Human nature, cultural diversity and evolutionary theory

Human nature, cultural diversity and evolutionary theory

"If one man in a tribe... invented a new snare or weapon, the tribe would increase in number, spread, and supplant other tribes. In a tribe thus rendered more numerous there would always be a rather better chance of the birth of other superior and inventive members."[3][4]

More than 40 years ago, the ethologist Konrad Lorenz wrote that ‘the stratified structure of the whole world of organisms absolutely forbids the conceptualization of living systems or life processes in terms of ‘disjunctive’—that is to say, mutually exclusive—concepts. It is nonsense to oppose to each other—‘animal’ and ‘man’, ‘nature’ and ‘culture’, ‘innate programming’ and ‘learning’—as if the old logical diagram of alpha and non-alpha were applicable to them…human nature persists in and is the basis of culture; and all learning is very specifically innately programmed’ [1, pp. 20–21].

Human culture, the most complex phenomenon on the planet, comprises many entities, some of which are indeed simple motor behaviours, but others are complex higher order knowledge structures (HOKS) such as the concepts of schools or shops, and yet others embody beliefs and values within social constructions like patriotism and marriage, which only exist because individual humans believe in such things. Belief is a complex set of psychological states caused by currently poorly understood psychological mechanisms and serving as yet unknown evolutionary ends. Nonetheless, social constructions have enormous causal force in human affairs and are one of the most potent engines of human diversity. 

Learning, the process by which behaviour becomes adapted to local environmental circumstances which change faster than evolution acting only on gene pools can adjust to, is one possible solution to Waddington's uncertain futures problem.

Most forms of learning, then, gain knowledge that forms the basis of adaptive behavioural adjustment, which the main evolutionary programme cannot keep up with, even though evolution almost always points the learning processes to what, in general, needs to be learned. The evidence for evolutionary constraints on learning, including human learning, is overwhelming [7] and has given rise to notions such as ‘the instinct to learn’ [8].

There is a causal relationship between the individual gain of knowledge and the wider context of the collective knowledge of a species that exerts constraints on learning by way of the gene pool....Learning places causal explanations for adaptive behaviours as much within the neural network mechanisms that govern learned behaviour as they do within the genetic and developmental mechanisms which constrain that learning.

These are animals of a single species that are acquiring different behaviours common to geographically isolated groups by way of learning mechanisms sited in the neural networks of individual animals. That such learning mechanisms have evolved, presumably from more basic forms of learning, is not in doubt; that they are subject to innate constraints is not in question; that they cannot be explained by some form of genetic reductionism is clear; and that they add to the diversity existing within this species is obvious.

As will be argued below, singling out language as the defining feature of human evolution is probably incorrect. Human language as a form of communication is a uniquely human trait, but it is what is being communicated that is as important as the means of communication, and what is being transmitted from human to human, the heart of human culture, is at once a product of learning and occurs by way of learning. 

Memories are constantly changing as we rework and reinterpret our memories, in part because our goals and wishes reshape our memories as expectations of our past, and partly through the effects of unconscious generic knowledge structures, culturally determined, that form the anchoring points around which memory is structured. 

Money and ideology are examples of social constructions that rule, and often destroy, the lives of almost all living humans.

Evolution is a set of historical processes, which means that the past always constrains the present; this applies in both the phylogenetic and ontogenetic realms. As Gould liked to point out, Darwin taught us that history matters, and it matters in imposing limits on what evolution can give rise to. However, it takes time for constraints and limitations to evolve.