Our Brains Are Not Shrinking

False Alarm

Last year a research article made headlines because it reported that starting about 3000 years ago the human brain started shrinking. The authors hypothesized that this may have occurred “from the externalization of knowledge and advantages of group-level decision-making due in part to the advent of social systems of distributed cognition and the storage and sharing of information.” They came up with this conclusion because that is what occurs in ants, ” the insights ants offer can broadly inform us of the selective forces that influence brain size.”

Not So Fast

The fact that the researchers are making a global statement about humans and the fact that the basis for their hypothesis comes from ants suggests that this finding about our brains shrinking should be suspect.

And in fact is should be. A recent research article rebuts this finding. The original article used flawed analyses to arrive at a false conclusions. There has actually been no change in human brain size in the last few thousand years. I am quite sure that this rebuttal will not generate headlines though, unlike the flawed findings of the original article.

Social Sciences Need Discipline

In physics and other physical sciences, experimental results are not trusted unless they have been replicated independently at least once, and preferably more often. This tends to reduce the frequency at which mistaken results are published.

Social sciences need similar self-discipline. This is difficult because the results from social science have more emotional charge and therefore are more likely to be picked up by the popular press. Social scientists also, like most humans, enjoy attention and therefore may promote their work to the public before any independent validation supports their findings. This tendency is compounded when the findings have commercial applications.

None of this is going to change quickly. We can protect ourselves from being misled to some extent by having a doubtful attitude toward social science research that makes global statements about humans or large groups of humans.