Social Learning in Antisocial Animals

In an unusual study with potentially revolutionary implications, Austrian biologists Wilkinson et al show evidence of Social learning in a non-social reptile.

Social learning means learning to do something by observing others doing it, rather than by doing it yourself. Many sociable animal species, including mammals, birds and even insects, have shown the ability to learn by observing others doing things. It's often seen as a distinct form of cognition, separate to "normal" learning, which evolved to facilitate group living. It's one of the things that everyone's favorite brain cells, mirror neurons, have been invoked to explain.

But if observational learning is a specifically social adaptation, then non-social animals would be predicted to lack this ability. One distinctly unfriendly species is the South American red-footed tortoise (Geochelone carbonaria). In the wild, they hatch from their eggs alone, and get no parental care; they live most of their lives without interacting with others.

Wilkinson et al found that red-footed tortoises can, nevertheless, learn by observation. They took four tortoises and got them to watch another "demonstrator" tortoise completing a difficult task: walking around an obstacle to get to some food (it's hard if you're a tortoise).

The observing animals all learned to do the task. In most cases, they walked around the obstacle to the right, which is what the demonstrators did, but sometimes they went left, showing that they were not simply copying the movements of the demonstrators. The wood chips on the floor of the floor of the cage were mixed up after each trial, to rule out the possibility that the tortoises were just following the smell of the demonstrator. None of four control tortoises, who got no demonstrations, managed to figure it out on their own.

The authors conclude that

The dominant hypothesis in this field claims that social learning evolved as a result of social living and therefore predicts that the tortoises would have difficulty with this task. They did not. The findings suggest that, in this case, social learning may be the result of a general ability to learn. Although the brain mechanisms that underlie the tortoises’ ability to learn socially remain unclear, it seems most likely that it is the product of a general learning mechanism that allows the tortoises to learn, through associative processes, to use the behaviour of another animal just as they would learn to use any cue in the environment.

This is a nice experiment, and the result is important: the idea that social learning is somehow evolutionarily and neurally "special" underlies a lot of modern social neuroscience. However, I'm not convinced that these tortoises can be accurately described as "non-social". Even the most anti-social species have to socialize in order to mate: no animal is an island. According to Wikipedia the red-footed tortoise has some quite elaborate (and hilarious) mating behaviours...

male to male combat is important in inducing breeding in redfoots. Male to male combat begins with a round of head bobbing from each male involved, and then proceeds to a wresting match where the males attempt to turn one another over. The succeeding male (usually the largest male) then attempts to mate with the females. The ritualistic head movements displayed by male red-foots are thought to be a method of species recognition. Other tortoise species have different challenging head movements....The unique body shape of the male redfooted tortoise facilitates the mating process by allowing him to maintain his balance during copulation while the female walks around, seemingly attempting to dislodge the male by walking under low-hanging vegetation.

Wilkinson, A., Kuenstner, K., Mueller, J., & Huber, L. (2010). Social learning in a non-social reptile (Geochelone carbonaria) Biology Letters DOI: 10.1098/rsbl.2010.0092