May 4, 2011
Chimps More Self-Aware Than Previously Believed
A study released today gives insight into the evolutionary origins of consciousness.
Researchers have long understood that chimpanzees are self-aware and can anticipate the impact of their actions on the environment around them, AFP is reporting.
An ability once assumed to be uniquely human, several species of primates and dolphins are able to recognize themselves in a mirror, which would suggest a sophisticated self-awareness.
The study, published in the journal Proceedings of the Royal Society B, consisted of marking an animal with paint in a place -- such as the face -- that it could only perceive while looking at its reflection.
If the subject attempted to touch or wipe off the mark while facing a mirror, it showed that the animal recognized itself. Although this test revealed a certain degree of self-awareness, many questions remained as to how animals were processing the information. Researchers wanted to know what the underlying cognitive process was.
Researchers from the Primate Research Institute in Kyoto, Takaaki Kaneko and Masaki Tomonaga, designed a series of three experiments to see if chimpanzees are able to "think" like humans when they perform certain tasks.
Three female chimps initiated a video game by placing a finger on a touch-sensitive screen and used a trackball to move one of two cursors.
The movement of the second cursor was a recording of gestures made earlier by the same animal and set in motion by the program. The "game" ended when the animal hit a target, or after a certain lapse of time.
At this point in the study, the chimp had to identify with her finger which of the two cursors she had been manipulating. All three animals scored above 90 percent.
"This indicates that the chimpanzees were able to distinguish the cursor actions controlled by themselves from those caused by other factors, even when the physical properties of those actions were almost identical," the researchers explained.
Researchers were still not clear if the performance was due to the ability to discern "self-agency", or to observing visual cues, so the researchers devised another set of conditions.
This time they compared two tests. The first was the same as in the previous experiment. In the second test, both cursors moved independently with no control over them, one a repeat of movements the chimp had generated in an earlier exercise, and the other a repeat of a "decoy" cursor.
The trackball, in essence, was unplugged, and had no connection to the screen.
If the animals performed well on the first test but poorly on the second, it would suggest that they were not simply responding to visual properties but knew they were in control.
The final test, using only the most successful of the subjects, introduced a time delay between trackball and cursor, as if the two were out of sync, and a distortion in the direction the cursor moved.
The results suggested that, "chimpanzees and humans share fundamental cognitive processes underlying the sense of being an independent agent. We provide the first behavioral evidence that chimpanzees can perform distinctions between self and other for external events on the basis of a self-monitoring process."
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