I believe evolutionary psychology is key to uncovering the origin of individual preferences and values. The Savanna Principle states that the human brain has difficulty comprehending and dealing with entities and situations that did not exist in the ancestral environment. The theory of the evolution of general intelligence suggests that general intelligence evolved as a domain-specific psychological adaptation to solve evolutionarily novel problems. Their logical conjunction suggests a qualification of the Savanna Principle and leads to a new hypothesis about individual preferences and values.The more intelligent people are, the more likely they are to do evolutionary novel things. Like drinking alcohol, smoking cigarettes, and be vegetarian, have sexual affairs, commit less crime, go to bed later, be atheist, and, of course, be politically liberal.
If general intelligence evolved to deal with evolutionarily novel problems, then the human brain’s difficulty in comprehending and dealing with evolutionarily novel entities and situations (proposed in the Savanna Principle) should interact with general intelligence, such that the Savanna Principle holds stronger among less intelligent individuals than among more intelligent individuals. More intelligent individuals should be better able to comprehend and deal with evolutionarily novel (but not evolutionarily familiar) entities and situations than less intelligent individuals.
Some of these observations I don't dispute, but (while I am persuaded that human behavior is influenced by our evolutionary past), I have some trouble believing that it is correct to invoke The Hypothesis so widely. If this principle is true, then why stop at the obvious stuff? (Though I do not think smoking is so obvious, and apparently the data doesn't reflect it, either.)
How about watching TV. Since spending large amounts of time passively watching other people go about their lives is evolutionarily novel, should we not hypothesize that more intelligent people watch more TV? Somehow I have trouble seeing the data coming out in favor of that prediction.
More intelligent people drive cars? There were no cars on the savannah 100,000 years ago. So, intelligent people do it more? Can't wait to see those data.
Shop in supermarkets? Conversely, are people who hunt less intelligent than people who people who don't?
I'll have to admit, though, that coming up with crazy examples - like I trust you'll agree the these are - is far harder than construing examples that are likely to fit with The Hypothesis. Like reading books, traveling, using computers, sitting in offices all day, and having fewer children, or practice BASE jumping. It also neatly fits with the observation that political leaders are so darn dumb.
But then, if you read Kanazawa's post on smoking cigarettes, it turns out not to conform to The Hypothesis. Particularly, in the UK the trend is opposite. The more intelligent people are before the age of 16, the less likely they are to be smokers later in life. Kanazawa plans to address this incongruence in a later post, but I worry that the answer might be some explaining away how smoking really isn't that novel in evolution. Determining what is evolutionarily novel is probably not as straightforward as I have suggested above. They could be lots of exceptions that would render The Hypothesis unusable, I would think, without at least taking lots of other factors into account.
Update 10/23: Kanazawa has a new post about why the correlation between intelligence and smoking is opposite in the US and the UK. Short answer is that he doesn't know. Longer answer is one that he doesn't believe in himself.