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July 1st, 2009
Spark Blog: Squirrels Bury Nuts, But Are They Planning Ahead?

by Graham Chedd

The Human Spark crew films Alan Alda and Dan Gilbert deep in conversation. Photo: Maggie Villiger

Walking the dog this morning and enjoying the sound of birds singing reminded me of an entertaining exchange Alan had with Dan Gilbert of Harvard University, and author of the book Stumbling on Happiness. The birds sounded happy, but of course we can’t infer that: the real reason for their singing is to find a mate or defend a territory, and so get to pass on the genes for singing.

Dan and Alan were chatting on the Weeks Bridge over the Charles River about Dan’s top pick for what makes us human: the ability to “prospect,” the opposite of retrospect — in other words, to think about the future, “to explore alternative worlds without having to live in them.” While Dan agrees that other animals can look forward in time “in very small amounts,” we do it “orders of magnitude differently and better than any other animal.”

There were acorns on the ground around the bridge, and I’d given one to Alan to remind him to ask Dan a question about whether squirrels are thinking about the coming winter when they bury nuts.

Photo by Diliff, under a CC license

Alan: So what’s the squirrel doing when it plants the nut?

Dan Gilbert: It’s planting a nut, in the here and now, because the day is getting shorter, less light is hitting the little squirrel eye and going into its little squirrel brain, and so it runs the “nut burying program,” in the same way your computer can run programs without thinking about — knowing about the future. You know, if Ben Franklin were to come into the present and see a computer, he would say, there must be a little man inside it. There must be someone inside who knows what to do and what’s going to happen. That would be wrong.

We’re never tempted to anthropomorphize our computers because we understand the circuitry that’s making them run. We don’t understand squirrel circuitry or dog circuitry or cat circuitry well enough, and so we look at the dog, cat and squirrel and say it must know what’s coming, because if I were doing that, I’d do that because I know what’s coming.

Alan: So we assume the squirrel is at an unconscious level mapping where it put the nut, have we found out they just keep digging till they find the nut?

Dan: We can’t know for sure what the squirrel’s doing in its own mind, but I would suggest that squirrels do everything at the unconscious level because they’re not conscious, so everything they’re doing is some sort of program. A squirrel is an amazing automaton. Now that’s not with any disrespect to squirrels…

Alan: If we get letters from squirrels, I’m sending them to you. I don’t want to deal with squirrel letters…

Or chimpanzees, if it comes to that. There is much debate among researchers about whether chimps plan for the future. Mostly this revolves around whether chimps think how they might use a rock or stick in some later task, and the debate’s been further enlivened recently with the report of the chimp in the Danish zoo apparently stockpiling stones to throw at visitors. But even if they do think ahead an hour or two, while that’s more than any other animal that’s been studied, Dan Gilbert is pretty sure they’re not planning for retirement.

– Graham Chedd

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