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”.
