May 7, 2021, 11:30–12:30
Human nature, at a species level, is encoded in our DNA. The broad profile of behavioural tendencies and cognitive capacities that defines us as humans arises from a genetic program that specifies the development and wiring of a human brain. However, this program differs between individuals, resulting in individual differences in the wiring of our brains, which manifest in turn as differences in our individual profiles of psychological traits. Large-scale behavioural genetic studies confirm that a significant proportion of the variance observed in psychological traits across the population is due to genetic differences (i.e., these traits are substantially “heritable”). However, the genes involved are not “genes for intelligence” or “genes for neuroticism” or “genes for schizophrenia” – they are genes for building a brain, or, more accurately, they are genetic variants that affect the complex processes by which the brain self-assembles. The relationship to cognitive functions and psychological traits is thus highly indirect and emergent. Moreover, genetic differences are not the only sources of variation in brain development. The processes of neural development themselves are inherently stochastic, leading to both quantitative and qualitative variation in outcomes, even from the identical genome. Genetic variation and developmental variation thus combine to cause variation in the way our brains are wired, manifesting as differences in our innate psychological predispositions. In turn, these predispositions influence our experiences and our subjective responses to those experiences in a way that continues to shape the emergence of our individual character and habits over our lifetimes.
Kévin Mitchell (Trinity College Dublin), “The Developmental Origins of Our Psychological Traits”, IAST General Seminar, Toulouse: IAST, May 7, 2021, 11:30–12:30, room Zoom.