Genes, evolution and intelligence.

TL;DR: It is argued that the g factor meets the fundamental criteria of a scientific construct more fully than any other conception of intelligence and suggests that many species have evolved a general-purpose mechanism for dealing with the environments in which they evolved.

Abstract: I argue that the g factor meets the fundamental criteria of a scientific construct more fully than any other conception of intelligence I briefly discuss the evidence regarding the relationship of brain size to intelligence A review of a large body of evidence demonstrates that there is a g factor in a wide range of species and that, in the species studied, it relates to brain size and is heritable These findings suggest that many species have evolved a general-purpose mechanism (a general biological intelli- gence) for dealing with the environments in which they evolved In spite of numerous studies with considerable statistical power, we know of very few genes that influence g and the effects are very small Nevertheless, g appears to be highly polygenic Given the complexity of the human brain, it is not surprising that that one of its primary fac- ulties—intelligence—is best explained by the near infini- tesimal model of quantitative genetics