Tuesday, April 22, 2014

Ants are just as clever (and stupid) as people.

Last week I found out that Takao Sasaki was one of the winners of this year's Glushko prize for cognitive science. The prize is awarded by the Cognitive Science Society, whose overall aim is to further understanding of the human mind. Given this, it was very gracious of them to give the prize to Takao. His PhD thesis wasn't really about the human mind. Instead, it was dedicated to showing that rock ants are just as smart as humans. Or, when working as a colony, possibly even smarter.

One ant carries another to her new home
Takao started with rationality. Over the last decade economists have been gradually discovering, what any bloke in the pub could have told them for free, that humans are not rational. For example, one thing retailers often do to fool us irrational mortals is place out a number of unattractive decoy products which make the product they want you to buy seem like a better deal. Takao did the same with his ants. He found that individual ants changed their preferences for the nest they would like to live in when offered an additional option. Ants are just as malleable as we are. But it turned out that the ant colony as a whole was not swayed by irrelevant options. A bit like when you come home from a shopping trip and your family asks you "why the hell did you buy that?", the colony is a whole is more sensible than any of the individuals in it.

Individual ants can choose between a good and a bad nest
site, but have difficulty with eight. Colonies have no
problems with either set up. 
One explanation for irrationality in individual ants may lie in differences in cognitive capacity between groups and individuals. In his next experiment, Takao tested how individuals and colonies performed when offered large numbers of potential homes, some good and some bad. The colonies seldom chose a bad nest, but the individuals did so nearly 50% of the time. When compared to groups, individuals are not only irrational but downright bad decision-makers.

So groups are better than individuals? The crowd is always wise? Well, not always. Next Takao looked at how decision-making difficulty affects the ability of colonies to choose the best of two nests. He showed that, as in his earlier work, the colony was better than the individual at choosing when a difficult decision had to be made. But when the decision was straightforward, and one of the potential homes was a lot better than the other, the colonies got it wrong more often than the individuals.

Takao's latest paper is on learning. When ants repeatedly experience, for example, very light nests (which they like), then they put a premium on very dark nests. On the other hand, if they experience, nests with large entrances (again something they don't line), then they put a premium on narrow entrances. Again the ants are a bit like us.

Takao's PhD supervisor and co-author on the above work is Stephen Pratt, who I have known and worked with for many years. Stephen and my work together focussed more on the mechanisms these ants use to make good group decisions. Takao's thesis really takes a whole new direction by testing ideas from cognitive science on ants, and I think the award is very fitting. Well done!

And don't worry if you happen to be human. One day we will prove that we are smarter than ants, but we are still a long way off.

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