Department of Psychology, Research Center in Psychology of Cognition, Language and Emotion, Aix-Marseille University, 13621 Aix-en-Provence, France.
Am J Phys Anthropol. 2010 Apr;141(4):638-45. doi: 10.1002/ajpa.21244.
Predominance of right-handedness has historically been considered as a hallmark of human evolution. Whether nonhuman primates exhibit population-level manual bias remains a controversial topic. Here, we investigated the hypothesis that bimanual coordinated activities may be a key-behavior in our ancestors for the emergence and evolution of human population-level right-handedness. To this end, we collected data on hand preferences in 35 captive gorillas (Gorilla gorilla) during simple unimanual reaching and for bimanual coordinated feeding. Unimanual reaching consisted of grasping food on the ground, while bimanual feeding consisted of using one hand for holding a food and processing the food item by the opposite hand. No population-level manual bias was found for unimanual actions but, in contrast, gorillas exhibited a significant population-level right-handedness for the bimanual actions. Moreover, the degree of right-handedness for bimanual feeding exceeds any other known reports of hand use in primates, suggesting that lateralization for bimanual feeding is robust in captive gorillas. The collective evidence is discussed in the context of potential continuity of handedness between human and nonhuman primates.
惯用右手在历史上一直被认为是人类进化的标志。非人类灵长类动物是否表现出群体水平的手性偏向仍然是一个有争议的话题。在这里，我们研究了这样一个假设，即双手协调活动可能是我们祖先在出现和进化为人类群体惯用右手的关键行为。为此，我们在 35 只圈养大猩猩（Gorilla gorilla）中收集了关于单手和双手协调进食时手偏好的数据。单手动作包括在地面上抓取食物，而双手协调进食则包括用一只手握住食物并用另一只手处理食物。对于单手动作没有发现群体水平的手性偏向，但相比之下，大猩猩在双手协调动作中表现出明显的群体水平的右利手。此外，双手协调进食的右利手程度超过了灵长类动物中任何其他已知的手部使用报告，这表明在圈养大猩猩中，双手协调进食的偏侧性是强大的。在讨论人类和非人类灵长类动物之间手性连续性的潜在问题时，我们考虑了这些综合证据。
