Some scientific categories seem to correspond to genuine features of the world and are indispensable for successful science in some domain; in short, they are natural kinds. This book gives a general account of what it is to be a natural kind and puts the account to work illuminating numerous specific examples.

Wegner, Giuliano, and Hertel (1985) defined the notion of a transactive memory system (TMS) as a group level memory system that “involves the operation of the memory systems of the individuals and the processes of communication that occur within the group (p. 191). Those processes are the collaborative procedures (“transactions”) by which groups encode, store, and retrieve information that is distributed among their members. Over the past 25+ years, the conception of a TMS has progressively garnered an increased interest among (...) social and organizational psychologists, communication scholars, and management theorists (Ren & Argote 2011). But there remains considerable disagreement about how exactly Wegner’s appeal to group memory should be understood. My goal in this paper is contribute to this debate, by articulating more clearly the value of conceptualizing groups as TMSs. This value, I argue, consists in providing us with a blueprint for how to explain group memory in terms of collective information-processing mechanisms. Collective information-processing mechanisms are dependent on, and interact with, the brain-bound information-processing of individuals, but cannot be reduced to the latter. In my analysis, I lean on extant accounts of mechanistic explanation in the philosophy of science (Bechtel & Richardson 1993; Machamer, Darden, & Craver 2000; Wimsatt 2007) that have been used to analyze the explanatory practices of psychology and cognitive neuroscience (Bechtel 2008, 2009). Based on my reconstruction of Wegner’s conceptualization of a TMS, I argue that the reality of emergent group cognition is compatible with its mechanistic explanation. More generally, my analysis shows that group cognition cannot be reduced to individual cognition, while avoiding the false dilemma between “wholism” and “nothing but-ism” which has hampered traditional construals of the “group mind” thesis (Allport 1968). (shrink)

I start with a brief assessment of the implications of Sterelny’s anti-individualist, anti-internalist apprentice learning model for a more historical and interdisciplinary cognitive science. In a selective response I then focus on two core features of his constructive account: collaboration and skill. While affirming the centrality of joint action and decision making, I raise some concerns about the fragility of the conditions under which collaborative cognition brings benefits. I then assess Sterelny’s view of skill acquisition and performance, which runs counter (...) to dominant theories that stress the automaticity of skill. I suggest that it may still overestimate the need for and ability of experts to decompose and represent the elements of their own practical knowledge. (shrink)

People often talk to others about their personal past. These discussions are inherently selective. Selective retrieval of memories in the course of a conversation may induce forgetting of unmentioned but related memories for both speakers and listeners (Cuc, Koppel, & Hirst, 2007). Cuc et al. (2007) defined the forgetting on the part of the speaker as within-individual retrieval-induced forgetting (WI-RIF) and the forgetting on the part of the listener as socially shared retrieval-induced forgetting (SS-RIF). However, if the forgetting associated with (...) WI-RIF and SS-RIF is to be taken seriously as a mechanism that shapes both individual and shared memories, this mechanism must be demonstrated with meaningful material and in ecologically valid groups. In our first 2 experiments we extended SS-RIF from unemotional, experimenter-contrived material to the emotional and unemotional autobiographical memories of strangers (Experiment 1) and intimate couples (Experiment 2) when merely overhearing the speaker selectively practice memories. We then extended these results to the context of a free-flowing conversation (Experiments 3 and 4). In all 4 experiments we found WI-RIF and SS-RIF regardless of the emotionalvalence or individual ownership of the memories. We discuss our findings in terms of the role of conversational silence in shaping both our personal and shared pasts. (shrink)

To what extent should we focus on implicit bias in order to eradicate persistent social injustice? Structural prioritizers argue that we should focus less on individual minds than on unjust social structures, while equal prioritizers think that both are equally important. This article introduces the framework of transactive memory into the debate to defend the equal priority view. The transactive memory framework helps us see how structure can emerge from individual interactions as an irreducibly social product. If this is right, (...) then debiasing interventions are structural interventions. One upshot is that the utility of the individual versus structural distinction is not apparent for the purposes of intervention. (shrink)

This paper aims to expand the range of empirical work relevant to the extended cognition debates. First, I trace the historical development of the person-situation debate in social and personality psychology and the extended cognition debate in the philosophy of mind. Next, I highlight some instructive similarities between the two and consider possible objections to my comparison. I then argue that the resolution of the person-situation debate in terms of interactionism lends support for an analogously interactionist conception of extended cognition. (...) I argue that this interactionism might necessitate a shift away from the dominant agent-artifact paradigm toward an agent–agent paradigm. If this is right, then social and personality psychology—the discipline(s) that developed from the person-situation debate—opens a whole new range of empirical considerations for extended cognition theorists which align with Clark & Chalmers original vision of agents themselves as spread into the world. (shrink)

I argue that examining the explanatory power of the hypothesis of extended cognition (HEC) offers a fruitful approach to the problem of cognitive system demarcation. Although in the discussions on HEC it has become common to refer to considerations of explanatory power as a means for assessing the plausibility of the extended cognition approach, to date no satisfying account of explanatory power has been presented in the literature. I suggest that the currently most prominent theory of explanation in the special (...) sciences, James Woodward’s contrastive-counterfactual theory, and an account of explanatory virtues building on that theory can be used to develop a systematic picture of cognitive system demarcation in the psychological sciences. A major difference between my differential influence (DI) account and most other theories of cognitive extension is the cognitive systems pluralism implied by my approach. By examining the explanatory power of competing traditions in psychological memory research, I conclude that internalist and externalist classificatory strategies are characterized by different profiles of explanatory virtues and should often be considered as complementary rather than competing approaches. This suggests a deflationary interpretation of HEC. (shrink)

Massive Open Online Courses (MOOCs) have, in recent years, become increasingly popular. An important challenge facing MOOCs is the ‘teacher bandwidth problem’: In the MOOC environment, where there are potentially hundreds of thousands of students, it is impossible for a few teachers to interact with individual students—there is not enough ‘teacher bandwidth’. According to Siemens and Downes’s theory of ‘connectivism’ (Siemens, 2004) one can make up for the lack of teacher bandwidth by relying on collaboration between students; philosophically speaking, however, (...) this theory is underdeveloped. In this paper, we consider the question of learner collaboration in online courses, and the theory of connectivism, from the perspective of social epistemology. We note the similarities between Siemens and Downes’s theory and virtue reliabilist theories of epistemic collaboration more broadly. Our paper has two main aims. First, we offer an illustration of how it is possible to conceptualise learner collaboration in online settings as analogous to collaboration between scientists. Second, we attempt to expand on and clarify what Siemens and Downes had in mind when they proposed the theory of connectivism. (shrink)

The aim of this paper is to demonstrate that the postulation of irreducible, distributed cognitive systems is necessary for the successful explanatory practice of cognitive science and sociology. Towards this end, and with an eye specifically on the phenomenon of distributed cognition, the debate over reductionism versus emergence is examined from the perspective of Dynamical Systems Theory. The motivation for this novel approach is threefold. Firstly, DST is particularly popular amongst cognitive scientists who work on modelling collective behaviors. Secondly, DST (...) can deliver two distinct arguments in support of the claim that the presence of mutual interactions between group members necessitates the postulation of the corresponding group entity. Thirdly, DST can also provide a succinct understanding of the way group entities exert downward causation on their individual members. The outcome is a naturalist account of the emergent, and thereby irreducible, nature of distributed cognitive systems that avoids the reductionists’ threat of epiphenomenalism, while being well in line with materialism. (shrink)

Mainstream epistemologists have recently made a few isolated attempts to demonstrate the particular ways, in which specific types of knowledge are partly social. Two promising cases in point are Lackey’s dualism in the epistemology of testimony and Goldberg’s process reliabilist treatment of testimonial and coverage-support justification. What seems to be missing from the literature, however, is a general approach to knowledge that could reveal the partly social nature of the latter anytime this may be the case. Indicatively, even though Lackey (...) :345–361, 2007) has recently launched an attack against the Credit Account of Knowledge on the basis of testimony, she has not classified her view of testimonial knowledge into any of the alternative, general approaches to knowledge. Similarly, even if Goldberg’s attempt to provide a process reliabilist explanation of the social nature of testimonial knowledge is deemed satisfactory, his attempt to do the same in the case of coverage-support justification does not deliver the requisite result. This paper demonstrates that CAK can in fact provide, pace Lackey’s renunciation of the view, a promising account of the social nature of both testimonial and coverage-supported knowledge. Additionally, however, it can display further explanatory power by also revealing the social nature of knowledge produced on the basis of epistemic artifacts. Despite their disparities, all these types of knowledge count as partly social in nature, because in all these cases, according to CAK, the epistemic credit for the individual agent’s true belief must spread between the individual agent and certain parts of her epistemic community. Accordingly, CAK is a promising candidate for providing a unified approach to several and, perhaps all possible, instances of what we may call ‘weak epistemic anti-individualism’ within mainstream epistemology: i.e., the claim that the nature of knowledge can occasionally be both social and individual at the same time. (shrink)

In Weaving the Web, Berners-Lee defines Social Machines as biotechnologically hybrid Web-processes on the basis of which, “high-level activities, which have occurred just within one human’s brain, will occur among even larger more interconnected groups of people acting as if the shared a larger intuitive brain”. The analysis and design of Social Machines has already started attracting considerable attention both within the industry and academia. Web science, however, is still missing a clear definition of what a Social Machine is, which (...) has in turn resulted in several calls for a “philosophical engineering” ; Halpin et al. 2010). This paper is a first attempt to respond to this call, by combining contemporary philosophy of mind and cognitive science with epistemology. The idea of philosophical engineering implies that a sufficiently good conception of Social Machines should be of both theoretical and practical advantage. To demonstrate how the present approach can satisfy both objectives it will be used in order to address one of Wikipedia’s most worrying concerns—i.e., the current and ongoing decline in the number of its active contributors. (shrink)

Within analytic philosophy, the existence of collective knowledge has been motivated by means of two apparently distinct, and in direct competition with one another, theoretical approaches: (i) the commitment model and (ii) the distributed model. This paper agues, however, that to fully account for collaborative knowledge—i.e., a special kind of collective knowledge—both models are required. In other words, there is at least one kind of collective knowledge, the account of which requires treating the two models not as competitors but as (...) complementary to each other. If that’s correct, not only can we gain a deeper understanding of the specifics surrounding collaborative knowledge but also a clearer picture of the broader debate surrounding collective knowledge. (shrink)

According to the hypotheses of distributed and extended cognition, remembering does not always occur entirely inside the brain but is often distributed across heterogeneous systems combining neural, bodily, social, and technological resources. These ideas have been intensely debated in philosophy, but the philosophical debate has often remained at some distance from relevant empirical research, while empirical memory research, in particular, has been somewhat slow to incorporate distributed/extended ideas. This situation, however, appears to be changing, as we witness an increasing level (...) of interaction between the philosophy and the empirical research. In this editorial, we provide a high-level historical overview of the development of the debates around the hypotheses of distributed and extended cognition, as well as relevant theory and empirical research on memory, considering both the role of memory in theoretical debates around distributed/extended ideas and strands of memory research that resonate with those ideas; we emphasize recent trends towards increased interaction, including new empirical paradigms for investigating distributed memory systems. We then provide an overview of the special issue itself, drawing out a number of general implications from the contributions, and conclude by sketching promising directions for future research on distributed memory. (shrink)

Memory technologies are cultural artifacts that scaffold, transform, and are interwoven with human biological memory systems. The goal of this article is to provide a systematic and integrative survey of their philosophical dimensions, including their metaphysical, epistemological and ethical dimensions, drawing together debates across the humanities, cognitive sciences, and social sciences. Metaphysical dimensions of memory technologies include their function, the nature of their informational properties, ways of classifying them, and their ontological status. Epistemological dimensions include the truth-conduciveness of external memory, (...) the conditions under which external memory counts as knowledge, and the metacognitive monitoring of external memory processes. And lastly, ethical and normative dimensions include the desirability of the effects memory technologies have on biological memory, their effects on self and culture, and their moral status. Whilst the focus in the article is largely philosophical and conceptual, empirical issues such as the way we interact with memory technologies in various contexts are also discussed. We thus take a naturalistic approach in which philosophical and empirical concepts and approaches are seen as continuous. (shrink)

This paper explores the implications of extended and distributed cognition theory for our notions of personal identity. On an extended and distributed approach to cognition, external information is under certain conditions constitutive of memory. On a narrative approach to personal identity, autobiographical memory is constitutive of our diachronic self. In this paper, I bring these two approaches together and argue that external information can be constitutive of one’s autobiographical memory and thus also of one’s diachronic self. To develop this claim, (...) I draw on recent empirical work in human-computer interaction, looking at lifelogging technologies in both healthcare and everyday contexts. I argue that personal identity can neither be reduced to psychological structures instantiated by the brain nor by biological structures instantiated by the organism, but should be seen as an environmentally-distributed and relational construct. In other words, the complex web of cognitive relations we develop and maintain with other people and technological artifacts partly determines our self. This view has conceptual, methodological, and normative implications: we should broaden our concepts of the self as to include social and artifactual structures, focus on external memory systems in the (empirical) study of personal identity, and not interfere with people’s distributed minds and selves. (shrink)

In the history of external information systems, the World Wide Web presents a significant change in terms of the accessibility and amount of available information. Constant access to various kinds of online information has consequences for the way we think, act and remember. Philosophers and cognitive scientists have recently started to examine the interactions between the human mind and the Web, mainly focussing on the way online information influences our biological memory systems. In this article, we use concepts from the (...) extended cognition and distributed cognition frameworks and from transactive memory theory to analyse the cognitive relations between humans and the Web. We first argue that while neither of these approaches neatly capture the nature of human-Web interactions, both offer useful concepts to describe aspects of such interactions. We then conceptualize relations between the Web and its users in terms of cognitive integration, arguing that most current Web applications are not deeply integrated and are better seen as a scaffold for memory and cognition. Some highly personalised applications accessed on wearable computing devices, however, may already have the capacity for deep integration. Finally, we draw out some of the epistemic implications of our cognitive analysis. (shrink)

This paper introduces a new, expanded range of relevant cognitive psychological research on collaborative recall and social memory to the philosophical debate on extended and distributed cognition. We start by examining the case for extended cognition based on the complementarity of inner and outer resources, by which neural, bodily, social, and environmental resources with disparate but complementary properties are integrated into hybrid cognitive systems, transforming or augmenting the nature of remembering or decision-making. Adams and Aizawa, noting this distinctive complementarity argument, (...) say that they agree with it completely: but they describe it as “a non-revolutionary approach” which leaves “the cognitive psychology of memory as the study of processes that take place, essentially without exception, within nervous systems.” In response, we carve out, on distinct conceptual and empirical grounds, a rich middle ground between internalist forms of cognitivism and radical anti-cognitivism. Drawing both on extended cognition literature and on Sterelny’s account of the “scaffolded mind” (this issue), we develop a multidimensional framework for understanding varying relations between agents and external resources, both technological and social. On this basis we argue that, independent of any more “revolutionary” metaphysical claims about the partial constitution of cognitive processes by external resources, a thesis of scaffolded or distributed cognition can substantially influence or transform explanatory practice in cognitive science. Critics also cite various empirical results as evidence against the idea that remembering can extend beyond skull and skin. We respond with a more principled, representative survey of the scientific psychology of memory, focussing in particular on robust recent empirical traditions for the study of collaborative recall and transactive social memory. We describe our own empirical research on socially distributed remembering, aimed at identifying conditions for mnemonic emergence in collaborative groups. Philosophical debates about extended, embedded, and distributed cognition can thus make richer, mutually beneficial contact with independently motivated research programs in the cognitive psychology of memory. (shrink)

Ouraiminthischapteristodelineatetheformofsharedagencythatwe take to be manifested in collective memory. We argue for two theses. First, we argue that, given a relatively weak conception of episodicity, certain small-scale groups display a form of emergent (i.e., genuinely collective) episodic memory, while large-scale groups, in contrast, do not display emergent episodic memory. Second, we argue that this form of emergent memory presupposes (high-level and possibly low-level) metamemorial capacities, capacities that are, however, not themselves emergent group-level features but rather strictly individual-level features. The form of (...) shared agency that we delineate is thus revealed as being minimal in three senses. First, the relevant groups are themselves minimal in terms of their size. Second, the form of memory in question is minimally episodic. And finally, the cognitive capac- ities attributed to the relevant groups are minimal, in the sense that they need not themselves be capable of metacognition. (shrink)

Recalling autobiographical memories with others can influence the quality of recall, but little is known about how features of the group influence memory outcomes. In two studies, we examined how the products and processes of autobiographical recall depend on individual vs. collaborative remembering and the relationship between group members. In both studies, dyads of strangers, friends, and siblings recalled autobiographical events individually (elicitation), then either collaboratively or individually (recall). Study 1 involved typing memory narratives; Study 2 involved recalling aloud. We (...) examined shifts in vividness, emotionality, and pronoun use within memory narratives produced by different relationship types. In Study 2, we also coded collaborative dyads’ “collaborative processes” or communication processes. In Study 1, all relationships showed decreased positive emotion and I-pronouns and increased negative emotion within collaboratively-produced memory narratives. In Study 2, all relationships showed increased vividness, reduced emotionality and positive and negative emotion, and increased I- and we-pronouns within collaborativelyproduced memory narratives. However, strangers used collaborative processes differently from friends and siblings. Some collaborative processes were associated with memory qualities. Across studies, collaboration influenced memory quality more than did relationship type, but relationship type influenced dyads’ recall dynamics. These findings indicate the complexity of social influences on memory. (shrink)

We often remember in the company of others. In particular, we routinely collaborate with friends, family, or colleagues to remember shared experiences. But surprisingly, in the experimental collaborative recall paradigm, collaborative groups remember less than their potential, an effect termed collaborative inhibition. Rajaram and Pereira-Pasarin (2010) argued that the effects of collaboration on recall are determined by “pre-collaborative” factors. We studied the role of 2 pre-collaborative factors—shared encoding and group relationship—in determining the costs and benefits of collaborative recall. In Experiment (...) 1, we compared groups of strangers who encoded alone versus together, before collaborating to recall. In Experiment 2, we compared groups of friends who encoded alone versus together, before collaborating to recall. We found that shared encoding abolished collaborative inhibition in both Experiments 1 and 2. But prior relationship did not influence collaborative inhibition over and above the effects of shared encoding. Regardless of encoding condition, collaborative group recall contained fewer intrusions than nominal group recall, and these benefits continued in subsequent individual recall. Our findings demonstrate that pre-collaborative factors—specifically shared encoding—have flow-on benefits for group and individual recall amount, but not recall accuracy. We discuss these findings in terms of self- and cross-cuing in collaborative recall. (shrink)

Experimental memory research has traditionally focused on the individual, and viewed social influence as a source of error or inhibition. However, in everyday life, remembering is often a social activity, and theories from philosophy and psychology predict benefits of shared remembering. In a series of studies, both experimental and more qualitative, we attempted to bridge this gap by examining the effects of collaboration on memory in a variety of situations and in a variety of groups. We discuss our results in (...) terms of a functional view of collaborative remembering, and consider when and in what ways remembering with others might help or hinder memory. (shrink)

We show how an epistemology informed by cognitive science promises to shed light on an ancient problem in the philosophy of mathematics: the problem of exactness. The problem of exactness arises because geometrical knowledge is thought to concern perfect geometrical forms, whereas the embodiment of such forms in the natural world may be imperfect. There thus arises an apparent mismatch between mathematical concepts and physical reality. We propose that the problem can be solved by emphasizing the ways in which the (...) brain can transform and organize its perceptual intake. It is not necessary for a geometrical form to be perfectly instantiated in order for perception of such a form to be the basis of a geometrical concept. (shrink)

Collective memory researchers predominantly in the cultural and social sciences have commonly understood the concept of collective memory as a mere metaphor, as something not existing in itself as memory but useful only as a tool for referring to the way groups construct shared representations of their past. Few have however addressed the question of whether it is a metaphor or literal in its own right. This paper looks at the plausibility of the claim that collective memory is a mere (...) metaphor by probing its presuppositions, where the representationalist theory of mind emerges as the ground for such a claim. Then appealing to the externalist model of the mind championed in recent studies of mind in disciplines as varied as philosophy, cognitive science, evolutionary biology, and collective intentionality studies, we try to expose the presuppositions of that claim, opening up possibilities for conceiving collective memory as not merely metaphorical but literal and naturally existing as memory. (shrink)

Cooperation admits of degrees. When factory workers stage a slowdown, they do not cease to cooperate with management in the production of goods altogether, but they are not fully cooperative either. Full cooperation implies that participants in a joint action are committed to rendering appropriate contributions as needed toward their joint end so as to bring it about, consistently with the type of action and the generally agreed upon constraints within which they work, as efficiently as they can, where their (...) contributions are sensitive to information (where available) about how others are contributing in the sense that they adjust as needed their contributions in light of information about how others are contributing to ensure effective pursuit of their joint end, where this includes rendering aid to other participants if needed, insofar as they are able. Full cooperation entails those cooperating are engaged in a joint intentional action. Some prominent studies of joint intentional action focus exclusively on cases of full cooperation (notably that of Michael Bratman (2014)). But not all joint intentional action is fully cooperative. One example is the work slowdown. Another example is provided by competitive games like chess and football, or sports like boxing and wrestling, where participants are clearly not intending to contribute to the pursuit of all of the goals of the others engaged in the activity, even when those goals are internal to the type of activity in question, but instead intend actively to frustrate some of them. In this paper, I provide a taxonomy of forms of non-cooperative behavior within the context of behavior that is still to some degree cooperative, and I argue that the minimal conditions of joint intentional action define minimal cooperative behavior, that is, that minimally joint intentional action is per se minimally cooperative behavior. I define in precise terms what that comes to, and how it is possible in cases in which it seems that one or more participants are in one or more ways acting so as to frustrate the contributions of other participants to their joint action. (shrink)

Being social creatures in a complex world, we do things together. We act jointly. While cooperation, in its broadest sense, can involve merely getting out of each other’s way, or refusing to deceive other people, it is also essential to human nature that it involves more active forms of collaboration and coordination (Tomasello 2009; Sterelny 2012). We collaborate with others in many ordinary activities which, though at times similar to those of other animals, take unique and diverse cultural and psychological (...) forms in human beings. But we also work closely and interactively with each other in more peculiar and flexible practices which are in distinctive ways both species-specific and culturally and historically contingent: from team sports to shared labour, from committee work to mass demonstrations, from dancing to reminiscing together about old times. (shrink)

In this paper, we aim to show that the framework of embedded, distributed, or extended cognition offers new perspectives on social cognition by applying it to one specific domain: the psychology of memory. In making our case, first we specify some key social dimensions of cognitive distribution and some basic distinctions between memory cases, and then describe stronger and weaker versions of distributed remembering in the general distributed cognition framework. Next, we examine studies of social influences on memory in cognitive (...) psychology, and identify the valuable concepts and methods to be extended and embedded in our framework; we focus in particular on three related paradigms: transactive memory, collaborative recall, and social contagion. Finally, we sketch our own early studies of individual and group memory developed within our framework of distributed cognition, on social contagion of autobiographical memories, collaborative flashbulb memories, and memories of high school at a high school reunion. We see two reciprocal benefits of this conceptual and empirical framework to social memory phenomena: that ideas about distributed cognition can be honed against and tested with the help of sophisticated methods in the social cognitive psychology of memory; and conversely, that a range of social memory phenomena that are as yet poorly understood can be approached afresh with theoretically motivated extensions of existing empirical paradigms. (shrink)

We have a striking ability to alter our psychological access to past experiences. Consider the following case. Andrew “Nicky” Barr, OBE, MC, DFC, (1915 – 2006) was one of Australia’s most decorated World War II fighter pilots. He was the top ace of the Western Desert’s 3 Squadron, the pre-eminent fighter squadron in the Middle East, flying P-40 Kittyhawks over Africa. From October 1941, when Nicky Barr’s war began, he flew 22 missions and shot down eight enemy planes in his (...) first 35 operational hours. He was shot down three times, once 25 miles behind enemy lines while trying to rescue a downed pilot. He escaped from prisoner of war camps four times, once jumping out of a train as it travelled from Italy into Austria. His wife Dot, who he married only weeks before the war, waited for him at home. She was told on at least three occasions that he was missing in action or dead. For 50 years, Nicky Barr never spoke publicly, and rarely privately, of his war-time experiences. He was very much a forgotten and forgetting hero (for further details, see Dornan, 2002). In his first public interview in 2002 on the Australian documentary program “Australian Story”, Nicky explained his 50 year silence by saying. (shrink)

Philip Robbins and Murat Aydede (eds), The Cambridge Handbook of Situated Cognition (Cambridge University Press, 2009), 217-235.

Very often our memories of the past are of experiences or events we shared with others. And ‘‘in many circumstances in society, remembering is a social event’’ (Roediger, Bergman, & Meade, 2000, p. 129): parents and children reminisce about significant family events, friends discuss a movie they just saw together, students study for exams with their roommates, colleagues remind one another of information relevant to an important group decision, and complete strangers discuss a crime they happened to witness together. Psychology (...) is at the heart of recent interdisciplinary efforts to understand the relationships between an individual remembering alone, an individual remembering in a group, and the group itself remembering. (shrink)