This proposal will address the need to better understand the interplay between behavioural and biological mechanisms in human development. It will make substantial contributions to our theoretical understanding of social and cognitive development, social behaviour, and their impact on health and behaviour in childhood, adolescence and early adulthood, integrating recent developments in epigenetics. It will develop the empirical knowledge base in these areas, in order to support the development of novel interventions, and create an international hub linked to existing major research groupings.

Intrapersonal, interpersonal and environmental influences (such as family environment, early adversity, and socioeconomic position) at different stages of the life course are critical to the development of behaviour. These influences need to be understood in order to develop and optimise interventions to improve health and wellbeing. However, knowledge of the behavioural and psychological mechanisms of behavioural control, their development through infancy, adolescence and early adulthood, and their relationship with social behaviour, health and wellbeing, remain poorly integrated, and are rarely (if ever) investigated within a single data set. We propose a cohesive programme of research intended to provide a comprehensive understanding of the relationship between cognition, social behaviour, and impulsivity and risk taking. This will be allied to a life course perspective, to understand the role of social and environmental influences at every stage of development into early adulthood.

The Avon Longitudinal Study of Parents and Children (ALSPAC) forms the core resource on which this proposal is structured, utilising the wide range of phenotypic and environmental measures available, in addition to biological samples, genetic and epigenetic information and linkage to health and administrative records. This proposal is a collaborative project across the Universities of Bath, Bristol, Cardiff and Exeter, and will be supported by a wider network of national and international collaborators. It will be structured into three main workstreams, corresponding to our three main aims.

Aim 1: Understand the cognitive precursors (e.g., attentional and perceptual processes) of social behaviour, and health and wellbeing.

Aim 2: Understand the developmental pathways, trajectories and mechanisms associated with social behaviour (in particular sexual behaviour and aggressive behaviour).

Aim 3: Understand social, cognitive and environmental influences on impulsivity and high-risk behaviours, and subsequent health and wellbeing.

Workstream 1 (Social and Cognitive Development): This work will focus on the cognitive precursors of social behaviour, and health and wellbeing. There is growing interest in the extent to which domain-general processes, particularly attentional and perceptual processes, play a role in the development of social cognition and theory of mind. In addition, social compliance, particularly in children, may depend on individuals' ability to adopt, maintain, and execute appropriate goals. As a consequence, executive control functions, including working memory, constrain the manifestation of social behaviour, including the impact of social context, parenting and imitation. However, a central problem that has limited progress in this area is the poor specification of executive control, particularly in children. Until recently, working definitions of the construct have relied on a loose collection of putative executive functions. Structural equation modelling has since provided frameworks for organizing these functions, with a focus on updating, inhibition, and shifting, but these still lack a clear theoretical basis. We will therefore examine the development of executive control in children using a principled approach that sets these candidate functions in a theoretical context. This follows directly from two claims: 1) executive function represents the individual's ability to maintain task goals (updating) and to use these to prevent them from acting inappropriately in response to external stimuli (inhibition), and 2) executive control has a temporal aspect that is not independent of previous experience (shifting). We have the expertise to employ precise measures of these functions and, crucially, manipulate them orthogonally to properly test their interplay. Armed with this suite of novel but theoretically-motivated tasks, the relationship between executive control, measures of attention/perception, measures of social context and parenting, and social behaviour will be investigated. We will explore the relationship of executive function in early life and later trajectories of social and cognitive development, social behaviour, and impulsivity and high-risk behaviour. This will be done in a new longitudinal study across three time points over three years. We will also explore atypical groups based on measures of autism spectrum disorder and attention deficit hyperactivity disorder, the developmental trajectories of these traits over time in ALSPAC, and use targeted recall studies of ALSPAC participants who score at the extreme of measures of executive function to investigate cognitive mechanisms in more detail, using both behavioural and fMRI methods.

Workstream 2 (Social Behaviour): This work will examine the developmental pathways, trajectories and psychological mechanisms associated with outcomes in two aspects of social behaviour that have significant societal impacts: sexual behaviour and aggressive behaviour. Life history theory provides a meta-theory for the coherent study of sociosexual and aggressive behaviour at functional, ontogenetic and mechanistic levels. It proposes that timing of important events across the lifespan, and the strategies employed to achieve such goals, are determined by flexible mechanisms that function to increase reproductive success in response to environmental conditions. Human behavioural ecologists have successfully applied this theoretical approach to societally-important issues such age of first reproduction, family size, and parental investment as a function of factors such as socio-economic status and childhood social experiences, and researchers in other disciplines have investigated the neural, endocrinological and psychological mechanisms underlying such behaviour. We will integrate work across these levels of explanation (function, ontogeny, and mechanism), with a particular focus on the development of emotional processing strategies, which play an important role in sexual and aggressive behaviour. Our underlying theory is that biases in emotional processing often reflect adaptive calibration of socio-cognitive mechanisms to the current environment. For example, links between hostile childhood environments and later aggressive behaviour are well established, and may be functional: when exposed to chronically hostile environments in development, aggression may be an adaptive, rather than a maladaptive, strategy in many cases. We will use the ALSPAC cohort to identify emotion processing strategies that mediate the relationships between childhood environments and social outcomes in adolescence and young adulthood. This will allow us to examine trajectory and development of social behaviours, investigating the role of genetic, epigenetic and social/environmental factors (including physical trauma such as head injury) on development. We will use these analyses to design targeted recall studies in the ALSPAC cohort, to investigate underlying psychological mechanisms using both behavioural and fMRI methods.

Workstream 3 (Health and Wellbeing): This work will examine the relationship between social and cognitive development, social behaviour and health behaviour in adolescence and early adulthood. Psychological models of health behaviour have traditionally focused on explicit decisions arising from cognitive appraisal processes. More recently, dual-process models have emerged which integrate evidence that automatic, impulsive processes also play an important (and perhaps dominant) role. Critically, a constellation of high-risk behaviours (e.g., aggressive behaviour, sexual behaviour, substance use) frequently co-occur, and many adolescents engage in these behaviours at levels harmful to health and wellbeing. It is therefore logical to focus on determinants of these multiple risk behaviours, as this may provide single targets for intervention with the potential for broad impact. Current dual-process models argue that interacting, neural systems control decision making, with an impulsive system focused on immediate consequences and a reflective system focused on future prospects. The reflective system governs the impulsive system; however, there are individual differences in the extent to which this is the case, and this is related to executive function. Therefore, factors which influence cognitive and social development in childhood may in turn influence impulsive and high-risk behaviours in adolescence and early adulthood, both directly (via individual differences in executive function) and indirectly (via exposure to peer groups and other environmental risks). We will explore the relationship between cognitive and social development in early life, and subsequent impulsive and high-risk behaviour in adolescence and early adulthood. We will identify the impact of environmental exposures at multiple time points (e.g., tobacco exposure in utero, in childhood in the home, in adolescence in the home and via peer groups) on subsequent impulsive and high-risk behaviours, and explore the mechanistic relationships between these variables using targeted recall methods to enable more intensive characterisation of relevant constructs, epigenetic markers of exposure, and Mendelian randomisation where possible.