Recent experiments with rats suggest that they show episodic-like or what-where-when memory for a preferred food found on a radial maze. Although memory for when a salient event occurred suggests that rats can mentally travel in time to a moment in the past, an alternative possibility is that they remember how long ago the food was found. Three groups of rats were tested for memory of previously encountered food. The different groups could use only the cues of when, how long ago, or when + how long ago. Only the cue of how long ago food was encountered was used successfully. These results suggest that episodic-like memory in rats is qualitatively different from human episodic memory.

In 4 experiments, the authors asked whether pigeons (Columba livia) would show metamemory by choosing to study a sample stimulus before taking a memory test. In Experiments 1a-1c, pigeons chose between cues that led either to exposure to a sample stimulus or directly to the comparison test stimuli without seeing the sample in a delayed matching-to-sample task. The same choice was used in Experiment 2 to see whether pigeons would take a reminder when memory of the sample was weak. In Experiments 3 and 4, pigeons' responses led to either a choice between red and green side keys with a sample present to guide the choice or a choice with no sample present. The findings of all of these experiments suggest the absence of metamemory in pigeons.

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Metacognition refers to humans' ability to monitor the state of their own learning and to judge the correctness of information retrieved from memory. Inferences about metacognition-like processes in non-human animals have been made from studies in which subjects judge the adequacy of previously presented information and from information seeking studies in which no prior knowledge exists. This article briefly reviews the former type of experiments but focuses on studies of information seeking. A number of studies now indicate that apes and monkeys will look down opaque tubes or under opaque containers to see the location of a hidden reward. They less often make looking responses when other information indicates the location of reward, such as visible baiting, transparent tubes or containers, or logical inference. Studies of information seeking in pigeons, rats, and dogs are reported that indicate they do not readily show the types of looking responses seen in primates. If given a forced choice between stimuli that do and do not yield information about the location of reward, however, these non-primates make the informative choice. It is suggested that the choice of information in these pigeon, rat, and dog experiments may be a form of secondary sign-tracking and thus different from the metacognition-like processes used by primates.