As usual, it is about something that is supposed to have accidentally happened to the brain. This time, savanna landscapes:
Compared to the vast emptiness of open water, land is rife with obstacles and occlusions. By providing prey with spaces to hide and predators with cover for sneak attacks, the habitats possible on land may have helped give rise to planning strategies — rather than those based on habit — for many of those animals.
But the researchers found that planning did not give our ancestors the upper hand in all landscapes. The researchers’ simulations show there is a Goldilocks level of barriers — not too few and not too many — to a predator’s perception, in which the advantage of planning really shines. In simple landscapes like open ground or packed landscapes like dense jungle, there was no advantage.
“All animals — on land or in water — had the same amount of time to evolve, so why do land animals have most of the smarts?” asked Northwestern’s Malcolm MacIver, who led the study. “Our work shows that it’s not just about what’s in the head but also about what’s in the environment.”Northwestern University, “Hunting in savanna-like landscapes may have poured jet fuel on brain evolution” at ScienceDaily
Paper. (open access)
But the new savanna theory doesn’t explain much of anything because the question is not why it might be beneficial to be smarter but how exactly it happens.
Incidentally, the theory doesn’t seem to cover squid. See, for example, Is the octopus a second genesis of intelligence? The hardware “has little in common with the mammalian design.” And this from an animal related to oysters. Also: Scientists clash over why octopuses are smart.