Michael D. Buhrmester & William B. Swann Jr.
“Identity Fusion”
Essay by Michael D. Buhrmester and William B. Swann Jr., "Identity Fusion," appears below.
To read the original essay, including footnotes, click here.
William B. Swann, Jr. is a professor of Social, Personality and Clinical Psychology at the University of Texas at Austin. He has received research grants and research scientist development awards from the National Institute of Mental Health, the National Science Foundation, the National Institute of Drug and Alcohol Abuse and the Carnegie Foundation. His web site is here.

Michael D. Buhrmester is a post-doctoral researcher at the University of Oxford in Oxford, UK & currently visiting research fellow at Queen’s University in Belfast, Northern Ireland. Find him on the web here.


Why do some soldiers instinctively risk life and limb for their compatriots? Why do some community members sacrifice their own financial security by donating their time and treasure to needy others? And why do some employees selflessly endure personal hardship for their organization? We propose that a new approach to understanding the interplay of the personal self and group identity—identity fusion—provides a promising new perspective on each of these phenomena.

The identity fusion approach assumes that group members sometimes develop a powerful, visceral sense of “oneness” with their group. Dozens of studies now demonstrate that identity fused persons are more apt to endorse extreme pro-group behavior, especially endorsement of extreme acts such as sacrificing one’s own life.

By specifying some of the key antecedents of extreme pro-group behavior, the identity fusion approach fills an important explanatory gap left largely unaddressed by past perspectives on group processes. To accomplish this aim, the identity fusion framework focuses on several aspects of group processes that have been de-emphasized or overlooked by the past formulations described below.


The identity fusion perspective shares some features with group phenomena studied by other behavioral scientists. As does the self-expansion model of interpersonal closeness, and Whitehouse’s “imagistic” mode of religiosity, fusion theory assumes that interpersonal relationships and the meaningful memories created within them play a key role in solidifying the bond between members and the group. Akin to Turner’s notion of “spontaneous communitas” and Durkheim’s notions of solidarity, the fusion approach posits that individuals vary in the extent to which they see other group members as homogeneous versus uniquely valuable.

Of all the formulations that are related to identity fusion, however, the closest is the social identity approach, which embraces two theories, social identity and self-categorization). Similar to the identity fusion approach, the social identity approach rests on a distinction between people’s personal identities (i.e., aspects of self that make people unique) and social identities (i.e., aspects of self that align them with groups, such as being an American or Catholic).

The social identity approach, however, assumes that personal and social identities are hydraulically related, with increases in the salience of one producing decreases in the salience of the other.  This assumption implies that when   it comes to motivating group-related behavior, social identities and degree of alignment with the group category are all that matter; qualities of individual group members, including their personal identities and idiosyncratic relationships with others group members, do not.

Moreover, social identity theory suggests that group members are bound to other group members only insofar as such group members embody the prototypic qualities of   the group. From this vantage point, the unique relationships that group members establish with one another are not thought to foster identification with the group. In contrast, fusion presumably involves a deep connection between the person and the entire group, which includes not simply the group category but also its individual members.

The more active role accorded to the personal self in fusion as compared to identification is reflected in the way the two constructs are measured. Self-report scales designed to measure identification often place respondents in a reactive role, with items that focus on how group membership impacts the individual (e.g., If a story in the media criticized my group, I would feel embarrassed).

In contrast, measures of identity fusion emphasize the mutual interplay of the personal self and group, including items denoting a strong connection with the group (e.g., I am one with my group), but also items indicating feelings of personal agency in the service of the group (I make my group strong). Over three dozen studies have shown that measures of identity fusion predict pro-group behavior more effectively than measures of identification, especially when the behavior involves extreme sacrifices, such as giving up one’s life for the group.

But identity fusion does not merely predict extreme pro-group behavior better than measures of identification; it also interacts with contextual variables in unique ways. We offer four examples. First, to test the notion that fused individuals are motivated to engage in pro-group behavior by their personal as well as social self-views, researchers experimentally increased feelings of personal agency by increasing physiological arousal through physical exercise.

Consistent with predictions, they discovered that increases in arousal bolstered the extent to which fused individuals endorsed extreme pro-group behavior, including sacrificing one’s life for the group. This pattern did not emerge among highly identified persons.

Second, the fusion approach assumes that as a result of the powerful feelings of oneness that fused persons have with their group, the situational influences that activate their personal or group identity will simultaneously activate the other. For instance, activating the personal selves of fused persons by asking them how they would react to threat to their personal well-being increased their subsequent endorsement of sacrifices for the group. This pattern did not emerge among highly identified persons.

Third, as noted above, the fusion approach assumes that strongly fused per- sons care not only about their collective ties to the “group” as an abstract entity, but they also care deeply about their real or imagined relationships with individuals in the group. Consistent with this reasoning, highly fused persons were especially likely to endorse sacrificing their own lives to save the lives of individual members of the group who they perceived to be imperiled. No such pattern emerged among highly identified persons.

Fourth, the fusion approach assumes that once a person develops a high level of fusion, his or her level of fusion will tend to remain highly stable over time despite variation in context. To test this idea, researchers had participants complete the fusion scale and then, 1–18 months later, they had them complete it again.

Participants who initially scored high on the fusion scale (i.e., in the upper tertile) tended to remain high over time compared to those who initially scored lower. This notion of “irrevocability” amongst strongly fused persons stands in contrast to the past emphasis on the situational specificity of identification.


An expanding empirical record supports fusion’s role as an antecedent to various pro-group behaviors. Below we offer a selective review of past and ongoing work.


Since the experimental study of actual extreme pro-group acts raises large ethical red flags, with a few exceptions researchers have focused on endorsements of extreme pro-group acts. For example, Swann et al. developed a 7-item self-report measure of intentions to fight and die on behalf of one’s group (e.g., “I would fight someone threatening another group member,” “I would sacrifice my life if it saved another group member’s life”).

Across studies involving participants in dozens of countries from six continents, fusion robustly predicted responses to the fight and die measure while controlling for identification.

Other researchers have developed original moral dilemmas based on the classic “trolley dilemma”. These dilemmas pit self-preservation against self-sacrifice for others.

In a prototypical dilemma, participants imagine that they are standing on a bridge overlooking a set of train tracks below. Five group members (e.g., ingroup or outgroup) are on the tracks imperiled by a rapidly approaching train, leaving the participant with a choice: (i) stand idly by as others are killed or (ii) jump to one’s death, causing the train to stop before crushing the hapless group members on the track.

Responses to several variations of this dilemma point to the same conclusion: strongly fused persons are especially willing to endorse sacrificing their lives for fellow ingroup members, but their altruism does not extend to outgroups. One follow-up study revealed that strongly fused members’ allegiances allow that some people fall in the grey area between ingroup and outgroup member, however.

That is, strongly fused Spaniards endorsed dying for non-Spaniard Europeans, an “extended” ingroup, but not a single participant endorsed saving Americans, an unequivocal “outgroup.” Apparently, strongly fused persons’ feelings of responsibility are strong but nuanced.

Taking a very different approach, researchers explored political party members’ divergent reactions to the outcomes of the 2008 national elections in Spain and the United States. Whereas strongly fused members predicted that their personal fortunes would rise or fall with the fate of their political parties, highly identified persons predicted that their fortunes would improve when the party won but remain the same when their party lost. These findings confirm past indications that political losers who are merely identified tend to detach themselves from the group following a group failure, but also show that strongly fused persons are poised to “go down with the ship.”


Although fusion was originally intended to explain extreme pro-group acts, it has also been used to explain less extreme but nevertheless personally costly and/or pro-group actions. In some cases, the costs are financial. For instance, in one study, strongly fused Spaniards were especially likely to donate personal funds to support financially distressed Spaniards. In response to the terrorist attack at the 2013 Boston Marathon, strongly fused Americans were more likely to donate personal funds to victims than were weakly fused Americans.

In other studies, strongly fused persons have provided social or emotional support to fellow group members. For instance, in one cross-cultural investigation, Canadian, Chinese, and Indian participants played a resource-allocation computer game designed to measure helping behaviors between players.

Players who were strongly fused with their home nation allocated more resources to fellow nation members in the game and made fewer selfish requests for aid than did weakly fused players. Similarly, following the Boston Marathon attack, strongly fused Americans were more likely to enact several actions that were emotionally supportive of the victims, such as writing heartfelt notes of support to victims.

Other recent evidence suggests that fusion motivates acts of sacrifice for individuals who technically are not yet group members. In a study       of transsexuals considering sex reassignment surgery, fusion with one’s psychological sex predicted whether individuals forged ahead with surgical procedures designed to irrevocably change their primary sex characteristics.

Individuals strongly fused with their psychological underwent surgery despite the known risks to their close friendships and family ties in addition to the physical health risks and pain associated with the surgeries. Apparently, for some, the desire to align one’s personal sense of self with a group is so strong that they are willing to endure considerable social and physical pain.

Recent research has also suggested that strongly fused persons endure personal costs to ensure that group-related injustices are righted. For instance, strongly fused employees were more likely than weakly fused employees to report having “blown the whistle” sometime during the course of their employment. Often, whistleblowers report being motivated by a sense that their actions will ultimately benefit the group.

To illuminate the antecedents of whistleblowing, researchers carefully choreographed an experiment in which students witnessed a fellow student (confederate) cheat on an exam. Students who were strongly fused with their university became incensed when they witnessed a fellow student cheating in ways that were costly to other students, and their emotional reactions motivated them to “blow the whistle” against the cheater despite a high perceived risk of retaliation.


To date, researchers have identified four key variables that underlie links between fusion and various pro-group actions. First, in line with the assumption that strongly fused individuals imbue pro-group action with a sense of personal agency, multiple studies have shown that physiological arousal and self-reported feelings of group-directed agency (e.g., I am responsible for my group’s actions) mediate links between fusion and pro-group behavior.

These results suggest that a wide range of physical activities common to groups throughout human history (e.g., ritual chanting, dancing, marching) may serve to prime the pro-group pump amongst fused persons.

Second, since fusion theory suggests that strongly fused persons believe that they strengthen the group just as the group strengthens them, researchers tested whether feelings of invulnerability underlie strongly fused persons’ endorsements of self-sacrifice. As expected, strongly fused persons endorsed items such as “My group will be able to cope with any sort of threat.”

Moreover, such feelings of invulnerability mediated their endorsement of self-sacrificial acts for other group members. Strongly fused persons’ feelings of group invulnerability may serve to insulate them from recognizing fully the risks associated with extreme pro-group behavior.

Third, in line with the highly emotional character of identity fusion, recent evidence suggests that strongly fused persons’ experience heightened negative emotions after receiving information indicating that their group is imperiled in some way.

For example, when strongly fused participants learned that group members might be killed in a hypothetical trolley dilemma, they became upset and these emotional reactions predicted subsequent endorsement of self-sacrifice for the group. Apparently, among strongly fused persons, learning that the group category or individual group members are endangered in some way triggers emotional reactions and these reactions motivate more endorsement of pro-group behavior.

Finally, consistent with the presumed centrality of real or imagined ties to other group members, recent evidence suggests that self-reported feelings of familial connection to all other group members statistically mediates link- ages between fusion and pro-group outcomes. In small groups where it is possible to know all the other members, projecting a family-like sense of knowing to other group members (e.g., as “brothers and sisters” or “sons and daughters”) may seem unsurprising. However, how do people manage to project familial ties in much larger groups, such as to one’s country? We consider these issues next.


There is still much to be learned about identity fusion. We turn first to the causal antecedents of fusion.


What experiences foster fusion? Whitehouse’s anthropological insights into ritual behaviors provide a compelling starting point here. Whitehouse has reported that some religious groups have developed infrequently used but highly arousing rituals (e.g., traumatic rites of passage) that serve to tighten within-group bonds. These rituals generate intensely dysphoric feelings that participants subsequently strive to understand by reflecting on them.

Such reflections eventually build a rich cognitive network that supports and amplifies participants’ positive feelings about the group. The ultimate result is fusion with the group. Expanding Whitehouse’s analysis of religious groups to other contexts (e.g., militias), a field study during the recent revolution in Libya supports this analysis.

Relative to a group of militia-men who provided logistical support, those engaged in combat reported feeling more fused to their militia than to their own families (i.e., true brothers in arms). In stark contrast, almost no militia members reported feeling fused with non-militia pro-revolutionaries, presumably because they did not share in the same battlefield trials and tribulations. Such findings shed light on why in the wake of victory in war smooth coordination within ingroup factions can be so difficult.

These insights into the development of fusion in small fighting units raise the related question of the development of fusion to much larger groups such as one’s nation. We suggest that the key is a tendency for group members to perceive that the members of the large group share some essential qualities that form the basis of a deep bond.

To test this notion, researchers primed perceptions of two common, essential components of close, kinship relationships: shared genetic heritage and shared core values. Results showed that these priming manipulations encouraged participants to perceive that they shared relational ties with the group (e.g., Members of my country are like my family to me). These relational ties, in turn, fostered willingness to self-sacrifice for other group members.


With respect to temporal stability, fusion resembles other identity related constructs such as self-esteem. Similar to self-esteem, fusion is internally reliable, temporally stable, and resistant to state manipulations. However, also as self-esteem, fusion might manifest itself in a state form that waxes and wanes temporarily around an average level. It thus seems plausible that contextual forces could influence people’s in-the-moment sense of fusion with a group.

To explore this possibility, researchers will first need to develop a valid measure of state fusion, perhaps by simply adapting instructions to focus on people’s most immediate thoughts and feelings. Second, researchers should seek to identify what sorts of experiences uniquely cause temporarily changes in state fusion that cannot be explained by changes in related constructs (e.g., social identification).

Using bottom-up approaches (e.g., daily diary studies), researchers could explore what day-to-day experiences, if any, tend to increase or decrease state fusion. Then researchers could unpack promising causal agents in more controlled lab settings.

Whitehouse’s work on ritual (2004) may provide some leads here. His work suggests that events that are highly arousing, relatively rare in frequency, and foster rich episodic memories stand a better chance at increasing fusion than events that lack these elements. Special, infrequent group events such as competitive events between groups (e.g., national sporting events), celebrations of group history (e.g., Chanukah) and days of remembrance for certain important group figures or certain subgroups (e.g., Memorial Day in the United States) may also amplify state fusion temporarily.

In addition to group events that are planned and ritual in nature, unexpected, impactful events may also temporarily buttress the collective and relational ties that bind individuals to the group. These events could take many possible forms: natural disasters (e.g., Hurricane Katrina in the United States), fortuitous discoveries (e.g., valued heirlooms or archaeological finds long thought lost), terrorist attacks, or so on.


Fusion theory was developed, in part, to explain extreme pro-group behaviors such as fighting and dying for one’s group. Past research on identity fusion has accordingly focused on outcome measures that are directly relevant to national military, paramilitary, or radical nongovernmental groups acting in defense of one’s nation. Increasingly however, researchers have expanded the range of outcomes related personally costly pro-group acts that are not self-sacrificial. In turn, more attention has been directed to other types of groups (e.g., political parties, work and academic organizations).

Researchers have distinguished two distinct forms of fusion. In local fusion, group members know one another directly (e.g., teammates, military fight- ing units). In extended fusion, any single group member may directly know only a tiny fraction of other members (e.g., a religious group, a collection of nations such as the European Union).

Given the broad definition of an extended group, the fusion lens could be theoretically focused on numerous groups, such as companies (e.g., Apple, Microsoft), belief-based groups (e.g., veganism), and groups based on demographic qualities (e.g., gender, age). Whatever the group may be, investigators should begin by asking themselves (i) do the qualities of the group and members generally align with the theoretical principles of the fusion construct, and (ii) is there sufficient variation in members’ experiences and bonds with the group to justify an individual differences perspective? If answers to both of these two questions are in the affirmative, the fusion approach may prove illuminating.


Recent scholars of moral psychology have provided a compelling answer as to why people so often disagree about morally-charged issues: At a fundamental, oft-unrecognized level, situations trigger moral principles that vary from person-to-person.

But what about situations in which all people know what is moral, but only some decide to actually do it? We explored this very question by gathering people’s in-the-moment thoughts and feelings as they contemplated sacrificing their life to save the lives of fellow group members.

The results revealed that when strongly fused persons believed that self-sacrifice was moral, they endorsed it; in contrast, when weakly fused persons believed that self-sacrifice was moral, they often eschewed it in favor of actions that would save their own life.

It therefore appears that the story of moral action begins but does not always end with one’s moral conviction. Instead, the alignments people form with other group members can sometimes be a more powerful motivator of moral behavior than moral conviction.


Since Le Bon first explored the phenomena of crowd psychology, many have contended that the process of immersing oneself in a group is marked by a process he dubbed “submergence.” In this process, the individuals in the crowd lose their sense of individual self and personal responsibility to the group.

As such, the person becomes a mere carrier of the sentiments of the collective, a carrier stripped of personal agency. Lately, variations of this approach have resurfaced in contemporary accounts that feature uncertainty-reduction or existential anxiety-reduction as the motive for group bonding.

In contrast to these accounts, the identity fusion approach features mechanisms that are very much the opposite of uncertainty and anxiety reduction. As numerous investigations now show, strongly fused persons are emboldened by feelings of personal agency, invulnerability, and a sense of family-like connection to other group members.

As a result, strongly fused members become more personal—and powerful—agents of the group. Whether they are fused soldiers, community advocates, or company-men and women, they all share a unique willingness to defend, promote, and seek justice for the group.