You’re right, I inadvertently inserted that error while editing this post. The sentence the men read is actually part of a longer passage that’s commonly used in speech tests, called “the rainbow passage.” The passage was designed to contain *almost* all the sounds in the English language — apparently it’s got everything except the palatal fricative and the glottal stop. I’ll fix the error in the post.

– Eliza, DISCOVER online news editor

Sheila

What makes EP different is that our hypotheses must pass a strict logical test: the features we posit must have plausibly led to increased reproductive success in our evolutionary past. It is the same test that theories in evolutionary biology must pass.

When people are unfamiliar with evolutionary biology, animal behavior and models of natural selection it often looks like those who use the theories are just making them up. This is not the case. The literature on animal assessment and aggression show that animals, prior to aggression, exaggerate or enhance cues of fighting ability, but they do not hide them. This was noted by Darwin in his Expressions book and has been replicated, documented and predicted in dozens of species since then.

Models of animal aggression show that mutual assessment is selected for. Indeed long “escalating conflicts of assessment” take place between animals in which relatively safe mutual assessment can occur.

If I had studied any species other than humans and documented this ability no one would think to call it a just-so story. It is a clear prediction from a model of evolutionary selection that has already predicted and found this sort of ability in other species.

Thanks for the comments. You both make a good point: the researchers don’t seem to know why certain voices correspond to strength measurements. The test can’t tell them why; it can only show that they do correspond, statistically.

To me, what is also interesting is that the researchers don’t seem to specifically know what it is about the voices that differs; they aren’t necessarily deeper. As Chris says, these all seem like areas for further research.

Carl, your thought about what the authors would have said if the study showed no correlation is also interesting. This paper mentions that previous studies tried to link voice to height and weight and showed no significant link. The study also showed no link between women’s voices and their strength.

For more, the whole study is up here: http://bit.ly/bynIFh

Thanks again for commenting.

“Disguising male formidability would have been important for both sexes over evolutionary time,” said Sell. “Men would have benefitted from disguising who would likely win fights in order to deter aggression and dominance by stronger males and for other reasons. Women would also want this information in order to make effective mate choices, so weaker men would have greater reproductive success if they could eliminate signals that give away weakness. It’s another example of adaptive mimicry so often found in nature.”

Good science starts with a hypothesis, a prediction, and then a test. When your hypothesis — “evolutionary success shapes complex behaviors” — allows you to predict completely contradictory outcomes, then cherry pick the one that matches the outcome, you really don’t have much of a hypothesis.

A more likely explanation? Probably there is a correlation between hormonal levels and strength, aggressiveness, and vocal characteristics.