The Emory researchers overcame the language barrier by teaching the rhesus monkeys to "draw." The monkeys were shown simple two- and three-box shapes on a computer screen. Later, they were presented with a computer touchscreen that allowed them to recreate those shapes by touching the corresponding areas of a grid. The monkeys learned through trial and error that reproducing the shapes they had seen previously would bring a food reward. Once trained, the monkeys were able to transfer their memory skills to novel shapes.
The performance of the monkeys on the computer touchscreen paralleled that of humans using the Rey-Osterrieth Complex Figure Test, a standard human recall test, in which subjects draw a complicated shape from memory.
"Humans certainly recall more complex and sophisticated things over longer time periods," Basile says. "But we've shown that for simple shapes, monkeys have a pattern of performance for recognition and recall that mirrors that of humans. And their ability to immediately transfer their performance to new shapes suggests we're tapping into some general cognitive capacity. With this type of information, we are moving closer to better diagnosing and developing treatments for memory impairments in humans," Basile continues.
Different types of memory may have evolved to solve distinct problems. Recognizing something as familiar, for instance, is quick and might allow for rapid responses to sightings of food and predators. Recollecting absent information is slower, but supports a more detailed and flexible use of memory. The authors speculate that recollection might help monkeys return to out-of-sight places where they previously found food, or to flexibly plan social interactions with other monkeys based on previous behavior.
|Contact: Beverly Clark|