Imitative Learning of Actions on Objects by Children, Chimpanzees, and Enculturated Chimpanzees

Abstract

In this study we compared the abilities of chimpanzees and human children to imitatively learn novel actions on objects. Of particular interest were possible differences between chimpanzees raised mostly with conspecifics (mother-reared) and chimpanzees raised in a human-like cultural environment (enculturated). Subjects were thus 3 enculturated and 3 mother-reared chimpanzees, along with 8 18-month-old and 8 30-month-old human children. Each subject was tested over a 2-day period with 16 novel objects. The introduction of each object was preceded by a baseline period in which the subject's natural proclivities toward the object were determined. For 12 objects, a human experimenter demonstrated first a simple and then a complex novel action, instructing the subject in each case to "Do what I do" (chimpanzees were prepared for the task behaviorally as well). For the other 4 objects, demonstration of a single action took place on the first day and the subject's opportunity to imitate was delayed until the second day, 48 hours later. Actions that a subject produced in baseline were excluded from further analysis. For each analyzed action, the subject's behavior was scored as to whether it successfully reproduced (1) the end result of the demonstrated action, and (2) the behavioral means used by the demonstrator. Results showed that in immediate imitation the mother-reared chimpanzees were much poorer imitators than the enculturated chimpanzees and the human children, who did not differ from one another. Surprisingly, on the delay trials, the enculturated chimpanzees significantly outperformed the other 3 groups. We conclude from these results that a human-like sociocultural environment is an essential component in the development of human-like social-cognitive and imitative learning skills for chimpanzees, and perhaps for human beings as well.

The Archaeology of Teaching and the Evolution ofHomo docens

“…The results show a notable increase with age in the ability to manage approximate imitation (Bjorklund and Bering 2003). However, mother-reared chimpanzees seem to do less well, while encultured apes can outperform human children on certain tasks (Tomasello, Savage-Rumbaugh, and Kruger 1993). Bjorklund and Bering (2003) suggest that part of what comprises the enculturation phenomenon is a greater conceptualization of human behavioral programs.…”

Social learning by imitation in a reptile (Pogona vitticeps)

“…Imitation 30 is thought to be cognitively complex because the observer not only has to acquire 31 information, but must also draw inferences about the behaviour observed, the constraints of 32 the situation, and the intentions or goals of the model. There is now evidence that non-human 33 species including apes (Tomasello et al 1993 we know nothing about these abilities of the third amniotic class -reptiles. 38…”

Spread of arbitrary conventions among chimpanzees: a controlled experiment

“…Whiten et al 1996;Hirata & Morimura 2000;Celli et al 2001;Whiten et al 2005;Horner et al 2006), experiments are also required to determine how habits, arbitrary conventions or signals develop and are learned within a group. Thus far, such experiments have included the transmission of conflict resolution (de Waal & Johanowicz 1993) as well as human-induced mimicking of arbitrary gestures, body movements and actions on objects (Tomasello et al 1993;Custance et al 1995;Myowa-Yamakoshi & Matsuzawa 1999;Call 2001;Bjorklund et al 2002). However, all of these studies have relied on cross-species interaction, making for limited relevance to conventions within primate communities.…”