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ERIC Number: EJ849136
Record Type: Journal
Publication Date: 2007-May
Pages: 11
Abstractor: As Provided
Reference Count: 64
ISSN: ISSN-1363-755X
Gravity Bias in Young and Adult Chimpanzees ("Pan Troglodytes"): Tests with a Modified Opaque-Tubes Task
Tomonaga, Masaki; Imura, Tomoko; Mizuno, Yuu; Tanaka, Masayuki
Developmental Science, v10 n3 p411-421 May 2007
Young human children at around 2 years of age fail to predict the correct location of an object when it is dropped from the top of an S-shape opaque tube. They search in the location just below the releasing point (Hood, 1995). This type of error, called a "gravity bias", has recently been reported in dogs and monkeys. In the present study, we investigated whether young and adult chimpanzees also show such a gravity bias in a modified version of the original opaque-tube task. The original task by Hood and colleagues required the subject to search in a location after the object had fallen, while in the task reported here, subjects were required to predict the location before the object was dropped. Thus the present procedure does not involve explicit invisible displacement operations, one of the important components of the original procedure. In Experiment 1 both young (1.5-2.5-year-old) and adult chimpanzees predicted the location of falling food items below the releasing point even when crossed tubes were used. These gravity errors remained after the extensive experience of using the tubes themselves. Experiment 2 further tested adult and 4-year-old chimpanzees under the set-up in which the straight and crossed tubes were simultaneously presented. The results were the same as those in the previous test, suggesting that developmental changes and learning effect do not affect the gravity bias in chimpanzees.
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Publication Type: Journal Articles; Reports - Evaluative
Education Level: N/A
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A