May 1, 2011

Monkeys Have Ability To Recall Things Like Humans

New research suggests that monkeys can recollect what they have seen, much like humans.

Scientists found that rhesus monkeys can recall extremely simple shapes from memory, which is evidenced by their ability to reproduce those shapes on a computer touch screen.

The findings suggest that human and monkey memory is more alike than scientists had previously thought.

Recall shows an ability to remember things that are not present in the moment.  It is also necessary for planning and imagining and can increase the flexibility of navigation, social behavior, and other cognitive skills.

Benjamin Basile, of Emory University, said in a statement: "The ability of monkeys to recall these shapes flexibly suggests that they might be able to recollect other types of information that would be useful to them in the wild."

"It's exciting to speculate that they may be able to recollect the appearance of monkeys they know, what favorite foods look like, or the path they would have to take to get to a water source."

He said it is possible that monkeys use their memories in very limited ways.  Basile added: "Maybe it's often just easier to recognize the monkey, the food, or the landmark in front of you."

"What we do know is that they do seem to have the ability to recall information in the lab."

Earlier studies showed that recall and recognition tests given to humans require different types of memory.

For this stude, the researchers trained five rhesus monkeys on a novel recall test in which they had to reproduce a simple figure on a touch screen from memory.

Those shapes included two or three boxes in a grid.  Part of the shape appeared in a different location, and the monkeys had to "draw" in the rest of the shape by touching where the other boxes should be.

The study found that the monkeys remembered less in recall than in recognition tests, even under matched conditions, and recall performance deteriorated more slowly over time.

The researchers said the ability of rhesus monkeys to recall what they have seen in the past suggests that the ability to recollect does not depend on language and may have been present in our common ancestor 30 million years ago.

Basile said in a statement: "Recollection and familiarity likely evolved because they solved functionally incompatible problems."

"For example, familiarity does not support detailed memory for context, but it is quick and resistant to distraction."

"Recollection is slower and more vulnerable to distraction but supports a more detailed and flexible use of memory."

"Familiarity might better allow rapid responses to foods and predators under distracting conditions, whereas recollection might be necessary to access knowledge of distant food locations or past social interactions for planning future behavior."

The study was published in the journal Current Biology.


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