Neurocognitive mechanisms of collaborative recall.

Research on collaborative memory shows that people recalling in groups rarely achieve optimal performance. Collaborative groups typically recall less than nominal groups, where performance for the latter is derived by pooling the non-overlapping information recalled by the same number of individuals working alone. While behavioural evidence has widely replicated this collaborative inhibition in free recall, little evidence speaks to the neurophysiological signatures of this counterintuitive phenomenon. Behavioural evidence also indicates that disruption to one's preferred recall strategy, resulting from processing others' recalled information, is a key mechanism underlying this effect. We aimed to identify the neural signatures indexing the recollection process and their disruption during collaborative recall. In three experiments, we replicated the standard collaborative inhibition effect with an EEG-adapted procedure (Experiment 1), and recorded EEG while people recalled in groups or in isolation (Experiments 2a, 2b). Comparisons showed increments in N400 and theta power, the neurophysiological components associated with interference, at shorter intervals for the collaborative compared to the nominal groups. Stronger theta power for collaborative than nominal recall, and for speakers than non-speakers in collaborative groups, were also evident at longer intervals and suggest demanding reinstatement of memory associated with collaborative recall. Together, the results suggest distinct neural processes underlying collaborative inhibition, with neural responses at shorter intervals signaling processes that are consistent with strategy disruption (stronger interference signaled by N400 and theta power increments), and further increments in theta at later times suggesting more demanding reinstatement processes during collaborative remembering.

Persistence of false memories and emergence of collective false memory: collaborative recall of DRM word lists.

Information and misinformation are proliferating on social media. A rapid rise in the use of these platforms makes it important to identify psychological mechanisms that underlie the production, propagation, and convergence of false memories in groups. Websites and social media platforms vary in the extent of restrictions placed on interactive communication (e.g., group chats, threaded or disabled comments, direct messaging), prompting questions about the impact of different interaction styles on false memory production. We tested this question in a laboratory analog of interaction styles and compared two well-known procedures of collaboration, free-for-all and turn-taking. To expose participants to information known to promote recall of both true and false information, we used the Deese-Roediger-McDermott (DRM) word lists (Roediger & McDermott, 1995). Participants recalled these words using free-for-all collaboration, turn-taking collaboration, or individually. Next, all participants individually recalled the studied items. Turn-taking produced more false memories in group recall than did free-for-all collaboration, replicating past findings. Novel findings showed that former group members exhibited social contagion following both interaction styles, where they produced more false information in later individual recall and exhibited collective false memories. We discuss the implications for the emergence and convergence of true and false memories among users online.

When social influences reduce false recognition memory: A case of categorically related information.

Social interactions create opportunities for reminiscence and memory rehearsal but can also lead to memory errors. We tested how the type of information people remember can influence the magnitude of memory errors they make following collaborative discussion. Past findings show that unrelated item lists and emotional salient items reduce false alarms and improve memory discrimination, respectively, on an individual recognition test after collaborative discussion compared to no prior collaboration. In contrast, for associatively related materials with high relatedness (e.g., bed, rest, awake, tired, dream, etc.) collaboration increases false recognition memory for the critical lures (e.g., sleep) on a later individual test. We tested whether the error-pruning benefits of collaboration are restricted to unrelated and emotional information or can also occur for other classes of related information that produce high memory errors. Using categorized stimuli, we created conditions that produced high or low memory errors for the same targets (12 versus 2 target exemplars per category across study lists of equal length). Replicating past research, collaboration increased the accuracy of recognition memory and large category size decreased it. The critical novel finding showed that collaboration pruned individual recognition errors by reducing false alarms not only in the low memory error condition but also the high memory error condition. This study delineates the conditions where collaboration can prune memory errors for related information.

Social Transmission of False Memory in Small Groups and Large Networks.

Sharing information and memories is a key feature of social interactions, making social contexts important for developing and transmitting accurate memories and also false memories. False memory transmission can have wide-ranging effects, including shaping personal memories of individuals as well as collective memories of a network of people. This paper reviews a collection of key findings and explanations in cognitive research on the transmission of false memories in small groups. It also reviews the emerging experimental work on larger networks and collective false memories. Given the reconstructive nature of memory, the abundance of misinformation in everyday life, and the variety of social structures in which people interact, an understanding of transmission of false memories has both scientific and societal implications.

Collaborative remembering of emotional autobiographical memories: Implications for emotion regulation and collective memory.

People frequently engage in conversation about shared autobiographical events from their lives, particularly those with emotional significance. The pervasiveness of this practice raises the question whether shared memory reconstruction has the power to influence the memory and emotions associated with such events. We developed a novel paradigm that combined the strengths of the methods from autobiographical and collaborative memory research traditions to examine such consequences. We selected a shared, real-life autobiographical event of an exam, and asked students to recall their memory of taking a recent exam where they provided a group and/or personal narrative of this autobiographical event. Students first recalled the event either collaboratively (C) or individually (I), followed by a final individual (I) recall by all. Valence ratings as well as the emotional tone of the narratives converged to show that prior collaborative remembering down-regulated negative emotion and enhanced the positive emotional tone of the memories. The recalled detail in the narratives indicated that at initial recall members of collaborative groups reported fewer internal details than those who recalled alone, and reported more external details in a later recall when working alone. Earlier collaboration also increased collective memory such that more of these details were shared among prior group members in their later individual recall compared with those who did not collaborate before. We discuss the influence of collaborative remembering on shaping memory and emotion for autobiographical events as well as the potential mechanisms that promote collective autobiographical memory. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Happiness increases verbal and spatial working memory capacity where sadness does not: Emotion, working memory and executive control.

The effects of emotion on working memory and executive control are often studied in isolation. Positive mood enhances verbal and impairs spatial working memory, whereas negative mood enhances spatial and impairs verbal working memory. Moreover, positive mood enhances executive control, whereas negative mood has little influence. We examined how emotion influences verbal and spatial working memory capacity, which requires executive control to coordinate between holding information in working memory and completing a secondary task. We predicted that positive mood would improve both verbal and spatial working memory capacity because of its influence on executive control. Positive, negative and neutral moods were induced followed by completing a verbal (Experiment 1) or spatial (Experiment 2) working memory operation span task to assess working memory capacity. Positive mood enhanced working memory capacity irrespective of the working memory domain, whereas negative mood had no influence on performance. Thus, positive mood was more successful holding information in working memory while processing task-irrelevant information, suggesting that the influence mood has on executive control supersedes the independent effects mood has on domain-specific working memory.