedness is defined as the extent to which an individual's judgments and attitudes are determined by emotion. Coined by William James, this term was also prominent in early versions of the 16PF. Tender-mindedness is primarily defined by sympathy and corresponds to the International Personality Item Pool's "sympathy" scale. In contrast, "tough minded" is a trait associated with Psychoticism on the Eysenck Personality Questionnaire.
Equivalents in psychobiological models 
Models based on psychobiological theories of personality have each incorporated a factor similar to agreeableness. In Cloninger's Temperament and Character Inventory the character trait known as cooperativeness is highly similar to and positively correlated with agreeableness. In Zuckerman's alternative five model of personality the trait known as Aggression-hostility is inversely related to agreeableness.
HEXACO Model 
To address the absence of measures of Dark triad traits (i.e., narcissism, Machiavellianism, and psychopathy), Michael Ashton and Kibeom Lee proposed the addition of a sixth factor to the Five Factor Model. Validated with psycholexical studies similar to those used in the development of the Five Factor Model, the HEXACO Model adds Honesty-Humility to five factors resembling those in the NEO PI. Although Honesty-Humility does not directly correspond to any Big Five trait, it is strongly correlated with the Straightforwardness and Modesty facets of Big Five Agreeableness. As both of these facets are only weakly correlated with Big Five Agreeableness, Ashton and Lee suggest dividing NEO PI Agreeableness into two factors similar to those in the HEXACO Model: Honesty-Humility (i.e., Straightforwardness and Modesty) and a redefined Agreeableness (Trust, Altruism, Compliance, and Tender-Mindedness). Reflecting this conception of Honesty-Humility and HEXACO Agreeableness as unique though similar concepts, Ashton and Lee propose that they represent different aspects of reciprocal altruism: fairness (Honesty-Humility) and tolerance (Agreeableness).
Despite suggesting this reconceptualization of Agreeableness for the NEO PI, Ashton and Lee do not believe HEXACO Agreeableness is accurately captured by Trust, Altruism, Compliance, and Tender-Mindedness. In addition to accounting for these four facets of Big Five Agreeableness, the HEXACO Model's construction of Agreeableness includes content categorized under Neuroticism in the NEO PI (i.e., temperamentalness and irritability). To reflect the negative emotional content at the low end of HEXACO Agreeableness, this factor is also referred to as "Agreeableness (versus Anger)." The inclusion of anger in the definition of HEXACO Agreeableness further helps to differentiate this factor from Honesty-Humility. In response to offensive or transgressive actions, individuals who score low on Honesty-Humility tend not to respond immediately. Instead, they defer their response by planning their revenge and waiting for the perfect opportunity to enact it. Although those who score low on HEXACO Agreeableness also employ this premeditated strategy, they also tend to respond immediately with anger.
HEXACO Agreeableness facets 
To help capture the numerous distinctions between the Big Five and HEXACO models, Ashton and Lee propose four new facet labels in their conceptualization of Agreeableness: Forgiveness, Gentleness, Flexibility, and Patience. In addition to these four Agreeableness-specific facets, Lee and Ashton have proposed an additional "interstitial" facet located in a space shared by Agreeableness, Honesty-Humility, and Emotionality: Altruism versus Antagonism.
- Forgiveness: A measure of an individual's response to deception or other transgressions. Individuals who score high on this facet tend to regain their trust and re-establish friendly relations by forgiving the offender, while those who score low tend to hold a grudge. Also known as "Forgivingness."
- Gentleness: A measure of how an individual typically evaluates others. Individuals who score high on this facet tend to avoid being overly judgmental, while those who score low are highly critical and judgmental.
- Flexibility: A measure of behaviors related to compromise and cooperation. Individuals who score high on this facet prefer cooperation and compromise as means of resolving disagreement, while those who score low tend to be stubborn, argumentative, and unwilling to accommodate others.
- Patience: A measure of one's response to anger and aggravation. Individuals who score high on this facet tend to be able to tolerate very high levels of anger and maintain their composure while expressing anger. Those who score low on Patience have difficulties remaining calm while expressing their anger and tend to have quick tempers, becoming very angry in response to comparatively little provocation.
- Altruism versus Antagonism: Although shared between three HEXACO factors, Altruism versus Antagonism is moderately correlated with Agreeableness. This interstitial facet assesses the extent to which an individual is sympathetic, soft-hearted, and helpful, with low-scoring individuals tending toward an antagonistic interpersonal style.
Interpersonal relations 
Agreeableness is an asset in situations that require getting along with others. Compared to disagreeable persons, Agreeable individuals display a tendency to perceive others in a more positive light. Research does not necessarily support the notion that agreeable individuals are more conforming or that they are more easily influenced by others in making choices.
Because agreeable children are more sensitive to the needs and perspectives of others, they are less likely to suffer from social rejection. Specifically, research indicates that children who are less disruptive, less aggressive, and more skilled at entering play groups are more likely to gain acceptance by their peers.
One study found that people high in agreeableness are more emotionally responsive in social situations. This effect was measured on both self-report questionnaires and physiological measures, and offers evidence that extraversion and neuroticism are not the only Big Five personality factors that influence emotion. The effect was especially pronounced among women.
Research also shows that people high in agreeableness are more likely to control negative emotions like anger in conflict situations. Those who are high in agreeableness are more likely to use constructive tactics when in conflict with others, whereas people low in agreeableness are more likely to use coercive tactics. They are also more willing to give ground to their adversary and may "lose" arguments with people who are less agreeable. From their perspective, they have not really lost an argument as much as maintained a congenial relationship with another person.
A monk who'd trained extensively in compassion meditation (and accordingly changed his brain to experience more positive emotion) named Matthieu Ricard engaged in a debate with a hot-tempered professor while both were connected to machines that monitored their physiological and mental states. At the beginning of the debate, the professor was very upset and angry while Matthieu Ricard was calm. As the debate continued, the professor became calmer and calmer while Matthieu Ricard stayed calm. At the end of the discussion the professor was having such a good time that he didn't want to stop!
A central feature of agreeableness is its positive association with altruism and helping behaviour. Across situations, people who are high in agreeableness are more likely to report an interest and involvement with helping others. Experiments have shown that most people are likely to help their own kin, and help when empathy has been aroused. Agreeable people are likely to help even when these conditions are not present. In other words, agreeable people appear to be "traited for helping" and do not need any other motivations.
While agreeable individuals are habitually likely to help others, disagreeable people may be more likely to cause harm. Researchers have found that low levels of agreeableness are associated with hostile thoughts and aggression in adolescents, as well as poor social adjustment. People low in agreeableness are also more likely to be prejudiced against stigmatized groups such as the overweight.
When mental illness is present, low agreeableness may be associated with narcissistic and anti-social tendencies. In theory, individuals who are extremely high in agreeableness are at risk for problems of dependency. Empirical studies show that many more problems are associated with low agreeableness.
Agreeableness from childhood to adulthood 
Agreeableness is of fundamental importance to psychological well-being, predicting mental health, positive affect, and good relations with others. In both childhood and adolescence agreeableness has been tied to externalizing issues. Along with this it has also been implicated in outcomes to conflict management skills, school adjustment, peer-social status and self-esteem. Some work has been done looking into whether agreeableness levels through childhood have effects on adjustment and agreeableness into adulthood. Among young adults, individuals that have been diagnosed with either externalizing as well as internalizing disorders present lower levels of agreeableness and communion, and higher levels of negative emotionality, than those young adults without such disorders. Agreeableness also is reported to mediate links between anger and depression in young adults. Among college students, agreeableness is often associated with self-reports of emotional experience and control along with psycho-physiological responses to affectively charged stimuli. Across adulthood, low agreeableness has been found to be a health risk. High agreeableness, especially trust and honesty, has been linked to longevity.
A study done by Caspi, Elder, and Bem (1987) found that explosive and ill-tempered children were found to have higher rates of divorce as adults when compared with their even-tempered peers. Further, ill-tempered men had lower educational attainment, occupational status, and work stability, and ill-tempered women married men with similar low achievement profiles A second and more recent study by Shiner (2000) found that composite variables describing middle-childhood agreeableness and friendly compliance predicted adolescent academic performance, behavioral conduct, and social competence 10 years later
Most recent is a study done by Larsen, Pulkkinen, and Adams (2002) in which they looked at many different levels of childhood behavior and emotion and the correlation into adulthood agreeableness. In their first analyses, structure coefficients showed that childhood compliance, aggression, and self-control discriminated high-agreeableness from low-agreeableness in adults better than did activity versus passivity, constructiveness, and anxiety. In their second analyses, structure coefficients indicated that adulthood socialization and impulsivity discriminated high-agreeableness from low-agreeableness in adults better than did inhibition of aggression and anxiety. In linking childhood behavioral profiles to adulthood personality profiles, high-compliant, high-self-control, and low-aggressive children were most likely to become high-agreeable, high-socialized, and low-impulsive adults. These children were more unlikely to become low-agreeable, low-socialized, and high-impulsive adults. Further, low-compliant, low-self-control, and high-aggressive children were likely to become low-agreeable, low-socialized, and high-impulsive adults and these children were unlikely to become high-agreeable, high-socialized, and low-impulsive adults. In addition to this, children classified as low-compliance, low-self-control, low-aggression types and children classified as high-compliance, high-self-control, low-aggression types had a greater probability of becoming adults with high-agreeableness, high-socialization, high-impulsivity profiles. Looking at stability of agreeableness they found results that indicated that stable low agreeable individuals reported less career stability and more depression when compared with stable high agreeable individuals and low to high agreeable individuals. Further, stable high agreeable individuals reported lower levels of alcoholism than did the other groups and fewer arrests than did stable low agreeable individuals.
In the United States, people in the West, Midwest, and South tend to have higher average scores on agreeableness than people living in other regions. According to researchers, the top ten most agreeable states are North Dakota, Minnesota, Mississippi, Utah, Wisconsin, Tennessee, North Carolina, Georgia, Oklahoma, and Nebraska. These findings are consistent with well known expressions in these states, such as "southern hospitality" and "Minnesota nice." Because these states are generally less urbanized than the east and west coasts, people may be more likely to live in small communities and know their neighbors. Consequently, they may be more willing to care about and help their neighbours.
In a study done by Albright et al. (1997) groups of college students from China and the United States rated strangers from both countries on the "Big Five" personality traits, external traits, and how well they were dressed. They found that both Chinese and U.S. students rated faces as showing similar levels of agreeableness and extroversion. The people who were thought to be the most agreeable wore smiles, a facial expression that is recognized around the world. The findings of the research seem to suggest that the trait of agreeableness is attributed to people in a universal way.
See also 
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Further reading 
Personality and career choices—Study published in the African Journal of Business Management