Are they overconfident in their study of overconfidence?

A “Nature” paper is treated like a solid fact in most undergraduate communities. But here we are challenging the Dominic Johnstone’s paper, “The evolution of overconfidence”. In this study they show that relative to the amount of uncertainty regarding the opponent’s capabilities, it is evolutionary plausible that individuals be overconfident and overestimate their own capabilities. In simple words they say that if you are not sure that the other one will win, it is better to get up and enter the fight [BTW: does this qualify as a 3-minute version?].

Claire El Mouden has criticized this study in her blog post, going as far as pitying that it even passed the peer-review process. What amused me as much as El Mouden was how olden are the computational studies of animal conflict. A cursory search brought up studies with similar methodology and results dating back to 60s and 70s. However El Mouden’s main argument in criticizing the current study was that the authors’ novel bias term, “K”, is not equal to confidence and they have over-interpreted it. Bahador exemplified the argument by asking that if we applied the model to increasingly simpler organisms (cows, insects, Amebae) would it still be appropriate to regard the “K” as a measure of confidence? At first I felt tricked by the authors. I thought they managed to sell me a colored-Gonjeshk as Ghanari! But I’ve got some justification that their interpretation can still be defended.

Before projecting the scenario to simple organisms’ ecology, it is important to pay attention to the model’s assumptions. To quote the paper:

“Individuals choose whether or not to claim a resource on the basis of their perceived capability relative to the capability of other claimants.”

So the individual that we are modeling is capable of perceiving his own capabilities, and perceiving his opponent’s capability, and is capable of making informed decisions as to whether claim the resource or not. The Amebae might be able to calculate a signifier of his own capability and retreat from approaching the resource if obstacles turn out to surpass his capacity. But I highly doubt that Amebae be able to calculate another Ameba’s capabilities and then decide accordingly! So I’m saying that an organism that fits those assumed criteria, can also be credited to be perceptually biased in one way or another (i.e. over or underestimating capabilities; hence being over or under-confident). I do not find anything wrong with calling the “K” overconfidence, as long as you take the model’s presumptions into account. We also shall remember that this study is a modeling of conflict between two individuals. It is not a model of approaching resources in environment. The model does not consider any cost for approaching resources per se (if you claim and no one else does, you will gain and pay no cost). So this is not an exact replica of early studies that show when cost of claiming a resource decreases, more individuals would approach it (a ripe fruit at a 10cm distance is more frequently claimed compared by a fruit on the other side of a wide dangerous valley). At least we can say this study is applying similar calculations to the issue of inter-individual conflicts, but is not the same.

Next comes the argument that the study’s findings are dated. Despite the huge literature of animal conflict, they does not discuss the biased perception of capabilities per se. Take the 1976 study of John Maynard Smith for instance. Therein they discuss several scenarios of asymmetric conflicts and yet none is about a biased self-deception. They actually conclude that in an asymmetric conflict it is best to obey the cue features and settle the conflict without even entering a fight, thereby precluding costs altogether. To my interest the same paradigm of thought lives on in widespread recent scientific works. The other day I was reading a chapter from Jared Diamond’s book, “why is sex fun?”. In a chapter on physical body signals, he proclaims that in a conflict accurate exchange of knowledge about each one’s capabilities would benefit either individuals:

“It would be advantageous to both individuals to exchange signals that accurately indicate their relative strength, and hence the likely outcome of a fight. By avoiding a fight, the weaker individual is spared the likelihood of injury or death, while the stronger individual saves energy and risk”

The argument sound intuitive and the author expect us to take it for granted. But the current study demonstrates that this framework of thought is not necessarily true. In situations that claiming is not relatively costly it is more rewarding to be biased and over confident and enter conflicts against the odds; even though that the cost might be larger than benefit in a single confrontation, as the calculations showed that benefit to cost ratio critical point for over-confidence is r/c > 0.7.

All in all, I do not find the terminology of equalizing a positive “K” and overconfidence, wrong, but it is true that the results are not that novel theoretically. Someone familiar with the literature on animal conflict would not be that much astonished by this study. But Johnson and Fowler were (over-)confident enough to claim this and apparently no one in Nature’s editorial board stepped in for a conflict. The odds were on their side and they published this not so much phenomenal finding in Nature. As it turns out “Fortune favours the bold”.