O'malley Robert C, McGrew W C
Department of Anthropology, University of Southern California, Los Angeles, CA 90089, USA.
Primates. 2006 Jul;47(3):279-83. doi: 10.1007/s10329-006-0180-1. Epub 2006 Apr 8.
The strength of the evidence for population-level handedness in the great apes is a topic of considerable debate, yet there have been few studies of handedness in orangutans. We conducted a study of manual lateralization in a captive group of eight orangutans (Pongo pygmaeus) ranking the degrees of manual preference according to a defined framework. We analyzed five behavioral patterns: eat (one- and two-handed), make/modify tool, oral tool-use, and manual tool-use. Although some individuals showed significant manual preferences for one or more tasks, at the group-level both one-handed and two-handed eating, oral tool-use, and make/modify tool were ranked at level 1 (unlateralized). Manual tool-use was ranked at level 2, with four subjects demonstrating significant hand preferences, but no group-level bias to the right or left. Four subjects also showed hand specialization to the right or left across several tasks. These results are consistent with most previous studies of manual preference in orangutans. The emergence of manual lateralization in orangutans may relate to more complex manipulative tasks. We hypothesize that more challenging manual tasks elicit stronger hand preferences.
关于大型猿类群体水平上利手情况的证据力度是一个备受争议的话题，然而对红毛猩猩利手情况的研究却很少。我们对一组圈养的八只红毛猩猩（婆罗洲猩猩）进行了一项关于用手偏侧性的研究，根据一个既定框架对用手偏好程度进行排名。我们分析了五种行为模式：进食（单手和双手）、制作/修改工具、口腔工具使用和手动工具使用。尽管一些个体在一项或多项任务中表现出明显的用手偏好，但在群体水平上，单手和双手进食、口腔工具使用以及制作/修改工具都被列为第1级（无偏侧化）。手动工具使用被列为第2级，有四名受试者表现出明显的用手偏好，但在群体水平上没有左右偏向。四名受试者在多项任务中也表现出右手或左手的专门化。这些结果与之前大多数关于红毛猩猩用手偏好的研究一致。红毛猩猩用手偏侧化的出现可能与更复杂的操作任务有关。我们假设更具挑战性的手动任务会引发更强的用手偏好。
