New Caledonian crows prove capable of yet another cognitive
feat--inferring the actions of hidden people.
By Jef Akst
September 18, 2012
Already famous for their impressive problem solving skills, New
Caledonian crows can now add logical inference to their repertoire. Alex
Taylor of the University of Auckland in New Zealand placed a box with food
near a hanging blue sheet, behind which someone could hide. A stick
protruded from the sheet. Crows watched as people walked behind the sheet,
then saw the stick move, and finally saw the people leave.
seemed to make sense to them. But if they saw the stick and box move without
observing someone enter and exit the hideaway, the crows became more
cautious, exploring the blue sheet instead of probing the box for food. (See
a video of this behavior at
ScienceNOW.) According to the researchers, the crows had likely inferred
that if the stick was capable of moving, and no human left, maybe it could
"We show that tool-making New Caledonian crows react
differently to an observable event when it is caused by a hidden causal
agent" than by an agent that could be seen or inferred, the authors wrote in
Proceedings of the National Academy of Sciences, where they published
their results yesterday (September 17). "This difference shows that the
crows can reason about a hidden causal agent"--a cognitive ability
previously only attributed to humans.