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

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.

Primate origins of corepresentation and cooperative flexibility: A comparative study with common marmosets (Callithrix jacchus), brown capuchins (Sapajus apella), and Tonkean macaques (Macaca tonkeana).

“…The number of changes in the heading direction indicating hesitation in the decision-making process (see Allritz et al, 2021, for hand wavering in chimpanzees in a touch screen task as a sign of subtle uncertainty behavior) described how many times the focal individual changed the direction toward which it was oriented or moving before grasping one of the handles.…”

Chimpanzees ( Pan troglodytes ) navigate to find hidden fruit in a virtual environment

“…These results will be further discussed below. In addition to the finding that most chimpanzees solved most of the navigation challenges that we gave them, it stands out that they did so rather quickly when compared with the extensive training times associated with some types of touch screen tasks that use static stimuli, which may require months of training with thousands of trials for nonhuman primates, e.g., color discrimination (69), transitive inference (70), and relational matching (71). The current finding of rapid adjustment to a navigation problem is consistent with results from other computer-presented spatial tasks (46,48).…”

Social cognition and metacognition in great apes: a theory

“…The investigators note that, unlike the opt-out task, this is a spontaneous measure that is not connected to rewards, and therefore, explanations in terms of associative learning and reward contingencies are not applicable. Allritz et al ( 2021 ) strengthened this finding by observing that when chimpanzees were presented with difficult (versus easy) problems on a touchscreen, their hand more often hovered over the screen as a natural and endogenous expression of their uncertainty. From the other direction, Beran et al ( 2015 ) gave chimpanzees a discrimination task for which they would be rewarded for correct performance, but from a reward dispenser that was some meters away with the reward only briefly available.…”