Is risk-aversion bad for you?

It is bad for rats, or so it seems:

…new research published in the Proceedings of the National Academy of Science shows that caution can actually kill you. Sonia Cavigelli and Martha McClintock of the Department of Psychology and Institute for Mind and Biology at the University of Chicago found in a recent experiment that individuals who fear novelty–a condition scientists have named “neophobia”–are likelier to die at an earlier age than those who are unafraid of change. It is the first time, says Cavigelli, that a study has demonstrated that an emotional trait that shows up in infancy can shorten life span.

For this research, Cavigelli and McClintock followed the lives and fortunes of pairs of rat brothers for several years. The scientists chose their subjects by first establishing which of the rats were neophobic. To do this, they placed the young rats inside a bowl in a small room. Objects the rats hadn’t seen before–a rock, a metal box, and a plastic tunnel–were placed in each corner of the room. The rats the scientists deemed neophobic either stayed hunkered down in the bowl or left it only hesitantly, with hunched backs, stilted walks, and bristling fur. The rats who left the bowl quickly to explore the room and the various unfamiliar objects were dubbed neophilic.

And the results? These risk-averse rats showed a consistent pattern of stress throughout their lives and died at earlier ages. What does this mean for people?

A number of parallels exist between humans and their rat surrogates. Neophobia shows up in human infants as early as 14 months of age, and like the rats, fearful children have a faster and stronger hormonal response than children who are not afraid of new situations. It’s also been shown that if you are neophobic at a young age, you tend to remain that way throughout childhood. Cavigelli suggests, however, that individuals may develop strategies to avoid the negative effects of neophobia. “If you are a neophobic-type person, you might avoid any novel situations thereby minimizing that stress,” she says. Staying away from stressful situations could be a form of “self-medication.”…The wear and tear of stress hormones can cause neophobes to get sick more quickly, suggests Cavigelli. So if you know you’re a neophobe–and therefore more vulnerable to any bug going around–you might want to be seek medical intervention promptly in the case of illness.

Although it looks like the neophiles have an unfair advantage, they may not have it as good as it seems. In the experiment, Cavigelli and McClintock played God by controlling the environment of their subjects and essentially creating a safe universe where being brave didn’t get you into trouble. But real life, with its car accidents, plane crashes, and human predators does not always reward the fearless. Human neophiles might also have longer lives if we were all just rats in a cage.

The researchers suggest that it makes evolutionary sense for mothers to have emotionally diverse litters. In other words, there is an evolutionary reason why some but not all teenagers can act like such foolish idiots. See Slate.com for the full story.