Comparison between long-tailed macaques and humans, the strength of task specialization in relation to task complexity.

• Main Author: Goh, Colleen.
• Other Authors: Michael David Gumert
• Format: Final Year Project
• Language: English
• Published: 2011
• Subjects: DRNTU::Science
• Online Access: http://hdl.handle.net/10356/46441
• Institution: Nanyang Technological University

This study examined how the strength of lateralization varied with task complexity for humans and long-tailed macaques (Macaca fascicularis). By measuring the same spectrum of tasks (varying in complexity) for both species, we compared how strength of lateralization varied between each task and whether it differed between the two species. The four tasks studied were “putting object into mouth”, “grabbing juvenile/ infant”, “manipulation of object” and “grooming/ adjusting hair” (from lowest level of complexity to highest). The strength of lateralization was significantly stronger in the humans than in the macaques for more complex tasks. 14 out of 33 of the macaques showed individual-level handedness, of which 7 were biased to the right and 7 to the left, much lesser than the 24 out of 32 of the humans that showed individual-level handedness. These findings could be attributed to the higher degree of hemispheric specialization which exists in humans as compared to the macaques. Finally, for both species, the strength of lateralization did not increase with the increase in complexity of task here. A reassessment in the level of complexity tasks measured and more specific studies on complex tasks are probably required to elicit the increase in strength of lateralization with task complexity.