Member differentiation
A fundamental assumption of the target article is that members must be differentiated, or individuated, if the group is to succeed in achieving virtually any collective goal (though some possible exceptions are briefly noted). The authors adopt a very flexible definition of differentiation, which includes making a publicly identifiable task contribution, receiving reward contingent on one's contribution, feeling accountable for one's contribution (via the need to justify it to others), providing an independent judgment on a collective decision-making task, and playing a distinct role in a task that requires division of labor. These various types of differentiation are treated interchangeably throughout the target article. Although aggregating diverse definitions of a construct has potential benefits (in this case, differentiation), it also comes with potential costs. The major benefit is identifying commonalities across definitions, which can facilitate development of a comprehensive theory. The major cost is obscuring important distinctions between definitions, which can retard theory development.
With one major exception, the various definitions of differentiation in the target article involve a common psychological process, namely evaluative apprehension about how other group members will assess and respond to one's contribution. The exception is playing a distinct role in a division-of-labor task. Inclusion of this latter definition raises an important question about how the authors conceptualize differentiation, which has implications for their overall analysis. The question is whether differentiation is a subjective or an objective phenomenon, that is, whether it refers to the extent to which group members (a) feel pressure to behave as others might wish or (b) differ in skills, knowledge, opinions, and so forth, that enable them to play complementary roles on tasks requiring specialization and coordination. Because these two forms of differentiation are potentially orthogonal (and different combinations of subjective and objective differentiation might have different effects on group performance), subsuming them both under the label of differentiation is problematical. In particular, given that the bulk of the target article deals with subjective differentiation, inclusion of objective differentiation vis-à-vis division-of-labor tasks muddies the conceptual waters. Therefore, my comments below are restricted to subjective differentiation and its implications for evaluative apprehension.
Group tasks
To their credit, Baumeister et al. recognize that the impact of differentiation depends on the type of task the group is working on. They identify three categories of tasks in which public and private subjective differentiation might influence group effectiveness: (1) task performance (also called productive achievement tasks), subsuming social facilitation and social loafing (and ignoring division of labor for reasons mentioned above); (2) information, judgment, and decision (also called information use tasks), subsuming information pooling, brainstorming, conformity, groupthink, accountability, and wise groups; and (3) prosocial and antisocial behavior, subsuming social dilemmas and mob violence. Their literature review suggests that public differentiation (which increases evaluation apprehension) improves group performance on productive achievement tasks and facilitates prosocial behavior/inhibits antisocial behavior. In contrast, private differentiation (which decreases evaluation apprehension) improves group performance on information use tasks.
This analysis, though interesting, is weakened by the absence of a persuasive rationale for the tripartite task typology. Rather than adopting (or adapting) one of the many extant group task typologies (e.g., McGrath Reference McGrath1984; Steiner Reference Steiner1972), for reasons that are not clear Baumeister et al. settled on the three categories I described above. The absence of a strong conceptual basis for parsing the task universe into these categories makes it difficult to draw theoretically satisfying conclusions about psychological mechanisms underlying the relationships between public and private differentiation, on the one hand, and group effectiveness, on the other hand.
An alternative typology
To clarify these mechanisms, I suggest an alternative typology of group tasks focusing on norms. Two categories of such norms are viable candidates for organizing the literature Baumeister et al. reviewed. One category prescribes that group members behave in a specified way (e.g., work hard, cooperate with others). The second category prescribes that group members act in accord with their inner states (e.g., express their opinion irrespective of what others say). Work on social facilitation and loafing, accountability, and social dilemmas fits well into the first category, where public differentiation has positive consequences. Work on information pooling, brainstorming, conformity, groupthink, and wise groups fits well into the second category, where private differentiation has positive consequences. (Work on aggression and mob violence can be forced into the first category, but doing so is probably not a good idea for two reasons. First, there are substantial differences between the large, poorly circumscribed aggregates that engage in such behavior and the small task-focused groups featured in the remainder of the target article. Second, defining “group performance” is much more difficult for aggression and mob violence than for the other kinds of group activity Baumeister et al. discuss.)
Conclusion
Baumeister et al. make a useful contribution by focusing attention on the complementary effects of members' shared social identity and their personal characteristics (e.g., skills, knowledge, opinions) on group performance. However, their analysis would be improved by distinguishing between subjective and objective forms of member differentiation and by utilizing a typology of group tasks based on norms.
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This ambitious article analyzes how similarities and differences between group members influence collective performance. The basic premises of the article, listed below, are uncontroversial:
Shared social identity is necessary, but not sufficient, for group effectiveness.
Resources (e.g., knowledge, skills) that members bring to the group are critical, and different members often bring different resources.
To optimize group performance, members' inputs must be coordinated.
The nature of the group task strongly influences the impact of member similarity and difference on collective performance.
Notwithstanding the plausibility of these premises, two features of the authors' analysis can be questioned. The first concerns their definition of member differentiation, which is a key construct in the paper. The second concerns the typology of group tasks they use to organize their literature review.
Member differentiation
A fundamental assumption of the target article is that members must be differentiated, or individuated, if the group is to succeed in achieving virtually any collective goal (though some possible exceptions are briefly noted). The authors adopt a very flexible definition of differentiation, which includes making a publicly identifiable task contribution, receiving reward contingent on one's contribution, feeling accountable for one's contribution (via the need to justify it to others), providing an independent judgment on a collective decision-making task, and playing a distinct role in a task that requires division of labor. These various types of differentiation are treated interchangeably throughout the target article. Although aggregating diverse definitions of a construct has potential benefits (in this case, differentiation), it also comes with potential costs. The major benefit is identifying commonalities across definitions, which can facilitate development of a comprehensive theory. The major cost is obscuring important distinctions between definitions, which can retard theory development.
With one major exception, the various definitions of differentiation in the target article involve a common psychological process, namely evaluative apprehension about how other group members will assess and respond to one's contribution. The exception is playing a distinct role in a division-of-labor task. Inclusion of this latter definition raises an important question about how the authors conceptualize differentiation, which has implications for their overall analysis. The question is whether differentiation is a subjective or an objective phenomenon, that is, whether it refers to the extent to which group members (a) feel pressure to behave as others might wish or (b) differ in skills, knowledge, opinions, and so forth, that enable them to play complementary roles on tasks requiring specialization and coordination. Because these two forms of differentiation are potentially orthogonal (and different combinations of subjective and objective differentiation might have different effects on group performance), subsuming them both under the label of differentiation is problematical. In particular, given that the bulk of the target article deals with subjective differentiation, inclusion of objective differentiation vis-à-vis division-of-labor tasks muddies the conceptual waters. Therefore, my comments below are restricted to subjective differentiation and its implications for evaluative apprehension.
Group tasks
To their credit, Baumeister et al. recognize that the impact of differentiation depends on the type of task the group is working on. They identify three categories of tasks in which public and private subjective differentiation might influence group effectiveness: (1) task performance (also called productive achievement tasks), subsuming social facilitation and social loafing (and ignoring division of labor for reasons mentioned above); (2) information, judgment, and decision (also called information use tasks), subsuming information pooling, brainstorming, conformity, groupthink, accountability, and wise groups; and (3) prosocial and antisocial behavior, subsuming social dilemmas and mob violence. Their literature review suggests that public differentiation (which increases evaluation apprehension) improves group performance on productive achievement tasks and facilitates prosocial behavior/inhibits antisocial behavior. In contrast, private differentiation (which decreases evaluation apprehension) improves group performance on information use tasks.
This analysis, though interesting, is weakened by the absence of a persuasive rationale for the tripartite task typology. Rather than adopting (or adapting) one of the many extant group task typologies (e.g., McGrath Reference McGrath1984; Steiner Reference Steiner1972), for reasons that are not clear Baumeister et al. settled on the three categories I described above. The absence of a strong conceptual basis for parsing the task universe into these categories makes it difficult to draw theoretically satisfying conclusions about psychological mechanisms underlying the relationships between public and private differentiation, on the one hand, and group effectiveness, on the other hand.
An alternative typology
To clarify these mechanisms, I suggest an alternative typology of group tasks focusing on norms. Two categories of such norms are viable candidates for organizing the literature Baumeister et al. reviewed. One category prescribes that group members behave in a specified way (e.g., work hard, cooperate with others). The second category prescribes that group members act in accord with their inner states (e.g., express their opinion irrespective of what others say). Work on social facilitation and loafing, accountability, and social dilemmas fits well into the first category, where public differentiation has positive consequences. Work on information pooling, brainstorming, conformity, groupthink, and wise groups fits well into the second category, where private differentiation has positive consequences. (Work on aggression and mob violence can be forced into the first category, but doing so is probably not a good idea for two reasons. First, there are substantial differences between the large, poorly circumscribed aggregates that engage in such behavior and the small task-focused groups featured in the remainder of the target article. Second, defining “group performance” is much more difficult for aggression and mob violence than for the other kinds of group activity Baumeister et al. discuss.)
Conclusion
Baumeister et al. make a useful contribution by focusing attention on the complementary effects of members' shared social identity and their personal characteristics (e.g., skills, knowledge, opinions) on group performance. However, their analysis would be improved by distinguishing between subjective and objective forms of member differentiation and by utilizing a typology of group tasks based on norms.