Self-control in crows, parrots and nonhuman primates

Abstract

Self-control is critical for both humans and nonhuman animals because it underlies complex cognitive abilities, such as decision-making and future planning, enabling goal-directed behavior. For instance, it is positively associated with social competence and life success measures in humans. We present the first review of delay of gratification as a measure of self-control in nonhuman primates, corvids (crow family) and psittacines (parrot order): disparate groups that show comparable advanced cognitive abilities and similar socio-ecological factors. We compare delay of gratification performance and identify key issues and outstanding areas for future research, including finding the best measures and drivers of delayed gratification. Our review therefore contributes to our understanding of both delayed gratification as a measure of self-control and of complex cognition in animals. This article is categorized under: Cognitive Biology > Evolutionary Roots of Cognition Psychology > Comparative Psychology.

Keywords: comparative cognition; corvids; delayed gratification; parrots; self-control.

Figure 1

Schematic representation of a phylogenetic tree showing taxa included within this review, in order to show relative distance of relatedness. Roughly 296 million years ago (mya), birds and mammals diverged. Parrots and corvids diverged roughly 96.4 mya. New world monkeys diverged 35 mya, old world monkeys 25 mya, and great apes between 12 and 6 mya from human evolution

Figure 2

Maximum tolerated length of delays (by any individual) in exchange tasks when rewards differ in either quality (black) or quantity (white) (references in Table 1). Note that, unlike the other studies, in the African gray parrot study, the subject had been trained to respond to a “wait” command and was verbally instructed to wait in the test—other gray parrots were unable to wait more than a few seconds (Vick et al., 2010)

Figure 3

Percentage of successful trials in exchange tasks with a 2‐s delay when rewards differ in either quality (black) or quantity (white). Species selected reflects those studies where this data was published or made available from the original study authors (Auersperg et al., 2013; Dufour et al., 2007; Dufour et al., 2012; Hillemann et al., 2014)