The working hypothesis described is that one's IQ is determined by the number of deleterious mutations out of perhaps 10,000 possible ones that would have an ef

The working hypothesis described is that one's IQ is determined by the number of deleterious mutations out of perhaps 10,000 possible ones that would have an effect on IQ. So high IQ is a result of a relative lack of negative mutations rather than the presence of positive mutations. This reminds me of the Anna Karenina principle that success is often the result of avoiding all the numerous different ways to fail, named after the opening of the novel: Happy families are all alike; every unhappy family is unhappy in its own way. This theory has a certain appeal. But I wonder how it affects my own personal conclusion (as someone with no background in cognitive science) that the variation in how people think is grossly underestimated—there are people who think exclusively in words, others who think exclusively in pictures. Based on the theory, perhaps these mental variations are influenced by the particular combination of IQ-related mutations, with the brain arriving at the particular way of thinking that is least affected by deleterious mutations.