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Cultural variation in the use of overimitation by the Aka and Ngandu of the Congo Basin.

Berl RE, Hewlett BS - PLoS ONE (2015)

Bottom Line: Investigation of this feature in non-Western groups has found little difference cross-culturally in the frequency or manner with which individuals overimitate.Aka children were found not to overimitate as expected, instead displaying one of the lowest rates of overimitation seen under similar conditions.From these results, we conclude that cross-cultural variation exists in the use of overimitation during childhood.

View Article: PubMed Central - PubMed

Affiliation: School of Biological Sciences, Washington State University, Pullman, Washington, United States of America.

ABSTRACT
Studies in Western cultures have observed that both children and adults tend to overimitate, copying causally irrelevant actions in the presence of clear causal information. Investigation of this feature in non-Western groups has found little difference cross-culturally in the frequency or manner with which individuals overimitate. However, each of the non-Western populations studied thus far has a history of close interaction with Western cultures, such that they are now far removed from life in a hunter-gatherer or other small-scale culture. To investigate overimitation in a context of limited Western cultural influences, we conducted a study with the Aka hunter-gatherers and neighboring Ngandu horticulturalists of the Congo Basin rainforest in the southern Central African Republic. Aka children, Ngandu children, and Aka adults were presented with a reward retrieval task similar to those performed in previous studies, involving a demonstrated sequence of causally relevant and irrelevant actions. Aka children were found not to overimitate as expected, instead displaying one of the lowest rates of overimitation seen under similar conditions. Aka children copied fewer irrelevant actions than Aka adults, used a lower proportion of irrelevant actions than Ngandu children and Aka adults, and had less copying fidelity than Aka adults. Measures from Ngandu children were intermediate between the two Aka groups. Of the participants that succeeded in retrieving the reward, 60% of Aka children used emulation rather than imitation, compared to 15% of Ngandu children, 11% of Aka adults, and 0% of Western children of similar age. From these results, we conclude that cross-cultural variation exists in the use of overimitation during childhood. Further study is needed under a more diverse representation of cultural and socioeconomic groups in order to investigate the cognitive underpinnings of overimitation and its possible influences on social learning and the biological and cultural evolution of our species.

No MeSH data available.


Experimental apparatus and tool.Used for all participants and tests in this study. Relevant features include: (A) sliding top door; (B) transparent barrier (below the plane of the top side of the apparatus); (C) opaque reward chamber; (D) sliding/lifting front door; and (E) manipulating tool (shown to scale with apparatus). See Methods for details of construction and use.
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pone.0120180.g001: Experimental apparatus and tool.Used for all participants and tests in this study. Relevant features include: (A) sliding top door; (B) transparent barrier (below the plane of the top side of the apparatus); (C) opaque reward chamber; (D) sliding/lifting front door; and (E) manipulating tool (shown to scale with apparatus). See Methods for details of construction and use.

Mentions: The study apparatus was a transparent polycarbonate box (see Fig. 1), measuring roughly 15 cm x 15 cm x 15 cm and similar to those used by Horner and Whiten [21], McGuigan et al. [26], McGuigan and Whiten [22], and McGuigan et al. [28], differing only in the top door mechanism. Two holes (each 2 cm x 2 cm) allowed entry into the box, one on the top side and one on the front side. The front hole was covered by a door with a small knob and allowed entry by sliding the door to either side or by lifting it upward and outward. The top hole was covered by a sliding door with an open notch and could be slid only to the left. A 22-cm-long aluminum tool with two short knobs protruding from one end and a long flat section on the opposite end was used to interact with the box and retrieve the reward—a small piece of bubble gum—which was stored in an opaque black rectangular prism connected to the inside of the front hole. The top hole led to a chamber with a transparent barrier separating it from the rest of the box and the reward. Thus, demonstrated actions performed on the top or sides of the box were causally irrelevant to obtaining the reward. Opening the front door and obtaining the reward were judged to be causally relevant.


Cultural variation in the use of overimitation by the Aka and Ngandu of the Congo Basin.

Berl RE, Hewlett BS - PLoS ONE (2015)

Experimental apparatus and tool.Used for all participants and tests in this study. Relevant features include: (A) sliding top door; (B) transparent barrier (below the plane of the top side of the apparatus); (C) opaque reward chamber; (D) sliding/lifting front door; and (E) manipulating tool (shown to scale with apparatus). See Methods for details of construction and use.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4376636&req=5

pone.0120180.g001: Experimental apparatus and tool.Used for all participants and tests in this study. Relevant features include: (A) sliding top door; (B) transparent barrier (below the plane of the top side of the apparatus); (C) opaque reward chamber; (D) sliding/lifting front door; and (E) manipulating tool (shown to scale with apparatus). See Methods for details of construction and use.
Mentions: The study apparatus was a transparent polycarbonate box (see Fig. 1), measuring roughly 15 cm x 15 cm x 15 cm and similar to those used by Horner and Whiten [21], McGuigan et al. [26], McGuigan and Whiten [22], and McGuigan et al. [28], differing only in the top door mechanism. Two holes (each 2 cm x 2 cm) allowed entry into the box, one on the top side and one on the front side. The front hole was covered by a door with a small knob and allowed entry by sliding the door to either side or by lifting it upward and outward. The top hole was covered by a sliding door with an open notch and could be slid only to the left. A 22-cm-long aluminum tool with two short knobs protruding from one end and a long flat section on the opposite end was used to interact with the box and retrieve the reward—a small piece of bubble gum—which was stored in an opaque black rectangular prism connected to the inside of the front hole. The top hole led to a chamber with a transparent barrier separating it from the rest of the box and the reward. Thus, demonstrated actions performed on the top or sides of the box were causally irrelevant to obtaining the reward. Opening the front door and obtaining the reward were judged to be causally relevant.

Bottom Line: Investigation of this feature in non-Western groups has found little difference cross-culturally in the frequency or manner with which individuals overimitate.Aka children were found not to overimitate as expected, instead displaying one of the lowest rates of overimitation seen under similar conditions.From these results, we conclude that cross-cultural variation exists in the use of overimitation during childhood.

View Article: PubMed Central - PubMed

Affiliation: School of Biological Sciences, Washington State University, Pullman, Washington, United States of America.

ABSTRACT
Studies in Western cultures have observed that both children and adults tend to overimitate, copying causally irrelevant actions in the presence of clear causal information. Investigation of this feature in non-Western groups has found little difference cross-culturally in the frequency or manner with which individuals overimitate. However, each of the non-Western populations studied thus far has a history of close interaction with Western cultures, such that they are now far removed from life in a hunter-gatherer or other small-scale culture. To investigate overimitation in a context of limited Western cultural influences, we conducted a study with the Aka hunter-gatherers and neighboring Ngandu horticulturalists of the Congo Basin rainforest in the southern Central African Republic. Aka children, Ngandu children, and Aka adults were presented with a reward retrieval task similar to those performed in previous studies, involving a demonstrated sequence of causally relevant and irrelevant actions. Aka children were found not to overimitate as expected, instead displaying one of the lowest rates of overimitation seen under similar conditions. Aka children copied fewer irrelevant actions than Aka adults, used a lower proportion of irrelevant actions than Ngandu children and Aka adults, and had less copying fidelity than Aka adults. Measures from Ngandu children were intermediate between the two Aka groups. Of the participants that succeeded in retrieving the reward, 60% of Aka children used emulation rather than imitation, compared to 15% of Ngandu children, 11% of Aka adults, and 0% of Western children of similar age. From these results, we conclude that cross-cultural variation exists in the use of overimitation during childhood. Further study is needed under a more diverse representation of cultural and socioeconomic groups in order to investigate the cognitive underpinnings of overimitation and its possible influences on social learning and the biological and cultural evolution of our species.

No MeSH data available.