Emotional contagion is the phenomenon of having one person's emotions and related behaviors directly trigger similar emotions and behaviors in other people. Emotions can be shared across individuals in many different ways both implicitly or explicitly. For instance, conscious reasoning, analysis and imagination have all been found to contribute to the phenomenon. The behaviour has been found in humans, other primates, dogs, and chickens. 
Emotional contagion is important to personal relationships because it fosters emotional synchrony between individuals. A broader definition of the phenomenon suggested by Schoenewolf is "a process in which a person or group influences the emotions or behavior of another person or group through the conscious or unconscious induction of emotion states and behavioral attitudes". One view developed by Elaine Hatfield, et al., is that this can be done through automatic mimicry and synchronization of one's expressions, vocalizations, postures and movements with those of another person. When people unconsciously mirror their companions' expressions of emotion, they come to feel reflections of those companions' emotions.
The phrase "emotional contagion" embodies the idea that humans synchronize their own emotions with the emotions expressed by those around them, whether consciously or unconsciously. James Balwin had addressed the phenomena in his 1897 work Social and Ethical Interpretations in Mental Development, though using the term 'contagion of feeling'. Various 20th scholars had discussed the phenomena under the heading 'social contagion'. The actual term 'emotional contagion' appeared in Reber's 1985 The Penguine Dictionary of Psychology.  In a 1993 paper, Psychologists Elaine Hatfield, John Cacioppo, and Richard Rapson define it as "the tendency to automatically mimic and synchronize expressions, vocalizations, postures, and movements with those of another person's [sic] and, consequently, to converge emotionally" (p. 96).
Hatfield, et al., theorize emotional contagion as a two-step process: Firstly, we imitate people, e.g., if someone smiles at you, you smile back. Secondly, our own emotional experiences change based on the non-verbal signals of emotion that we give off. For example, smiling makes one feel happier and frowning making one feel worse. Mimicry seems to be one foundation of emotional movement between people.
Emotional contagion and empathy have an interesting relationship, in that they share similar characteristics, with the exception of the ability to differentiate between personal and pre-personal experiences, a process known as individuation.[clarification needed] In The Art of Loving (1956), social psychologist Erich Fromm explores these differences, suggesting that autonomy is necessary for empathy, which is not found in emotional contagion.
There are several factors that determine the rate and extent of emotional convergence in a group. Some of these are: membership stability, mood-regulation norms, task interdependence and social interdependence. Besides these event-structure properties, there are personal properties of the group's members, such as openness to receive and transmit feelings, demographic characteristics and dispositional affect that influence the intensity of emotional contagion.
Research regarding the concept of emotional contagion has been conducted from a variety of perspectives, including organizational, social, familial, developmental, and neurological contexts. While early research suggested that conscious reasoning, analysis, and imagination accounted for the idea of emotional contagion, it has been concluded that some forms of more primitive emotional contagion are far more subtle, automatic, and universal.
Hatfield, Cacioppo, and Rapson's 1993 research into emotional contagion reported that people's conscious assessments of others' feelings were heavily influenced by what others said. People's own emotions, however, were more influenced by others' nonverbal clues as to what they were really feeling. Recognizing emotions and acknowledging their origin can be one way to avoid emotional contagion. Transference of emotions has been studied in a variety of situations and settings, with social and physiological causes being two of the largest areas of research.
In addition to the social contexts discussed above, emotional contagion is a concept that has been studied within organizations. Schrock, Leaf, and Rohr (2008) discuss that organizations, like societies, have emotion cultures that consist of languages, rituals, and meaning systems, including rules about the feelings workers should, and should not, feel and display. They state that the concept of emotion culture is quite similar to the notion of "emotion climate" (p. 46), which has also been synonymously referred to as morale, organizational morale, and corporate morale. Furthermore, Worline, Wrzesniewski, and Rafaeli (2002) mention that organizations have an overall "emotional capability" (p. 318), while McColl-Kennedy and Smith (2006) examine the concept of "emotional contagion" (p. 255) specifically in customer interactions. These terms are arguably all attempting to describe a similar phenomenon; each term is different from one another in subtle and somewhat indistinguishable ways. Future research might consider where and how the meanings of these terms intersect, as well as how they differ.
A controversial experiment demonstrating emotional contagion using the social media platform Facebook was carried out in 2012 on 689,000 users by filtering positive or negative emotional content from their news feeds. The experiment sparked uproar among people who felt the study violated personal privacy. The 2014 publication of a research paper resulting from this experiment, "Experimental evidence of massive-scale emotional contagion through social networks", a collaboration between Facebook and Cornell University, is described by Tony D. Sampson, Stephen Maddison, and Darren Ellis (2018) as a "disquieting disclosure that corporate social media and Cornell academics were so readily engaged with unethical experiments of this kind." Tony D. Sampson et al. criticize the notion that “academic researchers can be insulated from ethical guidelines on the protection for human research subjects because they are working with a social media business that has ‘no obligation to conform’ to the principle of ‘obtaining informed consent and allowing participants to opt out’.” A subsequent study confirmed the presence of emotional contagion on Twitter without manipulating users' timelines.
Beyond the ethical concerns, some scholars criticized the methods and reporting of the Facebook findings. John Grohol, writing for Psych Central, argued that despite its title and claims of "emotional contagion," this study did not look at emotions at all. Instead, its authors used an application (called "Linguistic Inquiry and Word Count" or LIWC 2007) that simply counted positive and negative words in order to infer users' sentiments. He wrote that a shortcoming of the LIWC tool is that it does not understand negations. Hence, the tweet "I am not happy" would be scored as positive: "Since the LIWC 2007 ignores these subtle realities of informal human communication, so do the researchers." Grohol concluded that given these subtleties, the effect size of the findings are little more than a "statistical blip."
Kramer et al. (2014) found a 0.07%—that's not 7 percent, that's 1/15th of one percent!!—decrease in negative words in people's status updates when the number of negative posts on their Facebook news feed decreased. Do you know how many words you'd have to read or write before you've written one less negative word due to this effect? Probably thousands.
Emotions can be shared and mimicked in many different ways. Early investigators of emotional contagion believed that "conscious reasoning, analysis and imagination accounted for this phenomenon." However, it is known now that some forms of emotional contagion are more subtle and automatic than early theorists suggested.
Unlike cognitive contagion, emotional contagion is less conscious and more automatic. It relies mainly on non-verbal communication, although it has been demonstrated that emotional contagion can, and does, occur via telecommunication. For example, people interacting through e-mails and "chats" are affected by the other's emotions, without being able to perceive the non-verbal cues.
One view, proposed by Hatfield and colleagues, describes the emotional contagion process as a primitive, automatic and unconscious behavior. According to this research group, it takes place through a series of steps. When a receiver is interacting with a sender, he perceives the emotional expressions of the sender. The receiver automatically mimics those emotional expressions. Through the process of afferent feedback, these new expressions are translated into feeling the emotions the sender feels, thus leading to emotional convergence.
Another view, emanating from social comparison theories, sees emotional contagion as demanding more cognitive effort and being more conscious. According to this view, people engage in social comparison to see if their emotional reaction is congruent with the persons around them. In this case, the recipient uses the emotion as a type of social information to understand how he or she should be feeling. People respond differentially to positive and negative stimuli, and negative events tend to elicit stronger and quicker emotional, behavioral, and cognitive responses than neutral or positive events. Thus, unpleasant emotions are more likely to lead to mood contagion than are pleasant emotions. Another variable that needs to be taken into account is the energy level at which the emotion is displayed. As higher energy draws more attention to it, the prediction is that the same emotional valence (pleasant or unpleasant) expressed with high energy will lead to more contagion than if expressed with low energy.
Contrary to the automatic infection of feelings described above, there are times when others' emotions are being manipulated by a person or a group in order to achieve something. This can be a result of intentional affective influence by a leader or team member. Suppose this person wants to convince the others of something, he may do so by sweeping them up in his enthusiasm. In such a case, his positive emotions are an act with the purpose of "contaminating" the others' feelings. A different kind of intentional mood contagion is by giving the group a reward, or treat, in order to alleviate their feelings.
In the organizational psychology literature, a growing body of research is dedicated to the aspects of emotional labor. In short, it deals with the need to manage emotions so that they are consistent with organizational or occupational display rules, regardless of whether they are discrepant with internal feelings. In regard to emotional contagion, in work settings that require a certain display of emotions, one finds himself obligated to display, and consequently feel, these emotions. In a process where surface acting develops into deep acting, emotional contagion is the byproduct of intentional affective impression management.
In workplaces and organizations
Many organizations and workplaces are currently encouraging team-work. This is a move driven by studies conducted by organizational psychologists that highlight the benefits of work-teams. Emotions come into play and a group emotion is formed.
The group's emotional state has an influence on factors such as cohesiveness, morale, rapport and the team's performance. For this reason, organizations need to take into account the factors that shape the emotional state of the work-teams, in order to harness the beneficial sides and avoid the detrimental sides of the group's emotion. Managers and team leaders should be even more cautious with their behavior, since their emotional influence is greater than that of a "regular" team member. It has been shown that leaders are more emotionally "contagious" than others.
The interaction between service employees and customers is considered an essential part of both customers' assessments of service quality and their relationship with the service provider. Positive affective displays in service interactions are positively associated with important customer outcomes, such as intention to return and to recommend the store to a friend. It is the interest of organizations that their customers be happy, since a happy customer is a satisfied one. Research has shown that the emotional state of the customer is directly influenced by the emotions displayed by the employee/service provider via emotional contagion. But, this influence is dependent on the degree of authenticity of the employee's emotional display, such that if the employee is only surface-acting, the contagion of the customer is poor, in which case the beneficial effects stated above will not occur.
Vittorio Gallese posits that mirror neurons are responsible for intentional attunement in relation to others. Gallese and colleagues at the University of Parma found a class of neurons in the premotor cortex that discharge when macaque monkeys execute goal-related hand movements or when they watch others doing the same action. One class of these neurons fires with action execution and observation, and with sound production of the same action. Research in humans shows an activation of the premotor cortex and parietal area of the brain for action perception and execution.
Gallese continues his dialogue to say humans understand emotions through a simulated shared body state. The observers' neural activation enables a direct experiential understanding. "Unmediated resonance" is a similar theory by Goldman and Sripada (2004). Empathy can be a product of the functional mechanism in our brain that creates embodied simulation. The other we see or hear becomes the "other self" in our minds. Other researchers have shown that observing someone else's emotions recruits brain regions involved in (a) experiencing similar emotions and (b) producing similar facial expressions. This combination of activations indicates that the observer activates (a) a representation of the emotional feeling of the other individual which would lead to emotional contagion and (b) a motor representation of the observed facial expression that could lead to facial mimicry. In the brain, understanding and sharing other individuals' emotions would thus be a combination of emotional contagion and facial mimicry. Importantly, more empathic individuals experience more brain activation in emotional regions while witnessing the emotions of other individuals.
The amygdala is one part of the brain mechanism that underlies empathy and allows for emotional attunement and creates the pathway for emotional contagion. The basal areas including the brain stem form a tight loop of biological connectedness, re-creating in one person the physiological state of the other. Psychologist Howard Friedman thinks this is why some people can move and inspire others. The use of facial expressions, voices, gestures and body movements transmit emotions to an audience from a speaker.
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