Self-control in the monkeymacaca fascicularis

Abstract

Two experiments tested two cynomolgus monkeys' self-control-choice of a longer, more delayed reinforcer over a shorter, less delayed reinforcer. In Experiment 1, subjects exhibited significant selfcontrol in a procedure in which reinforcer amounts and delays were held constant throughout a condition. In Experiment 2, subjects exhibited significantly greater sensitivity to variation in reinforcer amount than to variation in reinforcer delay in a procedure in which the reinforcer delay associated with the self-control alternative was adjusted until each macaque was indifferent between the two alternatives. Both experiments indicated that, in laboratory paradigms in which humans show self-control and pigeons and rats show impulsiveness, macaques show self-control. These results are inconsistent with the hypothesis that species differences in self-control are a function of language ability or of specific types of prior training. The results are consistent with the hypothesis that species differences in self-control are related to the ratio of brain size to body weight (a possible indicator of general cognitive ability) or to shared phylogeny.

Intertemporal choice in lemurs

“…The observed mean adjusted delays ranged from 9-25 s. Relative to other species tested Seven species have been tested using the same adjusting-delay procedure with two versus six food items: lemurs (this study), cotton-top tamarins and common marmosets (Stevens et al, 2005a), brown capuchins (Addessi et al, 2011), long-tailed macaques (Tobin et al, 1996), and bonobos and chimpanzees (Rosati et al, 2007). The mean adjusted delay at indifference for lemurs matched that found in common marmosets.…”

“…For these species, the subjects chose between two food items available immediately and six food items after an adjusting delay. In addition to the lemurs, this included cotton-top tamarins (Saguinus oedipus) and common marmosets (Callithrix jacchus, Stevens et al, 2005a), long-tailed macaques (Macaca fascicularis, Tobin et al, 1996), brown capuchins (Cebus apella, Addessi et al, 2011), and bonobos (Pan paniscus) and chimpanzees (Pan troglodytes, Rosati et al, 2007). In addition, seven species were tested with slightly different methodologies.…”

“…Historically, most experimental studies of intertemporal choices in animals tested primarily pigeons and rats (McDiarmid and Rilling, 1965;Richards et al, 1997). More recently, however, researchers have tested many more species, including insects, fish, birds, mice, and primates (Bateson and Kacelnik, 1996;Tobin et al, 1996;Brunner and Hen, 1997;Cheng et al, 2002;Stevens et al, 2005a;Rosati et al, 2007;Pearson et al, 2010;Vick et al, 2010;Mühlhoff et al, 2011).…”

“…Tobin et al (1996), Stevens et al (2005a), Rosati et al (2007), and Addessi et al (2011) have used the same adjusting-delay 'self-control' paradigm to test intertemporal choices in Old World monkeys, New World monkeys, and apes. In this task, subjects make binary choices between two immediately available food items and six food items available after a time delay.…”

A socioecological perspective on primate cognition, past and present

“…Monkeys seem to have more self control than pigeons or rats (Tobin and Logue 1994;Tobin et al 1996). Experiments with tamarins and marmosets (Stevens et al 2005a, b) suggest the feeding ecology of these monkeys shaped the evolution of self control in those taxa.…”