Originally posted on April 28, 2009

Science Daily posted an article today entitled, “Wimps Hear Dangerous Noises Differently”, summarizing the recent work of evolutionary psychologist John Neuhoff.  In the study, Neuhoff asked his subjects to push a button when they perceived that a “looming” sound had arrived directly in front of them.  He then gathered data on the fitness level of each participant and found that less fit individuals hit the button sooner than fit individuals.

The interpretation of these results was that “evolutionary forces” have resulted in weaker individuals who respond more quickly to potential advancing threats.  Stronger individuals can presumably accept a greater level of risk and are therefore willing to allow a threat to approach more closely before responding.

Unfortunately, it seems to me that evolutionary psychologists are often quick to propose an evolutionary advantage without first thoroughly exploring all other possibilities.  Claiming that evolutionary forces have resulted in these observed trends is to assert that a genetic mechanism (as evolution is, after all, just changes in gene frequencies across generations) is driving the finding that wimps perceive looming sounds to have arrived in front of them sooner than more fit individuals.

While there certainly could be a genetic component to their finding, the authors did not seem to consider the influence of learning and early experience on the expression of these behaviors.  Perhaps the more fit individuals have simply learned that they have little to fear (especially in our current environment in which predators on humans are rare) and have therefore learned to be less responsive to looming sounds.  On the other hand, wimps may pay attention to these sounds as they may have learned long ago that risks to their safety (more fit bullies, for example) are present in the environment, requiring them to be more mindful of their surroundings.

The study has not yet been published in its entirety online, but I’d be interested in seeing if the authors addressed this issue in their discussion.  The importance of learning and early experience could potentially be addressed through surveys that seek to determine how risky the participants believe their environment to be and how this level of risk correlates with negative experiences, such as getting beaten up as a kid, being mugged, experiencing an attack from a dog, etc.

The interpretation of these results may also be downplaying the negative effects of differences in the onset and frequency of responses to looming sounds.  Previous studies have shown that looming sounds activate parts of the brain which warn of impending danger.  If even looming sounds played in the safety of a lab elicit warning responses, then we may expect that high responding wimps perceive that they’re in danger more often than fit individuals.  Consistently high levels of stress (like those associated with frequently believing that you’re in danger) are linked to susceptibility to a slew of diseases, indicating that this behavior may not be entirely beneficial.

I found the results of the study to be really interesting in general, but would like to see more information on the mechanisms generating these behavioral differences in the future.