On the evolution of lying

I came across another striking story in Hurford (see 31st July) yesterday, this one concerning baboons, retold from Domb & Pagel's original article of 2002 in Nature 410. It seems that the female's highly visible sexual swellings are reliable indicators of her reliability as a mate: females with big swellings have lots of children, they have good quality reproductive apparatus. So far so good: males can choose females on the basis of swellings, male success in fighting off other males is a good indicator of fitness in other respects and so the swellings do indeed help the best males mate with the best females, this being widely thought to be the best way for a species to thrive and survive.

But then suppose that nature decides at some point that putting all this investment into swellings is a bit wasteful and that it would be more economical, better, for females to signal their reproductive fitness by a special sort of grunting, a grunting which only requires a bit of training of the vocal apparatus, apparatus which has already been put in place for other reasons, apparatus which does not require a lot of energy in construction or maintenance. In business-speak, nature leverages its investment in vocal apparatus.

At first all goes well, swellings are off but, instead, reliability as a mate is reliably indicated by grunting.

But then the female baboon brain, already quite large for other reasons, finds out that, with a bit of time, effort & application, she is able to fake. Enterprising baboons set up schools for faking, possibly public schools (in the English sense of the word), open only to baboons with money. The question then is what sort of indicator of mating reliability does grunting become?

It might be a good deal for the females because it enables them to catch better mates than they might have otherwise. It might be a bad deal for the males because they are swindled - at least if being a brainy female baboon does not confer reproductive advantage in some other, compensating, way. One could spend happy years modelling such stuff on one's computer.

But in any event, I think it likely that Mother Nature would have given it a go, and so set the Original Lie in motion, never to look back.