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Behavioral Assessment of Manual Dexterity in Non-Human Primates
Published on: November 11, 2011
Bipedal tool use strengthens chimpanzee hand preferences
Stephanie Braccini1, Susan Lambeth, Steve Schapiro
1Centre for Social Learning and Cognitive Evolution, School of Psychology, University of St Andrews, St Andrews, United Kingdom.
Journal of Human Evolution
|January 22, 2010
Summary
Bipedal tool use in chimpanzees emphasizes existing hand preferences, increasing lateralization but not favoring a specific hand. This suggests postural demands amplify subtle biases, impacting theories on human evolution.
Area of Science:
- Primate behavior
- Evolutionary biology
- Neuroscience
Background:
- Primate behavioral lateralization, particularly hand preference, is debated.
- Understanding lateralization in non-human primates offers insights into human evolution.
Purpose of the Study:
- Investigate the link between hand preference and posture during tool use in chimpanzees.
- Test if bipedal posture strengthens hand preference and if bipedalism elicits right-handedness.
Main Methods:
- Experimentally induced tool use in chimpanzees across supported bipedal, unsupported bipedal, and seated postures.
- Assessed hand preference and posture during tool manipulation.
Main Results:
- Bipedal posture significantly increased the strength of hand preference in chimpanzees.
- Bipedalism did not consistently elicit a right-hand preference; instead, it amplified pre-existing biases.
- Unsupported bipedal tool use highlighted individual lateralization differences.
Conclusions:
- Postural demands, like bipedalism, can enhance behavioral lateralization in primates.
- The combination of bipedalism and tool use may have contributed to human lateralization, but doesn't solely explain right-handedness.
