Great apes selectively retrieve relevant memories to guide action

Abstract

Memory allows us to draw on past experiences to inform behaviour in the present. However, memories rarely match the situation at hand exactly, and new situations regularly trigger multiple related memories where only some are relevant to act upon. The flexibility of human memory systems is largely attributed to the ability to disregard irrelevant, but salient, memories in favour of relevant ones. This is considered an expression of an executive function responsible for suppressing irrelevant memories, associated with the prefrontal cortex. It is unclear to what extent animals have access to this ability. Here, we demonstrate, in a series of tool-use tasks designed to evoke conflicting memories, that chimpanzees and an orangutan suffer from this conflict but overcome it in favour of a more relevant memory. Such mnemonic flexibility is among the most advanced expressions of executive function shown in animals to date and might explain several behaviours related to tool-use, innovation, planning and more.

Goffin's Cockatoos (Cacatua goffiniana) Can Solve a Novel Problem After Conflicting Past Experiences

“…Instead, we focus on interactions between tools and features of the test apparatus because these interactions indicate which associations are currently applied by the bird to the task at hand. This was also the case in the study with great apes (Bobrowicz et al, 2020).…”

“…A recent study on an orangutan and chimpanzees suggests that great apes flexibly use relevant experiences to solve a novel problem, even if interrupted by irrelevant experiences (Bobrowicz et al, 2020 ). Across two experimental conditions, great apes generalized tool function despite irrelevant perceptually-based relations that were either distracting (no-conflict condition) or misleading (conflict condition).…”

“…As generalizations always happen in response to a present problem, they must draw on flexible memory retrieval. For instance, in the test task presented to the great apes (Bobrowicz et al, 2020 ), they needed to match the perceptual cues in the task with perceptual cues encoded in the past task(s) and retrieve the relation(s) that back then led to a successful solution. Such generalizations result from re-combinations of memory traces whose retrieval is triggered by currently available cues.…”

“…They also solve novel problems by recombining familiar ones and are sensitive to both functionally relevant and irrelevant aspects of such problems (Auersperg et al, 2013a ). Notably, they can innovate several modes of tool use [10, 16], which is important from a comparative perspective as ape memory flexibility was tested in a tool-using context (Bobrowicz et al, 2020 ). Therefore, Goffins are ideal non-hominoid candidates to investigate memory flexibility.…”

The evolution of episodic-like memory: the importance of biological and ecological constraints

“…A related, interesting case is the chimpanzee Panzee, who could indicate the place where food was hidden outside her enclosure(Menzel 2005; see alsoBobrowicz, Johansson & Osvath 2020).…”