This article presents a theory of groups. The theory takes a more molarperspective on groups than has often been the case in group research. It gives special emphasis to temporal processes in group interaction and task performance. The three main sections of the article present the theory as a series of propositions about the nature of groups, temporal processes in group behavior, and temporal aspects of interaction, respectively. The final section presents brief comments on some implications and potential applications of the theory.

A century of research on small groups has yielded bountiful findings about many specific features and processes in groups. Much of that work, in line with a positivist epistemology that emphasizes control and precision and favors the laboratory experiment over other data collection strategies, has also tended to treat groups as though they were simple, isolated, static entities. Recent research trends that treat groups as complex, adaptive, dynamic systems open up new approaches to studying groups. In line with those trends, a theory of groups as complex systems is offered and some methodological and conceptual issues raised by this theory are identified. A 3-pronged research strategy based on theory development, computational modeling, and empirical research that holds promise for illuminating the dynamic processes underlying the emergence of complexity and the ongoing balance of continuity and change in groups is proposed.

We compared the speed and quality of performance for familiar, initially unfamiliar but continuing, and one‐shot (single session) teams. We also proposed and observed entrainment effects for task time limits. Over the course of weekly sessions with changing tasks, continuing teams reached speed levels of the initially familiar teams, but the one‐shot teams were consistently slower. Continuing teams also tended to have higher‐quality output than the one‐shot teams. There were no differences in how quickly each type of group entrained to time limits on the tasks. Entrainment was not robust to task discontinuity (Task A, then B). However, entrainment on repeated trials of a task persisted even when a different type of task “interrupted” those repeated trials (Task A, then B, then A again). Results compel a richer incorporation of time as a medium for complex task sequences, and time‐based constructs as a feature of team membership in the study of group effectiveness.

The authors investigated the hypothesis that as group tasks pose greater requirements for member interdependence, communication media that transmit more social context cues will foster group performance and satisfaction. Seventy-two 3-person groups of undergraduate students worked in either computer-mediated or face-to-face meetings on 3 tasks with increasing levels of interdependence: an idea-generation task, an intellective task, and a judgment task. Results showed few differences between computer-mediated and face-to-face groups in the quality of the work completed but large differences in productivity favoring face-to-face groups. Analysis of productivity and of members' reactions supported the predicted interaction of tasks and media, with greater discrepancies between media conditions for tasks requiring higher levels of coordination. Results are discussed in terms of the implications of using computer-mediated communications systems for group work.

This study examined the effects of time limits and task types on the quality and quantity of group performance and patterns of group interaction. The results were interpreted in terms of social entrainment, a concept that refers to the altering of social “rhythms” or patterns by external conditions (such as time limits), and to the persistence of such new rhythms over time. Groups performed two tasks of a single task type for two trials of different durations (10 min followed by 20 min, or 20 min followed by 10 min). Tasks of three types were used, each requiring an essay-type solution. Task products were assessed on the basis of both quantity and quality dimensions. Measures of group interaction patterns were also taken, by categorizing a systematic time sample of the comments of group members. The results indicated that groups with a 20-min first trial produced products that were higher in both quality and quantity (but not rate), and engaged in proportionally more interpersonal activity during interaction, than did groups that had a 10-min first trial. Further, those same groups persisted in the same patterns of interaction (and, to a much lesser extent, patterns of task performance) on the second trial, despite changes in the time limit on that latter trial.