What’s Special about Human Imitation? A Comparison with Enculturated Apes

Abstract

What, if anything, is special about human imitation? An evaluation of enculturated apes’ imitation skills, a “best case scenario” of non-human apes’ imitation performance, reveals important similarities and differences between this special population of apes and human children. Candidates for shared imitation mechanisms include the ability to imitate various familiar transitive responses and object–object actions that involve familiar tools. Candidates for uniquely derived imitation mechanisms include: imitating novel transitive actions and novel tool-using responses as well as imitating opaque or intransitive gestures, regardless of familiarity. While the evidence demonstrates that enculturated apes outperform non-enculturated apes and perform more like human children, all apes, regardless of rearing history, generally excel at imitating familiar, over-rehearsed responses and are poor, relative to human children, at imitating novel, opaque or intransitive responses. Given the similarities between the sensory and motor systems of preschool age human children and non-human apes, it is unlikely that differences in sensory input and/or motor-output alone explain the observed discontinuities in imitation performance. The special rearing history of enculturated apes—including imitation-specific training—further diminishes arguments suggesting that differences are experience-dependent. Here, it is argued that such differences are best explained by distinct, specialized mechanisms that have evolved for copying rules and responses in particular content domains. Uniquely derived social and imitation learning mechanisms may represent adaptations for learning novel communicative gestures and complex tool-use. Given our species’ dependence on both language and tools, mechanisms that accelerated learning in these domains are likely to have faced intense selective pressures, starting with the earliest of human ancestors.

Advances in Animal Cognition

“…Consistent with Subiual’s [8] conclusion, researchers have advanced the idea that humans alone may be capable of representing concepts for constructs that are abstract and unobservable [14]. Reasoning about causal forces may be considered one class of constructs about unobservables.…”

“…For example, Subiaul [8] has developed a model of imitation that consists of multiple forms of imitation, e.g., imitation for familiar and unfamiliar actions, and imitation of opaque or intransitive gestures. Subiaul’s model is consistent with the idea that individuals, or species, may have the ability for certain kinds of imitation, but not others.…”

“…Acknowledging that cognitive abilities may be parsed into separate modules allows for a better basis of comparison between species. Subiaul [8] indicates that human children alone may be capable of imitating novel transitive actions and intransitive actions, while other apes may share the capacity to imitate familiar transitive actions. Rejection of the all-or-none approach to studying species’ differences in cognition represents an advance in understanding which mechanisms may be shared widely in the animal kingdom, and which might be more specialized.…”

“…Perdue’s study [6] represents one example of an effective working collaboration between a zoo and an academic investigator. Subiaul’s work [8] with human children and great apes also takes place in a zoological setting, which allows for both the recruitment of participants and the immediate dissemination of the results of these studies. Researchers will have to become more resourceful in obtaining subjects to participate in their research protocols.…”

“…This Special Issue presents a series of papers that embody the innovation and breadth embraced by scientists currently investigating animal cognition. Papers are presented on species ranging from bumblebees [2], to North Island robins [3], Jamaican fruit bats [4], domestic horses [5], sun bears [6], and non-human primates [7,8,9,10,11]. The research reported in this issue was conducted in a range of wild and captive environments, including laboratories, zoos, and conservation organizations.…”