Data from: A metacognitive illusion in monkeys

Like humans, monkeys can make accurate judgements about their own memory by reporting their confidence during cognitive tasks. Some have suggested that animals use associative learning to make accurate confidence judgements, while others have suggested animals directly access and estimate the strength of their memories. Here we test a third, non-exclusive possibility: perhaps monkeys, like humans, base metacognitive inferences on heuristic cues. Humans are known to use cues like perceptual fluency (e.g. how easy something is to see) when making metacognitive judgements. We tested monkeys using a match-to-sample task in which the perceptual fluency of the stimuli was manipulated. The monkeys made confidence wagers on their accuracy before or after each trial. We found that monkeys' wagers were affected by perceptual fluency even when their accuracy was not. This is novel evidence that animals are susceptible to metacognitive illusions similar to those experienced by humans.与人类相仿，猴子亦可在认知任务中通过报告自身信心水平，对自身记忆做出精准判断。部分研究者提出，动物可通过联想学习做出精准的信心判断；另有观点认为，动物能够直接调取并评估自身记忆的强度。本研究检验了第三种非排他性可能性：或许与人类一样，猴子的元认知推论（metacognitive inferences）也基于启发式线索（heuristic cues）。已知人类在开展元认知判断时，会借助诸如知觉流畅性（perceptual fluency，即视觉刺激的辨识难易程度）这类线索。我们采用匹配样本任务（match-to-sample task）对猴子进行实验，实验中对刺激物的知觉流畅性进行了操控。每一试次的前后，猴子均需针对自身判断的准确性做出信心投注。研究结果显示，即便猴子的判断准确性未受影响，其信心投注仍会受到知觉流畅性的调控。本研究首次提供证据表明，动物也会出现与人类相似的元认知错觉（metacognitive illusions）。