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Toward a Neural Basis for Social Behavior

2013; Cell Press; Volume: 80; Issue: 3 Linguagem: Inglês

10.1016/j.neuron.2013.10.038

1097-4199

Damian Stanley, Ralph Adolphs,

Action Observation and Synchronization

Nearly 25 years ago, the shared interests of psychologists and biologists in understanding the neural basis of social behavior led to the inception of social neuroscience. In the past decade, this field has exploded, in large part due to the infusion of studies that use fMRI. At the same time, tensions have arisen about how to prioritize a diverse range of questions and about the authority of neurobiological data in answering them. The field is now poised to tackle some of the most interesting and important questions about human and animal behavior but at the same time faces uncertainty about how to achieve focus in its research and cohesion among the scientists who tackle it. The next 25 years offer the opportunity to alleviate some of these growing pains, as well as the challenge of answering large questions that encompass the nature and bounds of diverse social interactions (in humans, including interactions through the internet); how to characterize, and treat, social dysfunction in psychiatric illness; and how to compare social cognition in humans with that in other animals. Nearly 25 years ago, the shared interests of psychologists and biologists in understanding the neural basis of social behavior led to the inception of social neuroscience. In the past decade, this field has exploded, in large part due to the infusion of studies that use fMRI. At the same time, tensions have arisen about how to prioritize a diverse range of questions and about the authority of neurobiological data in answering them. The field is now poised to tackle some of the most interesting and important questions about human and animal behavior but at the same time faces uncertainty about how to achieve focus in its research and cohesion among the scientists who tackle it. The next 25 years offer the opportunity to alleviate some of these growing pains, as well as the challenge of answering large questions that encompass the nature and bounds of diverse social interactions (in humans, including interactions through the internet); how to characterize, and treat, social dysfunction in psychiatric illness; and how to compare social cognition in humans with that in other animals. We live in a world that is largely socially constructed, our lives are replete with social interactions every day, and it has been suggested that an understanding of our social behavior could answer questions about who we are, how we differ from other animals, and what defines the nature of our conscious experience. Moreover, the importance of social encounters is ubiquitous across all animal species. These facts together with our intense personal interest in the behaviors and minds of other people have spawned a rich and long history of investigation in the social sciences. Recently, these investigations incorporated neurobiological tools, giving birth to the field of social neuroscience. But what exactly is social neuroscience? It encompasses all levels of biological analysis (genetic polymorphisms, neurotransmitters, circuits and systems, as well as collective behavior in groups) and stages of processing (sensory systems, perception, judgment, regulation, decision-making, action), a diversity often emphasized in overviews of the field (Adolphs, 2010Adolphs R. Conceptual challenges and directions for social neuroscience.Neuron. 2010; 65: 752-767Abstract Full Text Full Text PDF PubMed Scopus (194) Google Scholar, Cacioppo et al., 2001Cacioppo J.T. Berntson G.G. Adolphs R. Carter C.S. Davidson R.J. McClintock M.K. McEwen B.S. Meaney M.J. Schacter D.L. Sternberg E.M. Foundations in Social Neuroscience. MIT Press, Cambridge, MA2001Google Scholar). A principled definition of social neuroscience thus begins by saying that it is the study of the neural basis of social behavior and then elaborates from there. However, this elaboration leaves open a wide range of methods to be employed, species to be studied, and theoretical frameworks to anchor the findings, with disagreements about the relative merits of all of these components. These disagreements are reflected in the priorities of faculty searches, funding agencies, and journal publications. The term "social neuroscience" was first coined in the early 1990s (Cacioppo and Berntson, 1992Cacioppo J.T. Berntson G.G. Social psychological contributions to the decade of the brain. Doctrine of multilevel analysis.Am. Psychol. 1992; 47: 1019-1028Crossref PubMed Scopus (292) Google Scholar, Cacioppo et al., 2001Cacioppo J.T. Berntson G.G. Adolphs R. Carter C.S. Davidson R.J. McClintock M.K. McEwen B.S. Meaney M.J. Schacter D.L. Sternberg E.M. Foundations in Social Neuroscience. MIT Press, Cambridge, MA2001Google Scholar) in reference to a fledgling movement that emphasized a broad and multilevel approach to the study of the neural basis of social behavior (see Lieberman, 2012Lieberman M.D. A geographical history of social cognitive neuroscience.Neuroimage. 2012; 61: 432-436Crossref PubMed Scopus (17) Google Scholar and Singer, 2012Singer T. The past, present and future of social neuroscience: a European perspective.Neuroimage. 2012; 61: 437-449Crossref PubMed Scopus (75) Google Scholar for historical overviews from both American and European perspectives). This gestation was accompanied by a proposal that social processing in primates was subserved by a specific brain system (Brothers, 1990Brothers L. The social brain: a project for integrating primate behavior and neurophysiology in a new domain.Concepts Neurosci. 1990; 1: 27-51Google Scholar), as well as by initial neuroimaging studies of social cognition in humans using PET (Fletcher et al., 1995Fletcher P.C. Happé F. Frith U. Baker S.C. Dolan R.J. Frackowiak R.S. Frith C.D. Other minds in the brain: a functional imaging study of "theory of mind" in story comprehension.Cognition. 1995; 57: 109-128Crossref PubMed Scopus (1148) Google Scholar, Happé et al., 1996Happé F. Ehlers S. Fletcher P. Frith U. Johansson M. Gillberg C. Dolan R. Frackowiak R. Frith C. 'Theory of mind' in the brain. Evidence from a PET scan study of Asperger syndrome.Neuroreport. 1996; 8: 197-201Crossref PubMed Scopus (480) Google Scholar, Morris et al., 1996Morris J.S. Frith C.D. Perrett D.I. Rowland D. Young A.W. Calder A.J. Dolan R.J. A differential neural response in the human amygdala to fearful and happy facial expressions.Nature. 1996; 383: 812-815Crossref PubMed Scopus (1604) Google Scholar), but the tools available at the time were limited. This is likely one reason why the field at the outset emphasized animal studies, where invasive experimental approaches were already well established. Social neuroscience underwent a major transformation in the late 1990s with the advent of fMRI, which led to the emergence of "social cognitive neuroscience" (Ochsner and Lieberman, 2001Ochsner K.N. Lieberman M.D. The emergence of social cognitive neuroscience.Am. Psychol. 2001; 56: 717-734Crossref PubMed Scopus (377) Google Scholar), a subdiscipline that has now grown to constitute a large component of the field. The two main societies for social neuroscience, the Society for Social Neuroscience (S4SN) and the Social and Affective Neuroscience Society (SANS), emphasize these dual origins, respectively. However, the field is still very much in its infancy: SANS was established in 2008, S4SN was only established in 2010 (each has about 300 members), and a European society is just emerging (ESAN). These societies are comparable in size to organizations such as the Society for Neuroeconomics (which is slightly older and larger) but are far smaller than the Cognitive Neuroscience Society (founded in 1994; membership > 2,000) or the Society for Neuroscience (founded in 1969; membership > 40,000). The two flagship journals of social neuroscience, Social Cognitive and Affective Neuroscience ("SCAN," publisher: Oxford Press) and Social Neuroscience (publisher: Taylor and Francis), predate the societies only slightly (both were founded in 2006). SANS and S4SN each have about one-third international members, including growing constituencies in South America and Asia (two venues for S4SN's annual meetings) and a strong student representation, reflecting a young, vibrant, and rapidly growing community. Currently amounting to just over 3%, extrapolation suggests that by the early 2020s, social neuroscience publications could constitute 10% of all neuroscience publications (Figure 1A). Many programmatic questions are currently debated in the field. How important is it to relate social behavior to microscopic neurobiological and genetic levels? How important is it to study animal species other than humans? How important is translational work in comparison to basic research? To get an initial overview of how people think about some of these questions, we asked a sample of social neuroscientists to weigh in. Their answers illustrate the broad base that constitutes social neuroscience, the acknowledgment of intense interdisciplinary effort, and the sense of an open landscape in the years ahead (see Figures 1B and 1C; Table 3). Although social neuroscience needs to be broad, it also needs a focus for nucleation, otherwise it threatens simply to merge with cognitive neuroscience or splinter into an array of otherwise unrelated projects. And of course, there is a focus: it is the word "social" that is raising questions about how best to circumscribe this term. In studying the "social," social neuroscience is about the neurobiology involved in perceiving, thinking about, and behaving toward other people. But it also encompasses conspecific interactions between nonhuman animals, the anthropomorphization of stimuli that are not really social at all, and thinking about oneself. The underlying presumption is that these are all intimately related: animals evolved neural mechanisms for interacting with one another and with other species commonly encountered. Conspecifics, predators, and prey thus all require particular repertoires of behavioral interactions, made possible by particular suites of cognitive and neurobiological processes. In humans, these can be applied very widely and flexibly, including cases of anthropomorphization and thinking about ourselves. In addition, they extend beyond typical dyadic interactions to both the larger-scale collective interactions of groups and the indirect and symbolic interactions of individuals through the internet, all hot topics for future study, as we note further below. If all these diverse forms of social behavior were to recruit overlapping processes and activate overlapping brain regions in neuroimaging studies, we would gain confidence that they are sufficiently cohesive to substantiate the field of social neuroscience. Indeed, this is the strong picture that is emerging so far. All of the features and challenges noted above also make social neuroscience an incredibly exciting field, and one highly attractive to young scientists. There is a plethora of open questions (Tables 2 and 3), a wide range of parent disciplines from which the field can be approached (Figure 1B), and a strong sense of ongoing and impending progress. Whereas previous generations of social neuroscientists were trained in different fields, we are now coming into our first batch of constituents reared in this multidisciplinary environment; whereas several hurdles and critiques were tackled in the recent past, the field has now synthesized initial views of the "social brain" (Figure 2) and generated powerful new approaches to mining and modeling data (Table 1). Next, we briefly take stock of the major current themes, before extrapolating into the future.Table 1Three Approaches to Identifying Core Social ProcessesApproachExamplesProsCons(A) Social psychology theories(1) mentalizing processes (simulation versus theory of mind)(2) self-relevant versus other-directed(3) automatic versus controlled processes (reflexive versus reflective)(1) ontology of processes that map on to social psychology(2) often intuitive, can translate to "folk psychology"(3) rich theoretical frameworks already exist(1) may not map well to neurobiology(2) can become entrenched and hard to modify(3) Sometimes not strongly justified by data(B) Data-driven ontology(1) reverse-correlation techniques(2) meta-analyses (e.g., ALE)(3) NeuroSynth mining(1) relatively unbiased and objective(2) data-driven; can derive novel concepts(3) typically based on very large data sets; reliable(1) some aspects very new; still computationally expensive(2) no agreed-upon approach; hidden biases possible(3) interpretation of discovered processes is problematic(C) Computational models(1) neuroeconomics(2) vision(3) motor control(1) can cut across levels of analysis(2) quantitative and parametric(3) data drive and constrain model selection(1) constraining model selection nontrivial(2) formalizing social phenomena is difficult(3) can quickly become overly complicatedWe outline three very different approaches that each have strengths and weaknesses, together with a few well-known examples from each. All three are currently in use, although (B) and (C) are much more recent than (A). Our own prescription would be to make use of all three and vet them against one another, something almost never undertaken currently but eminently possible. For instance, (A) and (B) could be used to generate models under (C); the results from this could be used to refine (A). Or, (B) could be used to check results from (A) and/or (C) against the large corpus of studies in the literature. We do not believe that we can completely dispense with any of the three, as (A) is essential in giving us theoretical frameworks rich and intuitive enough to let us understand social cognition; (B) is essential in linking our concepts to cumulative data; and (C) is essential in embedding the concepts in the brain's computations and likely best at translating across different levels. Open table in a new tab We outline three very different approaches that each have strengths and weaknesses, together with a few well-known examples from each. All three are currently in use, although (B) and (C) are much more recent than (A). Our own prescription would be to make use of all three and vet them against one another, something almost never undertaken currently but eminently possible. For instance, (A) and (B) could be used to generate models under (C); the results from this could be used to refine (A). Or, (B) could be used to check results from (A) and/or (C) against the large corpus of studies in the literature. We do not believe that we can completely dispense with any of the three, as (A) is essential in giving us theoretical frameworks rich and intuitive enough to let us understand social cognition; (B) is essential in linking our concepts to cumulative data; and (C) is essential in embedding the concepts in the brain's computations and likely best at translating across different levels. Social neuroscience has made major contributions in many respects. One methodological accomplishment has been to help develop and refine fMRI methods, an advance linked in part to prior critiques we note below. A topical contribution has been the study of individual differences in social behavior. This topic is now often related to genotypic differences (Green et al., 2008Green A.E. Munafò M.R. DeYoung C.G. Fossella J.A. Fan J. Gray J.R. Using genetic data in cognitive neuroscience: from growing pains to genuine insights.Nat. Rev. Neurosci. 2008; 9: 710-720Crossref PubMed Scopus (184) Google Scholar) and even to structural brain differences (Kanai and Rees, 2011Kanai R. Rees G. The structural basis of inter-individual differences in human behaviour and cognition.Nat. Rev. Neurosci. 2011; 12: 231-242Crossref PubMed Scopus (689) Google Scholar), with investigation of the effects of culture a hot topic (Rule et al., 2013Rule N.O. Freeman J.B. Ambady N. Culture in social neuroscience: a review.Soc. Neurosci. 2013; 8: 3-10Crossref PubMed Scopus (34) Google Scholar). There have been major extensions also to understanding psychiatric illness (Cacioppo et al., 2007Cacioppo J.T. Amaral D.G. Blanchard J.J. Cameron J.L. Carter C.S. Crews D. Fiske S. Heatherton T. Johnson M.K. Kozak M.J. et al.Social neuroscience: progress and implications for mental health.Perspect. Psychol. Sci. 2007; 2: 99-123Crossref Scopus (85) Google Scholar), as well as the effects of stress and immune function on mood in healthy people (Eisenberger and Cole, 2012Eisenberger N.I. Cole S.W. Social neuroscience and health: neurophysiological mechanisms linking social ties with physical health.Nat. Neurosci. 2012; 15: 669-674Crossref PubMed Scopus (311) Google Scholar). And there has been a recent flurry of attention to real social interactions (as opposed to mere simulations of them), an aspect that has almost spawned its own subdiscipline and is of interest to cognitive scientists more broadly (Schilbach et al., 2013Schilbach L. Timmermans B. Reddy V. Costall A. Bente G. Schlicht T. Vogeley K. Toward a second-person neuroscience.Behav. Brain Sci. 2013; 36: 393-414Crossref PubMed Scopus (882) Google Scholar). A good example of one of the earliest success stories in social neuroscience began in the late 1980s and early 1990s with the discovery of the roles of the neuropeptides oxytocin (OT) and arginine vasopressin (AVP) in social affiliative behaviors. Not only did this work result in a string of elegant papers dissecting the neural circuits and genetic polymorphisms governing affiliative behavior in an animal model (voles; Insel and Young, 2001Insel T.R. Young L.J. The neurobiology of attachment.Nat. Rev. Neurosci. 2001; 2: 129-136Crossref PubMed Scopus (862) Google Scholar), but it was also extended to behavioral and neuroimaging studies in humans, including extensions to treatments of psychiatric disorders (Baumgartner et al., 2008Baumgartner T. Heinrichs M. Vonlanthen A. Fischbacher U. Fehr E. Oxytocin shapes the neural circuitry of trust and trust adaptation in humans.Neuron. 2008; 58: 639-650Abstract Full Text Full Text PDF PubMed Scopus (862) Google Scholar, Insel and Young, 2001Insel T.R. Young L.J. The neurobiology of attachment.Nat. Rev. Neurosci. 2001; 2: 129-136Crossref PubMed Scopus (862) Google Scholar, Kosfeld et al., 2005Kosfeld M. Heinrichs M. Zak P.J. Fischbacher U. Fehr E. Oxytocin increases trust in humans.Nature. 2005; 435: 673-676Crossref PubMed Scopus (2502) Google Scholar, McCall and Singer, 2012McCall C. Singer T. The animal and human neuroendocrinology of social cognition, motivation and behavior.Nat. Neurosci. 2012; 15: 681-688Crossref PubMed Scopus (190) Google Scholar). Previously known to play a role in bodily processes related to mammalian child-rearing (OT) and kidney function (AVP), it is now well established that both OT and AVP influence a broad range of social behaviors. In nonhuman mammals, OT has been shown to underlie social bonding behaviors, AVP has been linked to long-term pair bonding and male aggression, and the brain regions in which receptors for these peptides are found have been drawn into a circuit for processing social signals that mediate these behaviors. More than that, genetic polymorphisms in the receptor genes have been linked to species differences in social behavior, providing a story that cuts powerfully across widely different levels of analysis (Insel and Fernald, 2004Insel T.R. Fernald R.D. How the brain processes social information: searching for the social brain.Annu. Rev. Neurosci. 2004; 27: 697-722Crossref PubMed Scopus (410) Google Scholar, Insel and Young, 2001Insel T.R. Young L.J. The neurobiology of attachment.Nat. Rev. Neurosci. 2001; 2: 129-136Crossref PubMed Scopus (862) Google Scholar). In the past decade, researchers have begun to explore the influence of OT (which can be delivered intranasally) and, to a lesser extent, AVP on human social behavior: OT can increase social trust (Kosfeld et al., 2005Kosfeld M. Heinrichs M. Zak P.J. Fischbacher U. Fehr E. Oxytocin increases trust in humans.Nature. 2005; 435: 673-676Crossref PubMed Scopus (2502) Google Scholar), normal variation in the receptor distribution for OT and AVP in the human population has been linked to measures of altruism and empathy, and OT administration has even been proposed as one component for treating autism (Yamasue et al., 2012Yamasue H. Yee J.R. Hurlemann R. Rilling J.K. Chen F.S. Meyer-Lindenberg A. Tost H. Integrative approaches utilizing oxytocin to enhance prosocial behavior: from animal and human social behavior to autistic social dysfunction.J. Neurosci. 2012; 32: 14109-14117Crossref PubMed Scopus (108) Google Scholar). Although it has also become clear that the effect of OT on social behavior is highly dependent on individual differences and context, the topic remains a rich future area of study linking pharmacological, ecological, and psychiatric approaches. Another major achievement of social neuroscience has been the linking of social and physical health (Eisenberger and Cole, 2012Eisenberger N.I. Cole S.W. Social neuroscience and health: neurophysiological mechanisms linking social ties with physical health.Nat. Neurosci. 2012; 15: 669-674Crossref PubMed Scopus (311) Google Scholar, Eisenberger, 2012Eisenberger N.I. The pain of social disconnection: examining the shared neural underpinnings of physical and social pain.Nat. Rev. Neurosci. 2012; 13: 421-434Crossref PubMed Scopus (89) Google Scholar). Early work identifying the neural correlates of social pain (e.g., from exclusion or rejection by others) found a remarkable overlap with systems involved in physical pain and linked individual differences in physical and social pain sensitivity. Perhaps even more telling was that experiences that increased social pain also strongly influenced physical pain, and vice versa (Eisenberger, 2012Eisenberger N.I. The pain of social disconnection: examining the shared neural underpinnings of physical and social pain.Nat. Rev. Neurosci. 2012; 13: 421-434Crossref PubMed Scopus (89) Google Scholar). On the flip side, social support has been shown to reduce both subjective reports and neural responses related to physical pain, while taking Tylenol reduces not only physical pain but also hurt feelings and neural responses to social exclusion (Dewall et al., 2010Dewall C.N. Macdonald G. Webster G.D. Masten C.L. Baumeister R.F. Powell C. Combs D. Schurtz D.R. Stillman T.F. Tice D.M. Eisenberger N.I. Acetaminophen reduces social pain: behavioral and neural evidence.Psychol. Sci. 2010; 21: 931-937Crossref PubMed Scopus (324) Google Scholar). Far from simply justifying the shared (though often underappreciated) sense that social pain is as real as physical pain, the establishment of this link between the two has opened up a broad range of new studies, emphasizing the highly interactive nature of social cognition and behavior (a topic to which we will return below). Perhaps in part as a consequence of the inherent attraction of the questions investigated by social neuroscience, the field has received considerable attention from the media and hence also the general public. This has not always been a good thing. Some overpromotion of early findings in the field resulted in a subsequent backlash against social neuroscience for its failure to deliver on those earlier promises. Particularly acute was a recent episode highlighting the difficulty of supporting many claims drawn from statistical analyses of neuroimaging data (Vul et al., 2009Vul E. Harris C. Winkielman P. Pashler H. Puzzlingly high correlations in fMRI studies of emotion, personality, and social cognition.Perspect. Psychol. Sci. 2009; 4: 274-290Crossref PubMed Scopus (1048) Google Scholar), an issue that pertains to both cognitive neuroscience and social psychology more broadly, but that came to a head at the intersection of these two fields. Social neuroscience, as well as the neuroimaging and psychology fields in general, has been considerably sensitized to these issues, with the overall result that statistical inferences are applied more cautiously by authors and better scrutinized by journal reviewers, publication biases are being exposed in the literature, and increased value has been assigned to replication (Francis, 2012Francis G. Publication bias and the failure of replication in experimental psychology.Psychon. Bull. Rev. 2012; 19: 975-991Crossref PubMed Scopus (129) Google Scholar, Green et al., 2008Green A.E. Munafò M.R. DeYoung C.G. Fossella J.A. Fan J. Gray J.R. Using genetic data in cognitive neuroscience: from growing pains to genuine insights.Nat. Rev. Neurosci. 2008; 9: 710-720Crossref PubMed Scopus (184) Google Scholar, Kriegeskorte et al., 2010Kriegeskorte N. Lindquist M.A. Nichols T.E. Poldrack R.A. Vul E. Everything you never wanted to know about circular analysis, but were afraid to ask.J. Cereb. Blood Flow Metab. 2010; 30: 1551-1557Crossref PubMed Scopus (159) Google Scholar, Poldrack, 2011Poldrack R.A. Inferring mental states from neuroimaging data: from reverse inference to large-scale decoding.Neuron. 2011; 72: 692-697Abstract Full Text Full Text PDF PubMed Scopus (444) Google Scholar). However, given the complexity of the phenomena studied by social neuroscience, these issues will continue to demand attention. Their exposure is shaping collective efforts to control for false-positive findings and to construct large databases against which new results can be compared and interpreted (Poldrack, 2011Poldrack R.A. Inferring mental states from neuroimaging data: from reverse inference to large-scale decoding.Neuron. 2011; 72: 692-697Abstract Full Text Full Text PDF PubMed Scopus (444) Google Scholar, Yarkoni et al., 2011Yarkoni T. Poldrack R.A. Nichols T.E. Van Essen D.C. Wager T.D. Large-scale automated synthesis of human functional neuroimaging data.Nat. Methods. 2011; 8: 665-670Crossref PubMed Scopus (1916) Google Scholar). With social neuroscience now inoculated with the above critiques, the field is ready to tackle a number of current "hot topics" that we mention only briefly here for the sake of space. The processes that come into play during real social interactions have been dubbed the "dark matter" of social neuroscience (Schilbach et al., 2013Schilbach L. Timmermans B. Reddy V. Costall A. Bente G. Schlicht T. Vogeley K. Toward a second-person neuroscience.Behav. Brain Sci. 2013; 36: 393-414Crossref PubMed Scopus (882) Google Scholar). Studying ecologically valid social interactions in humans is often difficult for two simple reasons: it is ethically tricky (in many cases requiring deception because people otherwise know they are part of an experiment), and it relinquishes some degree of experimental control. It is also an unusually rich and interesting topic, exactly what social psychologists would wish to study and many neurobiologists think is too fuzzy to study. One prescription for the future might be to draw on both of these fields and to study real social interactions—but in well-controlled animal models. Animals usually do not know they are part of an experiment, and achieving ecological validity has a long track record in neuroethology. On the other hand, studies in nonhuman animals have their own problems, including lack of verbal report and explicit instruction, making it often very difficult to know how to interpret what we observe (Figure 3). This topic should in our view be considered simply one aspect of studying individual differences, including cultural effects. The extent to which any given social behavior is pathological or not is often relative to a particular society and is almost always on a spectrum. The recent push by the National Institute of Mental Health to discover more basic dimensions along which psychiatric illnesses can be described (Kapur et al., 2012Kapur S. Phillips A.G. Insel T.R. Why has it taken so long for biological psychiatry to develop clinical tests and what to do about it?.Mol. Psychiatry. 2012; 17: 1174-1179Crossref PubMed Scopus (698) Google Scholar), as opposed to the categorical classifications provided by DSM-based diagnoses, also opens up this topic to fusion with data-driven approaches (Poldrack et al., 2012Poldrack R.A. Mumford J.A. Schonberg T. Kalar D. Barman B. Yarkoni T. Discovering relations between mind, brain, and mental disorders using topic mapping.PLoS Comput. Biol. 2012; 8: e1002707Crossref PubMed Scopus (84) Google Scholar). The field is especially exciting because, perhaps for the first time, we can begin to see a strong alternative to the symptom-driven classification of mental disorders provided by traditional psychiatry. Just as psychiatry has embraced approaches from molecular biology and cognitive neuroscience, it should embrace computational tools and modeling methods. If we want to be able to map disorders onto the brain, we need models that specify particular cognitive processes so that we can understand which ones are explanatory and how. Computational psychiatry, in our view, will be a major focus within social neuroscience in the near future (Montague et al., 2012Montague P.R. Dolan R.J. Friston K.J. Dayan P. Computational psychiatry.Trends Cogn. Sci. 2012; 16: 72-80Abstract Full Text Full Text PDF PubMed Scopus (457) Google Scholar). Over the past 25 years, the type and quality of our social interactions have undergone a profound shift as online interactions (e.g., email, instant messaging, social networks) have supplemented, and in many cases supplanted, face-to-face interactions. Indeed, one open question is how social development will be influenced by this radical shift in how we interact (e.g., without social cues that we have evolved to process). There are now several intriguing studies of the relationship between neural function and social networks (e.g., Bickart et al., 2011Bickart K.C. Wright C.I. Daut