I feel your pain. I respectfully disagree. Once the self-reflective self developed then cultural elements advanced extremely rapidly. Regarding IQ; it's a culture test, always has been just like the SAT test. The way youngsters deal with information is very different from 50 years ago, somuchso that IQ tests are all but irrelevant nowadays. A lot of sense here, and I see the results of this at the university level (where the same 'educational' paradigms dominate); trying to get students to think critically or creatively is possible, but takes a real effort on the teacher's part because the students have come out of secondary school systems which are wholey prescriptive and modular (in a closed manner). Basically, Don has given a decent overview however I would add that the environment (culture) plays a massive part in a child's development; our genetic makeup is a design that does unfold according to our environment (within genetically endowed limits - but these limits allow a lot of diversity). On a simple level, all babies/young children are capable of developing all the language sounds contained within all languages, but by the age of 4 or 5 the neurons that enable this flexibility are already specializing in the sounds within their environment (i.e. languages they are exposed to), and thereafter are limited in which sounds they can make; the environment has altered their brains. This is true not just in language, but in every aspect that the environment is sensed and thus acted upon. So, we have two fully integrated parts: 1) Genetic endowment. 2) Environment. 'Traditional' scientists have massively underappreciated the latter although the last few decades have turned that on its head. This has been detailed very well in neural constructivism. How do minds emerge from developing brains? According to "neural constructivism," the representational features of cortex are built from the dynamic interaction between neural growth mechanisms and environmentally derived neural activity. Contrary to popular selectionist models that emphasize regressive mechanisms, the neurobiological evidence suggests that this growth is a progressive increase in the representational properties of cortex. The interaction between the environment and neural growth results in a flexible type of learning: "constructive learning" minimizes the need for prespecification in accordance with recent neurobiological evidence that the developing cerebral cortex is largely free of domain-specific structure. Instead, the representational properties of cortex are built by the nature of the problem domain confronting it. This uniquely powerful and general learning strategy undermines the central assumption of classical learnability theory, that the learning properties of a system can be deduced from a fixed computational architecture. Neural constructivism suggests that the evolutionary emergence of neocortex in mammals is a progression toward more flexible representational structures, in contrast to the popular view of cortical evolution as an increase in innate, specialized circuits. Human cortical postnatal development is also more extensive and protracted than generally supposed, suggesting that cortex has evolved so as to maximize the capacity of environmental structure to shape its structure and function through constructive learning. https://www.ncbi.nlm.nih.gov/pubmed/10097006 So, yes, as our environment becomes an inane place, people evolve according to the social needs/cultural environment - which, I think, is what Biddlin said in his first post?