Recently I posted about two papers by Gerald Crabtree who suggested that perhaps human intelligence peaked as hunter-gatherers, and
“that we are losing our intellectual and emotional capabilities because the intricate web of genes endowing us with our brain power is particularly susceptible to mutations and that these mutations are not being selected against in our modern society”.
Apparently it is not politically correct to suggest that humanity might be on a “degenerative” evolutionary path for intelligence and Crabtree’s speculations have been the subject of indignant criticism:
Why Gerald Crabtree’s speculations about declining human intelligence are wrong: …. But like Sanford, Crabtree fails to analyse the problem correctly. In particular, neither show any understanding of quantitative genetics (this is the area of genetics that deals with lots of genes acting on a trait). But unlike young earth creationist Sanford, Crabtree doesn’t even bother to present any data to indicate that an intellectual decline has actually happened.
Discussions and arguments about “intelligence and race” or the “future evolution of intelligence” or “what intelligence is” or whether “intelligence is selected by natural selection” are fascinating but – in evolutionary terms – are largely irrelevant. Evolution is not a force of change. It is the consequences of a response to change, a result – a report-card of what has happened before.
What counts for evolution – both for what has happened before and for what will happen in the future – is which inheritable traits lead to the most begetting. It is in the begetting of offspring that all “selection” lies. This applies both with natural and with artificial selection. All other traits which happen to be present in the individual organisms being reproduced and which are inheritable are only carried along with the ride.
