If you get Science, there's a pretty good News Focus item by Elizabeth Pennisi describing recent experiments on animal social intelligence. The background is a little thin, but it is a good overview of recent work, on many different species.
Those studies are beginning, and by looking across the animal kingdom, researchers are gleaning the conditions that predispose a species toward social intelligence. For example, Kay Holekamp, an ethologist at Michigan State University in East Lansing, has observed hyenas for 18 years and concludes that these scavengers can recognize not just their own status relative to the pack leader but also the status relationships of other pack members. Other researchers are trying to measure social intelligence, albeit often in indirect ways, in ungulates, elephants, and dolphins. And in this week's issue of Current Biology, researchers demonstrated that fringe-lipped bats learn to listen for unfamiliar prey from fellow bats.
You do get a flavor of the difficulty of testing cognitive information in nonlinguistic animals, with many clever solutions in experiments. This, for instance, is a study I would not want to participate in:
For example, in a new study in Cognition, Hare and his colleagues designed another competition over food. They had chimps go head-to-head against a human who pulled food out of reach as a chimp went to grab it. If the chimps were given the option, they sneaked up behind a barrier to get to the food instead of approaching it directly. Thus, the chimps demonstrated not only that they knew what the human could see but also that they knew how to manipulate the situation to stay out of sight.
I don't do this kind of thing with my children more than once, and they don't have giant canine teeth.
And there is a note of skepticism:
Galef is particularly skeptical of researchers who have concluded that chimps respond to peer pressure, that wolves and capuchin monkeys have a sense of fairness, or that jackdaws are the avian equivalent of the Good Samaritan. "It's gotten a little out of hand," he complains. And not one species has yet passed the falsebelief test, he points out.
It is really hard to avoid a Clever Hans effect in some of this work -- subtle cues that animals may use that humans cannot pick up on. And the article points that out. It's a good short read on behavior.
