Chimpanzees (Pan troglodytes) show subtle signs of uncertainty when choices are more difficult

Matthias Allritz,Emma Suvi Mcewen,Josep Call

doi:10.1016/j.cognition.2021.104766

Abstract

Humans can tell when they find a task difficult. Subtle uncertainty behaviors like changes in motor speed and muscle tension precede and affect these experiences. Theories of animal metacognition likewise stress the importance of endogenous signals of uncertainty as cues that motivate metacognitive behaviors. However, while researchers have investigated second-order behaviors like information seeking and declining difficult trials in nonhuman animals, they have devoted little attention to the behaviors that express the cognitive conflict that gives rise to such behaviors in the first place. Here we explored whether three chimpanzees would, like humans, show hand wavering more when faced with more difficult choices in a touch screen transitive inference task. While accuracy was very high across all conditions, all chimpanzees wavered more frequently in trials that were objectively more difficult, demonstrating a signature behavior which accompanies experiences of difficulty in humans. This lends plausibility to the idea that feelings of uncertainty, like other emotions, can be studied in nonhuman animals. We propose to routinely assess uncertainty behaviors to inform models of procedural metacognition in nonhuman animals.

Highlights

Humans can tell when they find a task difficult
The first is theoretical: because for humans, uncertainty behaviors are correlated with objective task difficulty and subjective experiences of difficulty (Dotan et al, 2018; Questienne et al, 2018; Wokke et al, 2020), our finding provides indirect support for the hypothesis that chimpanzees subjectively experience feelings of uncertainty in similar ways
We presented three chimpanzees with a transitive inference task that probed their responses to pairs of images from a learned list

Summary

Introduction

Humans can tell when they find a task difficult. Faced with a tough multiple-choice problem, we may catch ourselves as we are about to make a mistake, or we may notice that we are going back and forth between choices. Philosophers have often mentioned that when humans report such feelings, this is accompanied by characteristic behaviors, e.g. wavering between options, hesitating, or frowning (Carruthers, 2017; Dokic, 2012; Proust, 2012). This is consistent with the finding that explicit metacognitive ap praisals As in previous studies, experiencing a feeling of almost having made an error was correlated with response time This relationship was stronger when the response was preceded by a subtle EMG response from the incorrect hand than when it was not, implying that the metacognitive appraisal was sensitive to the experience of motor response competition. Subtle changes in finger speed and acceleration suggested that online

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Conclusion