Olivia Judson in the NYT: "First, according to a report published last month in the journal Science, strong political views are correlated with distinct physiological responses to startling noises and threatening images. Specifically, the study found that people who support warrantless searches, wiretapping, military spending and so on were also likely to startle at sudden noises and threatening images. Those who support foreign aid, immigration, gun control and the like tended to have much milder responses to the stimuli. (The study only included people who described themselves as having strong political opinions; the physiology of apathy has not been looked at.)
Second, in other animals, the way an individual responds to threat is part of its personality. If you put a bird like a great tit into a room it’s never seen before, some individuals will be quick to start exploring; others will be slow. Those that are quick to explore also tend to be less skittish at the appearance of a predator. Similarly, if you open the door to a rat’s cage, some animals will be quick to come out; others will be more cautious.
Or, put a dangerous object — like a prod that gives a mild electric shock — into a rat’s cage. On being shocked, some rats will cower in the corner of the cage; others will bury the prod under their bedding. Furthermore — and this is an important link in the argument — an animal’s responses are mediated by aspects of its physiology, like the rate at which stress hormones are released into its bloodstream."
I think the eventual point she makes about obesity and pregnancy is a huge leap, but the scientific studies she cites are interesting. I'm glad humans aren't (usually) born in litters.