Some birds are smarter than others. Crows, for example, are seen as having a relatively high intelligence. Previous studies have shown that crows can recall human faces, manipulate tools, they are able to remember large numbers of feeding sites, they can plan their social behavior according to what other members of their group do; and they are capable of communicating with one another in fairly sophisticated ways. Evidence also suggests that they are one of the few non-human animals capable of displacement (communicating about things that are happening in a different spatial or temporal location to the here and now).
A new study puts the brain power of crows on a higher level still. Crows can seemingly solve higher-order, relational-matching tasks.
For the research project, two hooded crows, that were at least two years old, were used. The two crows were subjected to a series of observational assessments. To start with, the crows were trained and tested to identify items by color, shape, and number of single samples.
For this the crows were placed into a cage. Inside the cage was a dish containing three small cups. At intervals, objects were placed into the cups. The sample cup in the middle was covered with a small card on which was pictured a color, shape or number of items. The other two cups were also covered with cards. One card was the same as the sample and the other card did not. During the initial assessment, the cup with the matching card contained two mealworms; the crows were rewarded with the worms when they chose the matching card. However, if they failed they were not given any food.
With the second component of the study, the crows were assessed with relational matching pairs of items. Here neither test pairs exactly matched the sample pair. Then purpose of this was to avoid control by physical identity. For instance, the crows might have to choose two same-sized circles rather than two different-sized circles when the sample card displayed two same-sized squares.
Remarkably the birds correctly performed the relational matches, and did so spontaneously. This was partly a product of their learning from the first study, an “identity matching-to-sample” test. To test out the results further and to see if they are reproducible, additional tests on different crows will be undertaken.
The findings have been published in the journal Current Biology, in a paper titled “Crows Spontaneously Exhibit Analogical Reasoning.”
