Fletcher Alison W, Weghorst Jennifer A
University College Chester, UK.
Laterality. 2005 May;10(3):219-42. doi: 10.1080/13576500442000049.
Studies of laterality of hand function in chimpanzees (Pan troglodytes) have the potential to tell us about the origins of handedness in Homo sapiens. However, the data are confusing, with discrepancies present between studies done in the field and the laboratory: the former show wild chimpanzees to be unlateralised at the population level, while the latter show captive chimpanzees as lateralised at the population level. This study of 26 semi-free ranging chimpanzees of Chester Zoo, UK, aimed to investigate a situation between the wild and captivity and provided ethological data for 43 categories of spontaneous manual use and 14 categories of tool use. Other variables recorded were subordinate hand activity, whether the subject was arboreal or terrestrial, and the identity of the subject. Using switching focal subject sampling, 23,978 bouts of hand use and 1,090 bouts of tool use were recorded. No population-level handedness was present for manual non-tool use activities in the naturalistically housed chimpanzees of Chester Zoo in a similar way to studies of wild chimpanzees. However, about half of the individuals were lateralised to one side or the other for the foraging behaviours of pick up, eat, and pluck. Using a modified version of McGrew and Marchant's (1997) Laterality Framework, these results are comparable to some wild and captive populations for similar foraging tasks. Bimanuality was rare and thus prevented comparison with captive experimental studies that have reported population right handedness. Behaviour involving contact with water elicited stronger lateralisation. Chester chimpanzees were more likely to exhibit hand preferences for manual tasks with increasing age but there were no effects of sex or rearing history on hand specialisations in adult individuals. Lateralisation was biased in tool use, which evoked significant left hand preferences in half the individuals, with no effect of age. Results are discussed comparatively with reference to methodological and developmental issues. Longitudinal studies of hand use are needed to increase our understanding of laterality of hand use in chimpanzees.
对黑猩猩（Pan troglodytes）手部功能偏向性的研究，有可能让我们了解智人用手习惯的起源。然而，数据令人困惑，实地研究和实验室研究之间存在差异：前者表明野生黑猩猩在群体层面上没有偏向性，而后者表明圈养黑猩猩在群体层面上有偏向性。这项对英国切斯特动物园26只半散养黑猩猩的研究，旨在调查介于野生和圈养之间的一种情况，并提供了43类自发手部使用行为和14类工具使用行为的行为学数据。记录的其他变量包括次要手的活动、研究对象是树栖还是陆栖，以及研究对象的身份。使用交替焦点研究对象抽样法，记录了23978次手部使用行为和1090次工具使用行为。与对野生黑猩猩的研究类似，在切斯特动物园自然饲养的黑猩猩中，非工具性手部使用活动在群体层面上没有用手习惯。然而，大约一半的个体在拿起、进食和采摘等觅食行为上偏向一侧。使用麦格鲁和马钱特（1997年）的偏向性框架的修改版本，这些结果与一些野生和圈养群体在类似觅食任务中的情况具有可比性。双手并用的情况很少见，因此无法与报告了群体右利手情况的圈养实验研究进行比较。涉及与水接触的行为引发了更强的偏向性。切斯特动物园的黑猩猩随着年龄增长，在手部任务中更有可能表现出手部偏好，但成年个体的性别或饲养历史对手部专门化没有影响。在工具使用方面存在偏向性，一半的个体在工具使用中表现出明显的左手偏好，且与年龄无关。研究结果将结合方法学和发育问题进行比较讨论。需要对手部使用情况进行纵向研究，以增进我们对黑猩猩手部使用偏向性的理解。
