Primatologists studying wild chimpanzees have discovered that they consider almost a dozen different factors when picking out tools. Which you'd kind of expect. What's actually interesting about this discovery is they consider these variables concurrently, altering their preference for one factor based on others. For instance, they'd pick a lighter tool than they might prefer if they knew they had to carry it a long way.
This simultaneous thinking reveals chimps have a much more intelligent decision making process than we thought. It also implies our ancestors with chimp-sized brains were also capable of this; so should get a few extra points added to their IQ.
This research was carried out by primatologists in the Tai National Park, where wild chimps place nuts on a large "anvil" and crack them with a "hammer". The researchers meticulously measured the hammers the chimps chose, along with all the possible hammers they didn't choose. This revealed the chimps use around 9 factors to decide what hammer to use, ranging from hardness to location. In general they preferred the heaviest, hardest hammer they could get their stinkin' paws on.
But the biggest part of these findings is how their preferences changed based on context. If they knew they wouldn't have to carry a hammer very far they picked a heavier one than they would normally go for. On the other hand, if the nuts they wanted were in a tree they opted for a smaller, lighter hammer that would be easy to use in the branches.
This is the fist time this "multi-dimensional" thinking has been seen in the wild; confirming chimps are smarter decision makers than we gave them credit for. And before 2 million years ago our ancestors had chimp-sized brains as well, so likely also had this ability. wee they using "multi-dimensional" thinking to pick out the rocks to make the first stone tools with?
Actually, the real biggest finding of this research is that I'm finally sick of constantly hearing about how "chimps are smarter than we thought." It's decreasing the cognitive gap between us; and really that's all we humans have to be proud of. I'm not happy about it. As such, from now on I'm going to assume chimps are just as smart as humans. That way the real conclusion of studies like this is that chimps are dumber than I thought.
And I can go back to feeling special about being human.
References
Boyd and Silk, 2012 How Humans evolved
Sirianni, G., Mundry, R., & Boesch, C. (2015). When to choose which tool: multidimensional and conditional selection of nut-cracking hammers in wild chimpanzees. Animal Behaviour, 100, 152-165.
