Houston: Ravens share the human ability to think abstractly about other minds, adapting their behaviour by attributing their own perceptions to others, a new study has found.
In the study, ravens guarded caches of food against discovery in response to the sounds of other ravens if a nearby peephole was open, even if they did not see another bird.
They did not show the same concern when the peephole was closed, despite the auditory cues, researchers said.
"The findings shed new light on science's understanding of Theory of Mind, the ability to attribute mental states - including vision - to others," said Cameron Buckner from the University of Houston.
Ravens are a good subject for study because despite their obvious evolutionary divergence from humans, their social lives go through several distinct phases, similar to people, researchers said.
In particular, they often defend territories in stable breeding pairs as adults but live in more fluid situations as adolescents.
"There is a time when who is in the pack, who is a friend, who is an enemy can change very rapidly. There are not many other species that demonstrate as much social flexibility. Ravens cooperate well," said Buckner.
"They can compete well. They maintain long-term, monogamous relationships. This all makes them a good place to look for social cognition, because similar social pressures might have driven the evolution of similarly advanced cognitive capacities in very different species," he said.
The study involved two rooms, connected both by windows, which could be opened or covered, and by peepholes, which could be open or closed.
The ravens were trained to look through the peepholes to observe a human experimenter making caches in the adjacent room. During the final phase of the test, both windows were covered but a peephole was open.
A hidden speaker played sounds of a raven competitor, but no other bird was present. The subjects still cached as though they were being watched.
"We show that ravens can generalise from their own experience using the peephole as a pilferer and predict that audible competitors could potentially see their caches (through the peephole)," researchers said.
"Consequently, we argue that they represent 'seeing' in a way that cannot be reduced to the tracking of gaze cues," they
According to researchers, the findings also offers new evidence about the capacities involved in Theory of Mind and abstract thinking.
"It could change our perception of human uniqueness, that we share some of that ability not just with chimpanzees and closely related species but also with a very different species," said Buckner.
The findings were published in the journal Nature Communications.