Genetics of Human Character and Temperament

Abstract

Personality is the way individuals learn to shape and adapt to changing conditions. The character domain of personality is what people make of themselves intentionally, whereas temperament involves automatic emotional reactivity. Prior studies assuming genes act independently failed to identify most personality‐related genes. Therefore, we used machine learning to identify naturally occurring clusters of genes. In independent genome‐wide association studies from different cultures, we found many replicable multigene clusters among 972 genes that accounted for nearly all the heritability expected from twin studies. Temperament depended on multigene clusters in molecular systems for associative conditioning of habits and emotional reactivity. Character depended on clusters in intentional networks: self‐control of goals via Inositol–Calcium signalling, and self‐awareness of values via long‐non‐coding RNAs unique to modern humans. These three systems of learning and memory allow the integration of habits, goals, and values via the regulation of gene expression to maintain healthy functioning despite variable environmental conditions. Key Concepts The ‘Hidden Heritability Problem’ with complex phenotypes. Human personality is moderately heritable (∼50%) according to many twin and adoption studies, but few of the specific genes for personality were recognised by studies that assumed the genes involved were acting independently. Human character and temperament have a complex architecture: the same gene or cluster of genes can be associated with multiple phenotypes, and different genes or clusters of genes can have the same phenotype. Empirical methods of pattern recognition based on machine learning allow efficient and replicable deconstruction of the complex architecture of human personality. Human personality is a complex phenotype with multiple components. The temperament domain of personality is the disposition of a person to learn how to behave, react emotionally and form attachments automatically by associative conditioning of their habits. Human character is the self‐regulatory domain of personality – that is, the way a person shapes and adapts their goals and values to ever‐changing external and internal conditions. Human character and temperament are each comprised of multiple components that depend on how people function in different situations and environments. Character and Temperament involve adaptive processes of learning, not fixed traits. Human personality is the integrated expression of three genotypic systems that regulate learning and memory by associative conditioning, intentional self‐control and creative self‐awareness. Most of the genes for personality are unique to a single learning system, but there is sufficient overlap to permit integrated functioning. The integration of human character and temperament allows flexible regulation of gene expression to maintain healthy functioning despite variable environments.

Disentangling the personality pathways to well-being

“…According to Cloninger's model of personality 19,20 , subjective experiences are dependent on organizations of psychobiological processes that underlie three distinct but interacting systems of learning and memory that evolved sequentially in human evolution: associative conditioning, intentionality, and self-awareness 24,29,30 . A concise summary of the genetics, neuroscience, and psychology of this research is available 31,32 .…”

Coherence of character and temperament drives personality change toward well being in person-centered therapy

“…Long-term memory of what we learn from experience can give moderate stability to personality, but the capacity for personality change may be reduced, but is not lost, as we age because personality is an expression of systems of learning. Nearly all the heritability for human temperament, character, and the underlying learning systems have been accounted for by specific genes, along with characterization of how they are dynamically and collaboratively organized in clusters and networks [ 5 ▪▪ , 9 , 10 , 12 ▪ , 15 ▪▪ , 16 ]. The 972 genes in all three learning systems are all expressed in the brain and about 70% are also expressed in most organs systems and tissues of the body, so they are positioned to influence all aspects of health (physical, mental, and social) [ 15 ▪▪ ].…”

“…Identification of the genes for personality in modern humans allowed detailed comparisons with the genomes of chimpanzees and Neanderthals [ 5 ▪▪ , 12 ▪ ]. Nearly all (95%) of the 267 genes unique to modern humans were noncoding RNAs that are involved in regulate the expression of protein-coding genes and the co-expression of genes in functional clusters, as well as regulating epigenetic processes.…”

“…The recent findings from genomics and brain mapping provide new insight into the path by which human character develops [ 5 ▪▪ , 12 ▪ , 19 ▪ ]. Longitudinal studies have distinguished 3 stages of self-awareness beyond automatic emotional reactivity [ 20 ].…”

“…Fortunately, recent advances in understanding the biopsychosocial basis and treatment of personality and its disorders offer new fundamental insights that allow us to address these problems in effective person-centered ways [ 12 ▪ ].…”