Rats Know When They’ve Forgotten Something, Says New Research

The study contributes more information on the metacognitive skills of animals.


Credit: Pixabay

Aside from humans, few living species have exemplified metacognition — “awareness and understanding of one’s own thought processes”— in a research setting. Rhesus monkeys, bottlenose dolphins and certain birds, have shown these talents. Now, in a recent study scientists indicates that rats also possess some of these skills, including metamemory.

The study, “Rats know when they remember: transfer of metacognitive responding across odor-based delayed match-to-sample tests” was published in Animal Cognition journal earlier this month. Authors of the study, Victoria L. Templer, Keith A. Lee and Aidan J. Preston, come from Providence College in Rhode Island.


Credit: Pixabay

The experiment used nine adult male rats. The rats were trained to sift through sand and perceive one of four smells— coffee, thyme, paprika, or cinnamon. After perceiving a scent, the rats had to go over and match the smell with the corresponding dish. If they matched the right dish, they received a treat.

Based on “the individual rat’s preference” the reward was either a “FrootLoop (Kellogg’s), Capn’ Crunch (Quaker Oats), or dehydrated marshmallow (Medley Hills Farm).” Food rewards were offered based on a hierarchy. Correct answers equaled an entire treat and wrong answers were not rewarded. However, a third option was offered— rats could select a fifth dish, which had no smell, which would win them one quarter of a treat.

“The statistics showed that when the unscented dish was offered to the rats, the rate of them picking the wrong scent dropped by more than chance alone. This suggests they did indeed know when they had forgotten the scent and would instead opt for the unscented choice to get their quarter treat rather than nothing at all,” IFL Science explains.

Study results also showed that when the rats were allowed to sniff the scent twice, they were more likely to choose the correct dish. If the rats were made to wait between smelling and choosing, they were more likely to “opt out”. Other studies on animals have also shown that species with metacognition will purposely avoid cognition tests that are difficult or annoying. Humans, of course, also present this characteristic.

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