Study shows that ravens have “Theory of Mind,” something that was thought only humans had.
Ever wondered what it might be like to see things as a cat, or dog, or as your favourite animal? Turns out that ravens can do the same – though at a much simpler level.
This is called “Theory of Mind (ToM),” and is a trait that has been proposed to exist in certain great ape species as well as several monkeys.
The study was led by Dr. Thomas Bugnyar of the University of Vienna, and it involved testing a number of ravens in a laboratory setting – using two rooms separated by a small peep-hole. The test-subject would be placed in one of the rooms, alongside a stash of food.
Ravens will guard their food stash whenever they see other ravens nearby. However, they WON’T engage in that behaviour if they can only hear raven-calls. In the room with its stash, the raven showed no such behaviour so long as the peep-hole was kept shut as raven-calls were coming from the other room next door.
Once the peep-hole was opened, though, and the test-raven could glance into that other room, then the guarding actions began.
What makes this an example of ToM, and not simply defensive behaviour as has been proposed, among other things such as familial behaviour – especially with primates – is that the sounds were mere recordings on tape. The test-raven had no visual confirmation that there was indeed another raven in that other room hungry for its food, yet it would still act as if there was; perhaps thinking that the would-be raven was hiding just out of its range of vision through that tiny peep-hole.
If this study is as unique as it is claimed to be, then it certainly stands as another, little piece of evidence that we humans are not as uniquely endowed mentally as we’ve always thought. While ravens’ ToM is currently restricted to other corvids, the fact that ravens are able to conceive that another bird could be watching them is in itself an important discovery.
The next step from here is likely to re-evaluate this cognitive ability in primates, and also to see if other intelligent animals such as dolphins and octopi have this trait. Finally, since we presently do not know when this trait first expresses in our own species, to actually conduct this sort of test on human infants should also be worth-while.
Another avenue to take here would be to try to figure out what kind of evolutionary steps are usually required in order for the first inklings of ToM appear in a species, although certainly there are a number of hypotheses out there proposed already – for example, in Bugnyar’s study in particular, it is offered that being able to predict which food sources may be competed over in a given season or year is an important, likely primary evolutionary advantage that can certainly aid in the particular raven’s ability to ensure it can always have access to sufficient sustenance.
Bugnyar, T., Reber, S., & Buckner, C. (2016). Ravens attribute visual access to unseen competitors Nature Communications, 7 DOI: 10.1038/ncomms10506
Image Credit: Ingrid Taylar / Flickr