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February 24, 2007
Time traveling birds
If anyone still needed to be convinced that birds are strange, strange creatures - creatures bizarrely capable of much of what we consider to be inherently human behavior - they need only grok the recent collapse of the Bischof-Kohler hypothesis [1] (tip to New Scientist). Of course, if you're like me, you hadn't heard of the B-K hypothesis previously, and its collapse would have gone completely unnoticed except for my ongoing fascination with bird brains. In a brief letter to Nature, four experimental psychologists describe a simple experiment with western scrub-jays (Aphelocoma californica). The experiment [2] regulated the amount of food available to the jays in the evening and the mornings; on one morning, the jays would be given no food, but on the previous evening they were given more food than they needed. The jays spontaneously and consistently cached some of that extra food for the following morning, when they would be hungry and without food. The researchers say,
These results challenge the Bischof-Kohler hypothesis by demonstrating that caching on one day was controlled by the next day's motivational state and available resources.
So, we can now add time travel to the growing list of human-like behaviors that birds seem to exhibit (others include rudimentary language, basic knowledge of the integers, creativity, tool use, object permanence, cause-and-effect, and that most human of behaviors, deception). I also find it interesting that birds typically only exhibit one or a few of these abilities, suggesting not only that they are located or controlled by different parts of their brains, but also that they are not all essential to survival. It certainly wouldn't surprise me if these behaviors turned out to be a lot more common in the animal world than we give them credit.
Update, April 3, 2007: Carl Zimmer writes in the New York Times Science section about different kinds of time-traveling behavior in several species (including rats, monkeys and humans), and writes at length about the scrub jay's abilities. He also blogs about his article and links to some of the recent science on the topic. End Update
Raby, Alexis, Dickinson and Clayton, "Planning for the future by western scrub-jays." Nature 445 919-921 (2007).
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[1] The Bischof-Kohler hypothesis says, in short, that the ability to (mentally) travel in time is uniquely human. It's clear that humans can do this because we talk about it all the time - we can call up vivid, episodic memories of past experiences or make complex plans for future contingencies in a way not reminiscent of operant conditioning. Since animals can't talk to us directly, we can only hope for indirect evidence that animals can (mentall) time travel. There's some evidence that primates can time travel (for instance), but since they're our cousins anyway, perhaps that's not too surprising. Given the complexity of their behavior, I imagine that elephants would also pass the time-travel test.
[2] I find it amusing that the researchers called their experiment "planning for breakfast," but maybe that's because normally scientific prose is so filled with jargon that a completely sensicle and common name for a scientific term seems like a bolt out of the blue.
posted February 24, 2007 08:37 AM in Obsession with birds | permalink