Mano Singham has a interesting post up on a large scale review of animal intelligence studies.
Animal intelligence is a fascinating topic and there have been many attempts at studying it.
Many of the individual studies look at one or other specific trait that we associate with intelligence in one species and the traits studied can differ from species to species, making general conclusions hard to arrive at. Ed Yong reports on a massive multinational study that looked across many species at one aspect of intelligence (self control) as demonstrated by two specific tasks. (You can read the paper on which his article is based here.)
What stuck out to me is this quote from the review.
They found a few surprises. For example, the animals’ scores correlated with the absolute but not relative sizes of their brains. In other words, it didn’t matter whether the animals’ brains were big for their size, but whether they were big, full-stop.
I’ve heard or read several times that intelligence was a factor of relative, not absolute brain size. It’s starting to look like the data isn’t backing that up. It reminds me how careful we have to be when accepting conventional wisdom, even scientific conventional wisdom, in areas where there’s not much conclusive evidence yet.
And of course, as Singham notes at the end of his post, there are lots of caveats and controversy with almost all of these studies, most likely starting with the way intelligence gets defined.