Synchronized practice helps bearded capuchin monkeys learn to extend attention while learning a tradition

Abstract

Culture extends biology in that the setting of development shapes the traditions that individuals learn, and over time, traditions evolve as occasional variations are learned by others. In humans, interactions with others impact the development of cognitive processes, such as sustained attention, that shape how individuals learn as well as what they learn. Thus, learning itself is impacted by culture. Here, we explore how social partners might shape the development of psychological processes impacting learning a tradition. We studied bearded capuchin monkeys learning a traditional tool-using skill, cracking nuts using stone hammers. Young monkeys practice components of cracking nuts with stones for years before achieving proficiency. We examined the time course of young monkeys' activity with nuts before, during, and following others' cracking nuts. Results demonstrate that the onset of others' cracking nuts immediately prompts young monkeys to start handling and percussing nuts, and they continue these activities while others are cracking. When others stop cracking nuts, young monkeys sustain the uncommon actions of percussing and striking nuts for shorter periods than the more common actions of handling nuts. We conclude that nut-cracking by adults can promote the development of sustained attention for the critical but less common actions that young monkeys must practice to learn this traditional skill. This work suggests that in nonhuman species, as in humans, socially specified settings of development impact learning processes as well as learning outcomes. Nonhumans, like humans, may be culturally variable learners.T raditions are behaviors shared among members of a group that are reliably learned by new individuals, in part, with social support (1). The concept of tradition highlights behavioral consistency over time and across individuals. Here, we emphasize the origin of traditions in learning. Learned behavior is one manifestation of developmental plasticity, and generation of novel behavior is another. Novel behavioral variants may be learned by others, thus modifying existing traditions or leading to new ones (2). In this way, developmental plasticity enables heritable modification of behavior through learning, with the result that culture may extend biology (3, 4). Traditions appear to be widespread in the animal kingdom (5-7), leading theorists to propose that cultural evolution, rather than being restricted to recent human history, has general evolutionary significance (8, 9). Apes (6, 10) and monkeys provide several examples of traditions. Among monkeys, for example, vervet monkeys learn their mothers' food-processing techniques (11) and white-faced capuchin monkeys learn odd social games, such as poking a finger in another monkey's eye, that become established intermittently in groups (2, 12).Given the essential role of learning in traditions, cognitive processes associated with learning that show developmental plasticity themselves, should be incorporated into our understanding of how culture can...

Culture extends the scope of evolutionary biology in the great apes

“…Other convergences span different ape genera, such as use of fly swats and leaf napkins by both chimpanzees and orangutans; again, these behaviors are neither species instincts nor individually learned, because they are habitual at some locations but are absent in the same species at other locations. Finally there are convergences between apes and other primates, e.g., the use of stones as hammers to break open hard-cased food by distantly related long-tailed macaques (92) and capuchins (3,93).…”

“…This article focuses on great apes: chimpanzee (Pan troglodytes), gorilla (Gorilla gorilla), and orangutan (Pongo pygmaeus). Other primates are dealt with elsewhere in the issue (3,4). Despite an early report (5), we still know little about cultural phenomena in chimpanzees' rarer sister species, the bonobo (Pan paniscus) so bonobos are omitted here.…”

The extension of biology through culture

“…Hundreds of laboratory experimental studies have demonstrated social learning and transmission in a wide variety of animals. Social learning is now extensively documented in mammals (29), with a particular intensity of research studies in primates (30)(31)(32)(33) and cetaceans (34)(35)(36)(37), in birds (38)(39)(40)(41), in fish (42), and in insects (43,44). The fact that social learning has been shown to play important roles spanning multiple functional contexts (25)(26)(27)(28) suggests that many animals are not simply acquiring one or a few behavioral patterns socially, but rather that social learning is central to their acquisition of adaptive behavior.…”

“…As in the capuchin study of Fragaszy et al (32), the psychological and social processes that allow human culture to be so distinctive need to be examined as individuals' life histories unfold, and the affordances of the culture in which they develop are selectively assimilated and further modified. On the one hand, these processes are part of our species' biology, their properties shaped during the millennia of evolutionary time over which our ancestors became increasingly and intensively dependent on cumulative cultural inheritance (54,56,57).…”

“…Here, this is illustrated in analyses of extended ontogeny of difficult skills, like nut-cracking in primates (32,48). Moreover, even innovations, the analog of mutations that become subject to selective adoption and further transmission to others, may be far from random; instead, they are often immediately functional, most clearly in the example of intelligent, goal-oriented human inventions, but also in the closest animal counterparts.…”