To test for evidence of metacognition in capuchin monkeys (Sapajus apella), we analyzed confidence movements using a paradigm adapted from research with chimpanzees. Capuchin monkeys provide an interesting model species for the comparative assessment of metacognition as they show limited evidence of such cognitive-monitoring processes in a variety of metacognition paradigms. Here, monkeys were presented with a computerized delayed matching-to-sample (DMTS) memory test in one location but were rewarded for correct responses in a separate location. Movements could be made from one location to the other at any time, but movements between a response and reward feedback may reflect confidence in the accuracy of the response. Critically, DMTS tests included occasional "no sample" trials where monkeys' performance was at chance when the trial started without a sample and a 1-s interval to the response options. We predicted that monkeys would (1) perform less accurately (and less confidently) at longer retention intervals, (2) move to the dispenser early more often on trials completed correctly than incorrectly, and (3) show a relation between faster response latency and early movements. Analyses of response times and "go" or "no go" confidence movements before feedback to the reward location suggested that the monkeys were capable of monitoring confidence in their responses. However, their confidence movements were less precise and less flexible than chimpanzees. Overall, this paradigm can reveal potential metacognitive abilities in nonhuman animals that otherwise demonstrate these abilities inconsistently.

中文翻译：

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卷尾猴（有时）知道时会走：Sapajus apella中的自信心运动。

为了测试卷尾猴（Sapajus apella）中元认知的证据，我们使用了根据对黑猩猩进行研究而改编的范例分析了置信度运动。卷尾猴为元认知的比较评估提供了一个有趣的模型物种，因为它们在各种元认知范例中显示出这种认知监控过程的有限证据。在这里，猴子在一个位置接受了计算机延迟的样本匹配匹配（DMTS）记忆测试，但在单独的位置因正确的反应而受到奖励。可以随时从一个位置移动到另一位置，但是响应和奖励反馈之间的移动可能反映出对响应准确性的信心。至关重要的是，DMTS测试包括偶尔的“无样本”测试，其中猴子会 当试验开始时没有样本且响应选项的间隔为1-s时，性能是偶然的。我们预测，猴子（1）在较长的保留时间间隔内表现会较不准确（并且信心较差），（2）在正确完成的实验中比不正确地更早地移至分配器，并且（3）显示更快的响应潜伏期与早期动作。在反馈到奖励位置之前，分析响应时间以及“执行”或“不执行”的置信度，这表明猴子能够监测其响应的置信度。但是，与黑猩猩相比，他们的自信心运动不够精确，也缺乏灵活性。总的来说，这种范例可以揭示非人类动物潜在的元认知能力，否则它们将不一致地证明这些能力。