The Cognitive Basis of Social Interaction Across the Lifespan
Edited by HEATHER J. FERGUSON Professor in Psychology, University
of Kent, UK
ELISABETH E. F. BRADFORD Lecturer
in Psychology, University of Dundee, UK
3
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Acknowledgements
This book was prepared with the support of a European Research Council grant to Heather Ferguson (Ref: CogSoCoAGE; 636458). This grant supported Elisabeth Bradford, Victoria Brunsdon, and Martina de Lillo, the authors of Chapters 6 and 9. For chapter 2, Tobias Schuwerk and Hannes Rakoczy were supported by a grant from the German Research Foundation (RA 2155/7-1 and SCHU 3060/1-1). For Chapter 8, Muireann Irish was supported by an Australian Research Council Future Fellowship (FT160100096), and Siddharth Ramanan by a University of Sydney, Faculty of Science Ph.D. Research Scholarship.
Thanks are due to Camilla Woodrow-Hill for help with proofreading and formatting draft chapters, and to Netanel Weinstein for providing comments on earlier versions of Chapter 4.
Contributors ix
Authors’ Biographies xi
1. The Cognitive Basis of Social Interaction Across the Lifespan: An Introduction 1
Heather J. Ferguson
2. Social Interaction in Infancy 27
Tobias Schuwerk and Hannes Rakoczy
3. Social Interaction in Early and Middle Childhood: The Role of Theory of Mind 47
Serena Lecce and Rory T. Devine
4. Development of Social Cognition in Adolescence and the Importance of Mating 70
Sarah Donaldson and Kathryn Mills
5. Mindreading in Adults: Cognitive Basis, Motivation, and Individual Differences 96
Ian A. Apperly and J. Jessica Wang
6. Social Interactions in Old Age 117
Victoria E. A. Brunsdon, Elisabeth E. F. Bradford, and Heather J. Ferguson
7. Understanding Atypical Social Behaviour Using Social Cognitive Theory: Lessons from Autism 147
Lucy A. Livingston and Francesca Happé
8. The Ageing Brain in Context: Towards a Refined Understanding of Social Cognition in Ageing and Dementia 177 Muireann Irish and Siddharth Ramanan
9. The Future of Research on Social Interaction 201
Elisabeth E. F. Bradford, Martina De Lillo, and Heather J. Ferguson
Contributors
Ian A. Apperly, Professor of Cognition and Development, School of Psychology, University of Birwmingham, UK
Elisabeth E. F. Bradford, Lecturer in Psychology, School of Social Sciences, University of Dundee, UK
Victoria E. A. Brunsdon, Postdoctoral Research Associate, School of Psychology, University of Kent, UK
Martina De Lillo, Doctoral Student, School of Psychology, University of Kent, UK
Rory T. Devine, Lecturer in Developmental Psychology, School of Psychology, University of Birmingham, UK
Sarah Donaldson, Doctoral Student, Department of Psychology, University of Oregon, USA
Heather J. Ferguson, Professor in Psychology, School of Psychology, University of Kent, UK
Francesca Happé, Professor of Cognitive Neuroscience, Institute of Psychiatry, Psychology & Neuroscience, King’s College London, UK
Muireann Irish, Professor of Cognitive Neuroscience, School of Psychology, Brain and Mind Centre, University of Sydney, Australia
Serena Lecce, Associate Professor in Developmental and Educational Psychology, Department of Brain and Behavioral Science, University of Pavia, Italy
Lucy A. Livingston, Lecturer in Psychology, School of Psychology, Cardiff University, UK
Kathryn Mills, Assistant Professor, Department of Psychology, University of Oregon, USA
Hannes Rakoczy, Developmental Psychologist, Department of Developmental Psychology, University of Göttingen, Germany
Siddharth Ramanan, Postdoctoral Research Associate, MRC Cognition and Brain Sciences Unit, University of Cambridge, UK
Tobias Schuwerk, Clinical and Developmental Psychologist, Department of Developmental and Educational Psychology, Ludwig-Maximilians-University of Munich, Germany
J. Jessica Wang, Lecturer in Psychology, Department of Psychology, Lancaster University, UK
Authors’ Biographies
Ian A. Apperly
Ian Apperly is a Professor of Cognition and Development in the School of Psychology at the University of Birmingham. He studied natural sciences at Cambridge University and completed his PhD at the University of Birmingham. His main research interest is in ‘mindreading’—the ability to take other people’s perspectives for communication, cooperation, competition, or deception—and he has built a strong international profile in this area. His work has been supported by funders including the Economic and Social Research Council, Medical Research Council, and Leverhulme Trust, and he authored a book, Mindreaders: The Cognitive Basis of Theory of Mind, in 2010. He has received prizes from the British Psychological Society and the Experimental Psychology Society.
Elisabeth E. F. Bradford
Elisabeth Bradford is a Lecturer in Cognitive and Developmental Psychology at the School of Social Sciences, University of Dundee (Scotland, UK). She completed her PhD at the University of St Andrews in 2016. Prior to her lectureship at the University of Dundee, Lizzie worked as a Postdoctoral Research Associate at the University of Kent (England, UK). Her research focuses on social cognition abilities, examining how these capacities change and develop across the lifespan, the impacts of deficits in social cognition abilities, how social cognition may vary across cultures, and the factors that may underlie successful engagement of social cognition abilities at different ages (e.g. executive functions).
Victoria E. A. Brunsdon
Victoria Brunsdon completed her undergraduate degree in Psychology and MSc in Experimental Psychology at the University of Birmingham, before completing a PhD in Cognitive Psychology at King’s College London. Following this, Victoria joined the University of Kent as a Postdoctoral Research Associate, working on the ‘CogSoCoAGE’ project examining the cognitive basis of social interactions across the lifespan. Her research combines cognitive-experimental measures, twin-model fitting, and structural equation modelling to study typical and atypical development.
Martina De Lillo
Martina De Lillo is a doctoral student in the School of Psychology at the University of Kent, where she has been funded by Heather Ferguson’s European Research Council grant (for the ‘CogSoCoAGE’ project) since 2016. Her research explores social and cognitive abilities across the lifespan, and tests whether social skills can be enhanced indirectly through executive function training.
Rory T. Devine
Dr Rory T. Devine is a Lecturer in Developmental Psychology at the University of Birmingham (UK). Dr Devine completed his PhD. at the University of Cambridge in 2013. Prior to taking up his Lectureship at the University of Birmingham, he worked as a Post-Doctoral Research Associate at the Centre for Family Research at the University of Cambridge and held the post of Director of Studies in Psychology and College Research Associate at Clare College, Cambridge. Dr Devine’s research uses cutting-edge statistical techniques and longitudinal methods to shed light on the social influences and social outcomes of individual differences in Theory of Mind and executive function in children.
Sarah Donaldson
Sarah Donaldson is a doctoral student in the Department of Psychology at the University of Oregon. She completed her Master’s Degree at Oakland University in 2016. Her research examines biological, cognitive, and behavioural underpinnings of romantic relationships during adolescence from an evolutionary perspective.
Heather J. Ferguson
Heather Ferguson is a Professor in Psychology at the University of Kent. She completed her PhD in Cognitive Neuroscience and Psycholinguistics at the University of Glasgow in 2007, followed by a twoyear postdoctoral research position at University College London. Her research broadly examines the cognitive basis of social communication. She examines the time-course of integration, the underlying neural mechanisms, and the extent to which constraints from world knowledge and context compete to influence social interaction and pragmatic language comprehension. This work has received generous funding, including a European Research Council grant examining social communication across the lifespan, and Leverhulme Trust grants that link social processing directly to language (including in autism spectrum disorders). Professor Ferguson has been formally recognized through multiple prize awards (e.g. the Psychonomic Early Career Award 2019), and holds key leadership positions in the discipline (e.g. Honorary Secretary to the Experimental Psychology Society).
Francesca Happé
Francesca Happé is Professor of Cognitive Neuroscience at the Institute of Psychiatry, Psychology & Neuroscience, King’s College London. Her research focuses on autism. She has explored social cognition and ‘mentalizing’ difficulties. She is also actively engaged in studies of abilities and assets in autism, and their relation to detail-focused cognitive style. Some of her recent work focuses on mental health on the autism spectrum, and underresearched groups including women and older people on the autism spectrum. She is a Fellow of the British Academy and the Academy of Medical Sciences, a past-President of the International Society for Autism Research, and has received the British Psychological Society (BPS) Spearman Medal and President’s Award, Experimental Psychology Society Prize, Royal Society Rosalind Franklin Award and a CBE for services to the study of autism. She is co-author/editor of two recent books—Autism: A New Introduction to Psychological Theory and Debate (with Sue Fletcher-Watson), and Girls and Autism: Educational, Family and Personal Perspectives (with Barry Carpenter and Jo Egerton).
Muireann Irish
Muireann Irish is an Australian Research Council Future Fellow and Professor of Cognitive Neuroscience at the Brain and Mind Centre, University of Sydney, where she leads the ‘Memory and Imagination in Neurological Disorders’ (MIND) group. As a cognitive neuroscientist, Muireann’s research focuses on the brain mechanisms underpinning complex expressions of memory, and how these processes are compromised in neurodegenerative disorders such as Alzheimer’s disease and frontotemporal dementia. To date, Muireann has produced more than a hundred publications exploring such capacities as autobiographical memory, future thinking, Theory of Mind, and daydreaming in dementia. The quality of Muireann’s
work has resulted in a series of prestigious awards including the 2019 Cognitive Neuroscience Society Young Investigator Award and the 2020 Gottschalk Medal from the Australian Academy of Science.
Serena Lecce
Dr Serena Lecce is an Associate Professor in Developmental and Educational Psychology at the Department of Brain and Behavioral Sciences, University of Pavia (Italy). She arrived at the University of Pavia as a doctoral student in 2001 and received a doctoral degree in 2004. Dr Lecce was appointed as a Lecturer in 2008 and was subsequently promoted to Associate Professor in 2014. She directs the Laboratory of Social Cognition where she conducts investigations of social and emotional functioning, and works closely with practitioners and teachers. Her research explores social and cognitive development across the lifespan. She is particularly interested in examining origins and consequences of individual differences of Theory of Mind for children’s social relationships and adjustment to school. A core applied focus of her research is the development and evaluation of training programmes to promote Theory of Mind and support social and emotional competence.
Lucy Anne Livingston
Lucy Anne Livingston is a Lecturer in Psychology at Cardiff University, based within the Centre for Human Developmental Science. She completed her BSc in Psychology at Durham University, followed by a Medical Research Council funded 1+3 MSc + PhD at the Institute of Psychiatry, Psychology and Neuroscience, King’s College London. Her PhD investigated heterogeneity in social cognition in autism through the study of compensatory mechanisms, with a particular focus on Theory of Mind. Lucy was awarded the 2020 British Psychological Society Developmental Section Neil O’Connor Award. She is also a visiting researcher at the UK
National Autistic Society and member of Autistica’s Physical Health and Ageing in Autism Study Group. Her current research interests include developmental trajectories and diverse outcomes in autism and other neurodevelopmental conditions, as well as a/typical social cognition across the lifespan.
Kathryn Mills
Dr. Kate Mills is an Assistant Professor in the Department of Psychology at the University of Oregon. She completed her doctoral studies at the Institute of Cognitive Neuroscience at University College London in 2015. Her programme of research applies longitudinal research methods to investigate the intertwined social, biological, and cognitive processes that underlie the development of skills needed to navigate the social environment.
Hannes Rakoczy
Hannes Rakoczy is a Developmental Psychologist at the University of Göttingen in Germany. His research focuses on early cognitive development in human ontogeny, with a complementary comparative perspective: which cognitive capacities are evolutionarily more ancient and develop early in human ontogeny in ways parallel to other primates? And which capacities are uniquely human, develop in more protracted ways, and potentially depend on language and culture?
Siddharth Ramanan
Siddharth Ramanan is a postdoctoral Research Associate at the MRC Cognition and Brain Sciences Unit, The University of Cambridge, UK. Siddharth completed his PhD in Psychology in 2020 at The University of Sydney, Australia, exploring inferior parietal lobe contributions to episodic memory in rare neurodegenerative syndromes. Siddharth’s research interests focus on understanding the mechanisms of heterogeneous cognitive and behavioural
symptoms in neurodegenerative dementia syndromes. As an early career researcher, Siddharth has received numerous competitive awards in recognition of his work including the 2014 Neuropsychology International Fellowship, 2018 BrightFocus Foundation Travel Award, and 2019 Margaret Ethel Jew Award for Dementia Research.
Tobias Schuwerk
Tobias Schuwerk is a Clinical and Developmental Psychologist at Ludwig-Maximilians-University of Munich, Germany. He studies Theory of Mind in children and adults with and without autism. He is particularly interested in its (neuro-)cognitive basis and its development during early childhood. Further, he investigates if–and, if so, how– the cognitive processes underlying Theory of Mind work differently in people with autism. An additional research focus addresses the question of how we use Theory of Mind in our everyday lives.
J. Jessica Wang
Jessica Wang is currently a Lecturer in Psychology at Lancaster University. She previously held a lectureship at Keele University, and research fellowships at the University of Birmingham and Université Catholique de Louvain in Belgium. She completed her PhD and MRes at the University of Birmingham, after graduating with a BSc in Psychology from the National Chung Cheng University in Taiwan. Jessica’s primary research interest is in Theory of Mind and communication. She investigates the cognitive, developmental lifespan, social, and cultural factors implicated in the way in which we think about others’ perspectives in various contexts. She is also interested in the spontaneous computation of low-level social information, such as eye gaze and visual perspectives.
1
The Cognitive Basis of Social Interaction Across the Lifespan
An Introduction
Heather J. Ferguson
1.1 Introduction
Social interactions form a hugely important aspect of everyday life, and their success (or lack of) has a heavy impact on our well-being. There is a common agreement that social cognition helps us to understand ourselves, others, and our environment through implicit and explicit processes (Moskowitz & Olcaysoy Okten, 2017), and that any cognitive process can reflect social ability if it involves a social agent or interaction. A vital part of successful social interaction is the ability to understand and predict events in terms of other people’s mental states, such as their intentions, beliefs, emotions, and desires (termed Theory of Mind [ToM]). In a single day, we might need to infer mental states for a range of individuals (e.g. a long-term partner versus a stranger), under various circumstances (e.g. watching a movie versus interacting with people), and given differing levels of importance (e.g. believing a friend left your tea in the kitchen rather than the lounge versus believing that the white powder a friend put in your tea was sugar rather than poison). Social cognition underlies nearly all aspects of successful interpersonal relations, because people need to keep track of other people’s knowledge, beliefs, and desires to understand their actions and intended meaning. Indeed, when we misunderstand another person’s meaning or intentions during conversation, this often leads to negative social implications, such as taking offence or restricting further social interactions. This book will focus on the cognitive mechanisms that underlie human social interaction, how these abilities change across the lifespan, from infancy to older age, and in healthy and atypical development/ageing.
To date, research studies of different stages of the lifespan have progressed largely in isolation from each other, with the majority tending to focus on a single, static age group, and with very little cross-talk between developmental stages. This book therefore aims to bring together these diverse pockets of research, presenting a unique, comprehensive picture of the developmental trajectory, and decline, of social interaction capacities, and enabling a unified dynamic exploration of the
cognitive basis of social interaction across the lifespan. Over nine chapters, leading researchers in this field provide an overview of the most recent research in this area, contribute to key debates on social phenomena (including their underlying mechanisms, environmental triggers, and neural bases), and outline some innovative avenues for future research. In this introductory chapter, I will start by defining the concepts underlying social interaction and highlighting the importance of a lifespan approach. Then, I will outline some key theories and mechanisms that have been proposed to underlie communicative success, and showcase a range of methodological approaches to this topic, emphasizing the challenges in applying these methods across the lifespan.
1.2 Concepts underlying social interaction
Despite the importance of social interaction and the decades of research that have explored ToM, there remains no consensus on the taxonomy or mechanisms that underlie these abilities. Some researchers have recently begun to examine the factor structure of social cognition, revealing a great deal of variance in the number of components involved, and a lack of consensus on the interdependence between them. For example, Fiske and Taylor (2013) identified 14 domains of social cognition, including more basic abilities such as social memory and social attention, and more complex concepts like social inferences and decision making. Happé and Frith (2014) tested this question using data on atypical social cognition, and identified at least eight distinct components, including mental state attribution, empathy, self-processing, and affiliation. In their review, Happé et al. (2017), focused on several sociocognitive processes including imitation, biological motion, empathy, social learning, and ToM, and discussed the challenges involved in identifying the components of social cognition and understanding the ways in which they may be related (including a lack of agreed lexical terms for sociocognitive processes). More recently, Beaudoin and colleagues (2020) conducted a systematic review of 830 articles and proposed a new ‘Abilities in Theory of Mind Space’ (ATOMS) framework, which provides a taxonomy of seven mental state categories (emotions, desires, intentions, percepts, knowledge, beliefs, and mentalistic understanding of non-literal communication). For future research, it will be important to consider whether common representational mechanisms are involved when these social skills require a representation of the self versus other.
In addition to these questions about the specific components that make up social cognition, researchers have distinguished broad categories of social behaviour. For example, ToM has been divided into affective and cognitive facets, whereby affective ToM refers to the ability to mentalize another person’s emotions, while cognitive ToM requires comprehension of others’ beliefs or intentions (ShamayTsoory & Aharon-Peretz, 2007). ToM can therefore be seen as distinct from
compassion, as well as early implicit representations of mental states, such as joint attention and imitation, and more complex social abilities, such as cooperation or deception.
Finally, perspective-taking is considered as a means through which people can infer others’ mental states. It involves adopting someone else’s visual or spatial perspective and is typically examined along one of two dimensions: one that simply assesses what someone else can see (termed ‘Level 1’ perspective-taking), and another that assesses how that person sees something (termed ‘Level 2’ perspectivetaking). These two types of perspective-taking can be differentiated according to whether or not they require one to mentally rotate into the position of the other person (Michelon & Zacks, 2006; Surtees et al., 2013).
1.3 The importance of a lifespan approach
Until relatively recently, most researchers assumed that adults are fully capable ‘mindreaders’, having developed the necessary skills for even complex social interaction between the ages of two and seven years old (Wellman et al., 2001). In fact, over 50 years of research have focused on the developmental trajectory of ToM within this narrow age range, demonstrating a ‘transitional phase’ in ToM ability between ages three and five (e.g. Wimmer & Perner, 1983).
Over the past couple of decades, new paradigms and methodological advances have facilitated an exciting new body of research that has examined social communication in infancy and beyond childhood. This work has ignited debates about whether infants as young as six months old are capable of spontaneously representing and reasoning about the (false) beliefs of others (e.g. Kovács et al., 2010; Kulke & Rakoczy, 2018; Schuwerk et al., 2018; Southgate & Vernetti, 2014). Importantly, it has also demonstrated that social development continues through adolescence and well into our twenties (e.g. Blakemore, 2008; Dumontheil et al., 2010), that even healthy adults can experience difficulties considering another person’s point of view when that view conflicts with their own (e.g. Apperly et al., 2008; Birch & Bloom, 2007; Keysar et al., 2000), and that specific impairments in these abilities emerge with increasing age (e.g. Bailey & Henry, 2008; German & Hehman, 2006; Phillips et al., 2011). It is therefore likely that early studies overlooked key stages in the development of social interaction skills that extend beyond the childhood years.
Moreover, research has established the study of social communication in healthy adults as a research topic in its own right, showing a great deal of individual variation in performance (e.g. Bradford et al., 2015; Brown-Schmidt, 2009; Cane et al., 2017; Lin et al., 2010; Rubio-Fernández & Geurts, 2016; Brunyé et al., 2012; Ferguson et al., 2015a; Kessler & Wang, 2012; Nielsen et al., 2015; Converse et al., 2008; Wu & Keysar, 2007), and that even healthy adults might only consider
other people’s perspectives under specific task demands (Back & Apperly, 2010; Ferguson et al., 2015b). Examining effects in healthy adults is particularly valuable given recent evidence suggesting that some aspects of our social abilities reach their peak and begin to decline in the early thirties (Germine et al., 2011).
Comparatively less research has examined changes in social interaction in older age, though the majority of studies on this topic indicate that ToM abilities are subject to age-related decline (see Moran, 2013, for a review, and Henry et al., 2013, for a meta-analysis). Research has shown that age-related difficulties in ToM mediate a substantial decline in social participation in older adults, which can in turn lead to isolation, loneliness, and poor health (Bailey et al., 2008). Importantly, debate continues regarding the age at which these declines first appear (see Brunsdon et al., 2019; Pardini & Nichelli, 2009; Duval et al., 2011), with some researchers suggesting that social impairments first emerge in middle age and increase rapidly through older age (e.g. Bernstein et al., 2011). In addition, there is uncertainty regarding the task or domain-specificity of agerelated social impairments, with affective ToM appearing to be relatively spared in older adults (e.g. Bottiroli et al., 2016; Castelli et al., 2010; Henry et al., 2013; Mahy et al., 2014; Pardini & Nichelli, 2009), and subjective experience of ToM showing no effects of age (which suggests an age-related impairment in metacognition; Duval et al., 2011).
Finally, it is important to note that the typical trajectory of social development is disrupted in various neurodevelopmental and neurodegenerative disorders (e.g. autism and dementia). Research that has interrogated the patterns of behaviour, neural substrates, and co-occurrences in these disorders has provided valuable insights into the mechanisms and connections that exist in the typical development of social interaction.
1.4 Key theories and mechanisms underlying communicative success
Traditional theories of ToM have leaned heavily on philosophy of mind, defining an observers’ key task as reasoning about the relationship between an agent’s intentions, beliefs, and desires and their actions, either through a framework of concepts about the mind (‘theory theory’ or ‘folk psychology’, Churchland, 1991) or through a re-enactment of others’ minds in one’s own mind (‘simulation theory’, Davies & Stone, 1995a, b). These models are based on the idea that children learn about social behaviour by observing others interacting in the world or by reflecting on their own intentional behaviour and emotions, and use this experience to develop and revise theories about the connections and behaviours of people in their social world. However, these models focus on the early development of social
understanding, and therefore do not make any testable predictions about the developmental trajectory of social abilities beyond childhood, including how and why they might decline in older age.
Over the past decade or so, there has been increasing speculation about the mediating role of cognitive mechanisms in successful social interaction, with the majority of new psychological theories explicitly reflecting on this relationship when explaining social cognitive phenomena. These accounts therefore offer a more promising view on how social interaction might change across the lifespan, because much is known about how cognitive performance changes with age (Diamond, 2002), including the observation that some aspects of age-related cognitive decline begin when adults are in their twenties and thirties (Salthouse, 2009).
Among the first to detail a theoretical framework that links social abilities with cognitive mechanisms, and therefore offers a clear developmental path, is the ‘two systems model for mindreading’, proposed by Apperly and Butterfill (2009; see also Apperly, 2009). According to this account, two systems exist for belief reasoning: one is automatic, inflexible, and cognitively efficient (and hence reflects animals’ and infants’ basic ToM, and adults’ moment-by-moment social cognition), and the other is more flexible but is cognitively demanding (and therefore more suited for explicit and planned ToM inferences). This two systems model predicts that, while some aspects of ToM performance will correlate with changes in cognitive abilities (e.g. working memory, inhibitory control, belief reasoning, and inferences from language), those that tap into the cognitively efficient system (e.g. emotion reading and visual perspective-taking) should not reveal a comparable change with reduced cognitive abilities. Applied to lifespan development, this model proposes that basic social inferences that do not rely on cognitive abilities are spontaneously activated much earlier than four years old, the age at which children are known to pass explicit tests of false beliefs. The model also proposes that development of more sophisticated forms of social interaction continues through childhood and adolescence as children rely on increasingly complex cognitive mechanisms, which are known to develop over a protracted period into early adulthood (Best & Miller, 2010; De Luca et al., 2003). Finally, the model accounts for a decline in more cognitively demanding social abilities into older age, as age-related declines in cognitive functioning are relatively robust due to changes in the frontal lobes, specifically age-related volume reduction in the prefrontal cortex (GunningDixon & Raz, 2003). Moreover, there is a vast amount of heterogeneity in regards to when cognitive abilities peak and decline throughout the lifespan, which resonates with the high degree of individual variance seen in social abilities. While the importance of cognitive mechanisms to support some aspects of social interaction has been largely corroborated by empirical evidence, the need to have two separate systems to manage different social situations has been challenged by Carruthers (2016), who suggests that a single mindreading
system can account for the need to recruit cognitive resources during some mindreading tasks. Specifically, the one- system account proposes that a single system exists to support ToM. This system operates in a fairly rudimentary way in early infancy, based on a set of conceptual primitives and thoughtattributions. It becomes increasingly efficient from infancy to childhood through a continuous period of development, as social and communicative experience grows, cognitive and language mechanisms mature, and the connection between mindreading and cognition strengthens. Importantly, this model predicts that success in social interaction will vary depending on the demands placed on executive function and language, both of which are subject to agerelated decline.
A recent account has proposed that social interaction is a key mechanism though which ‘cognitive gadgets’ (including reasoning, using language, and mindreading) are culturally inherited and learned (Heyes, 2018). Specifically, Heyes argues that infants are born with a huge range of genetically programmed abilities and assumptions about the world (including instincts to attend to the social world around us, learn, and remember), and these skills and beliefs combined with exposure to culture-soaked environments during infancy and childhood prompt the development of a range of cognitive gadgets (e.g. mindreading, empathy, and imitation). According to the model, the nature of cognitive gadgets that are passed on between people will be influenced by the social context they grow up in. For example, changes in technology and family cultures will lead to subtle changes in the cognitive gadgets that children acquire, and if they are successful those new gadgets will be passed on. As such, this model predicts that social abilities change, not only over lifespan development, but will also vary over social and economic environments, and over different generations.
Finally, Conway et al. (2019) have proposed a model that aims to explain the significant variability with which individuals are able to make inferences about others’ minds, and the vastly different minds that we need to infer mental states for. Conway and colleagues adopt a ‘Mind-Space’ framework, in which other people’s minds are represented in a multidimensional space that varies on multiple axes (e.g. cognitive abilities, personality traits, and behavioural tendencies). People therefore learn to adapt their behaviour and social interaction style depending on their Mind-Space representation of the other person (e.g. their age or linguistic background; see Ferguson et al., 2018; Grey & Van Hell, 2017). Therefore, this model allows us to make some predictions about how children’s accumulating experience with their own and others’ minds leads to a better ability to represent Mind-Space and make appropriate inferences about others’ mental states. It also helps explain the variability in accuracy of mental state inferences in adulthood. However, it does not set any testable predictions for whether or how this ability might change in later life.
1.5 A special role for executive functions
As can be seen in the models described above, cognitive abilities, including executive functions (EFs), provide a key component of success in social interaction. EF is a commonly used ‘umbrella term’ to describe the processes that are responsible for higher-level action control (e.g. planning, inhibition, coordination, and control of behaviours), and are necessary to maintain specific goals and resist distraction from alternatives. Indeed, a long tradition of empirical research has demonstrated a robust relationship between the acquisition of EFs and improvements in ToM skills among young children, independent of age and IQ (e.g. Carlson et al., 2004; Perner & Lang, 1999). However, the exact direction of this relationship remains under debate, with some researchers claiming that ToM is needed for EF (Carruthers, 1996; Perner, 1998; Perner & Lang, 1999, 2000), and others arguing that ToM requires EF (Russell, 1996, 1997; Pacherie, 1997). The specific EF skills that have been shown to be strongly correlated with ToM development are working memory (Keenan et al., 1998), inhibitory control (i.e. ignoring irrelevant information; Carlson et al., 2004), and cognitive flexibility (i.e. switching between different tasks; Hughes, 1998). These links make sense given that successful social cognition requires one to hold in mind multiple perspectives (i.e. working memory), suppress irrelevant perspectives (i.e. inhibitory control), and switch between these two perspectives depending on context (i.e. cognitive flexibility).
Neuropsychological research has demonstrated a protracted period of EF development, which begins in early childhood (~2 years old) and continues into young adulthood, with each sub-component of EF developing at its own rate (Diamond, 2002). For example, working memory and planning develop throughout childhood and into adolescence or early adulthood (e.g. Bishop et al., 2001; Gathercole et al., 2004), whereas cognitive flexibility and inhibition are thought to reach adultlike levels by age 12 (e.g. Crone et al., 2006; Van den Wildenberg & Van der Molen, 2004). This neurocognitive development corresponds with children’s ability to pass increasingly complex tests of ToM, from implicit awareness of others’ perspectives around 18 months old (e.g. Buttelmann et al., 2009; Kovács et al., 2010; Onishi & Baillargeon, 2005; Senju et al., 2011), to first-order false belief tasks around 4 years old (Astington, 1993; Wellman & Bartsch, 1988), and second-order false belief tasks around 7 or 8 years old (Perner & Wimmer, 1985; Sullivan et al., 1994). Moreover, recent research has established that the social brain continues to develop throughout adolescence (Blakemore & Mills, 2014; Dumontheil, 2016), and that these structural changes underlie major developmental progressions in social cognition, which interact with improvements in cognitive control (Humphrey & Dumontheil, 2016; Mills et al., 2015).
Further evidence of the strong developmental relationship between ToM and EFs comes from research on neurodevelopmental disorders, most notably autism spectrum disorder (ASD). ASD is diagnosed behaviourally, based on
