Editing Metacognition (section)

=== In rats ===
In addition to nonhuman primates, other animals are also shown metacognition. Foote and Crystal (2007) provided the first evidence that rats have the knowledge of what they know in a perceptual discrimination task.<ref>{{Cite journal|last1=Foote|first1=Allison L.|last2=Crystal|first2=Jonathon D.|date=March 2007|title=Metacognition in the Rat|journal=Current Biology|volume=17|issue=6|pages=551–555|doi=10.1016/j.cub.2007.01.061|pmid=17346969|issn=0960-9822|pmc=1861845|bibcode=2007CBio...17..551F }}</ref> Rats were required to classify brief noises as short or long. Some noises with intermediate durations were difficult to discriminate as short or long. Rats were provided with an option to decline to take the test on some trials but were forced to make responses on other trials. If they chose to take the test and respond correctly, they would receive a high reward but no reward if their classification of noises was incorrect. But if the rats decline to take the test, they would be guaranteed a smaller reward. The results showed that rats were more likely to decline to take the test when the difficulty of noise discrimination increased, suggesting rats knew they do not have the correct answers and declined to take the test to receive the reward. Another finding is that the performance was better when they had chosen to take the test compared with if the rats were forced to make responses, proving that some uncertain trials were declined to improve the accuracy.

These responses pattern might be attributed to actively monitor their own mental states. Alternatively, external cues such as environmental cue associations could be used to explain their behaviors in the discrimination task. Rats might have learned the association between intermediate stimuli and the decline option over time. Longer response latencies or some features inherent to stimuli can serve as discriminative cues to decline tests. Therefore, Templer, Lee, and Preston (2017) utilized an olfactory-based delayed match to sample (DMTS) memory task to assess whether rats were capable of metacognitive responding adaptively.<ref>{{Cite journal|last1=Templer|first1=Victoria L.|last2=Lee|first2=Keith A.|last3=Preston|first3=Aidan J.|date=2017-07-01|title=Rats know when they remember: transfer of metacognitive responding across odor-based delayed match-to-sample tests|url= |journal=Animal Cognition|volume=20|issue=5|pages=891–906|doi=10.1007/s10071-017-1109-3|pmid=28669115|issn=1435-9448|pmc=5709207}}</ref> Rats were exposed to sample odor first and chose to either decline or take the four-choice memory test after a delay. The correct choices of odor were associated with high reward and incorrect choices have no reward. The decline options were accompanied by a small reward.

In experiment 2, some “no-sample” trials were added in the memory test in which no odor was provided before the test. They hypothesized that rats would decline more often when there was no sample odor presented compared with odor presented if rats could internally assess the memory strength. Alternatively, if the decline option was motivated by external environmental cues, the rats would be less likely to decline the test because no available external cues were presented. The results showed that rats were more likely to decline the test in no-sample trials relative to normal sample trials, supporting the notion that rats can track their internal memory strength.

To rule out other potential possibilities, they also manipulated memory strength by providing the sampled odor twice and varying the retention interval between the learning and the test. Templer and colleagues (2017) found rats were less likely to decline the test if they had been exposed to the sample twice, suggesting that their memory strength for these samples was increased. Longer delayed sample test was more often declined than short delayed test because their memory was better after the short delay. Overall, their series of studies demonstrated that rats could distinguish between remembering and forgetting and rule out the possibilities that decline use was modulated by the external cues such as environmental cue associations.