Genetics of Human Social Behaviour

Abstract

Abstract Our species, Homo sapiens , displays the most multifaceted social behaviour ever to evolve, far exceeding all other social species from eusocial insects to our nearest primate relatives. This intricate social behaviour underpins our remarkable success in evolving from cooperation in small bands of hunter gatherers ∼100 000 years ago to the apex of globalisation that characterises the twenty‐first century political and economic institutions. Although our social brains are remarkably flexible, a significant part of our social behaviour is hardwired and embedded in our deoxyribonucleic acid (DNA) code. The human mind is not a tabula rasa , and our behaviour is constrained to a significant extent by our genes. That is not to say that environment is unimportant; along with the genetic code, the interaction between environment and genes makes us who we are. The overall role of genes and environment is revealed firstly by twin studies and then by leveraging the human genome project. The latter enables the identification of specific genes that, together with the environment, contribute to individual differences in human social behaviour. Key Concepts: Twin studies demonstrate that both genes and environment more or less equally contribute to individual differences in almost all human behaviour. Diverse social phenotypes such as pair bonding, parenting, fairness, altruism, trust, economic behaviour, political attitudes and others are partially hardwired. Two nonapeptide hormones, oxytocin (OT) and arginine vasopressin (AVP), are paramount human social hormones and have been the focus of attention of studies based on translational evidence from rodents, especially the vole. Candidate gene association studies have provisionally shown that genes in the AVP and OT neural pathways also contribute to human social behaviour. Other neural pathways and their associated genes, especially dopamine and serotonin, have also been identified and linked to human social behaviour. Neuroeconomics, which employs the principles and techniques of behavioural economic games, paves the way towards finding common polymorphisms by employing economic games as phenotypes in molecular genetic studies. Genome‐wide association studies (GWAS), which are agnostic and hypothesis free, offer the opportunity to identify many novel genes contributing to human social behaviour. To leverage the power of GWAS and discover new ‘social’ genes, sharpened phenotypes such as incentivised laboratory ‘games’ need to be employed. Such laboratory‐based phenotypes strategically go beyond pencil and paper questionnaires ideally employed in panel studies and surveys.