D'Agostino Justin, Cunningham Clare
Anthropology Department, California State University, Los Angeles, CA.
Anthropology Department, Southern Illinois University, Carbondale, IL.
Am J Primatol. 2015 Aug;77(8):854-68. doi: 10.1002/ajp.22410. Epub 2015 Apr 2.
Previous studies in learning set formation have shown that most animal species can learn to learn with subsequent novel presentations being solved in fewer presentations than when they first encounter a task. Gibbons (Hylobatidae) have generally struggled with these tasks and do not show the learning to learn pattern found in other species. This is surprising given their phylogenetic position and level of cortical development. However, there have been conflicting results with some studies demonstrating higher level learning abilities in these small apes. This study attempts to clarify whether gibbons can in fact use knowledge gained during one learning task to facilitate performance on a similar, but novel problem that would be a precursor to development of a learning set. We tested 16 captive gibbons' ability to associate color cues with provisioned food items in two experiments where they experienced a period of learning followed by experimental trials during which they could potentially use knowledge gained in their first learning experience to facilitate solution I subsequent novel tasks. Our results are similar to most previous studies in that there was no evidence of gibbons being able to use previously acquired knowledge to solve a novel task. However, once the learning association was made, the gibbons performed well above chance. We found no differences across color associations, indicating learning was not affected by the particular color / reward association. However, there were variations in learning performance with regard to genera. The hoolock (Hoolock leuconedys) and siamang (Symphalangus syndactylus) learned the fastest and the lar group (Hylobates sp.) learned the slowest. We caution these results could be due to the small sample size and because of the captive environment in which these gibbons were raised. However, it is likely that environmental variability in the native habitats of the subjects tested could facilitate the evolution of flexible learning in some genera. Further comparative study is necessary in order to incorporate realistic cognitive variables into foraging models.
以往关于学习集形成的研究表明，大多数动物物种能够学会学习，后续遇到新的呈现时，解决问题所需的呈现次数比首次遇到任务时更少。长臂猿（长臂猿科）在这些任务中通常比较吃力，并未表现出其他物种所具有的学会学习的模式。考虑到它们的系统发育位置和皮质发育水平，这一情况令人惊讶。然而，研究结果存在矛盾，一些研究表明这些小型猿类具有更高水平的学习能力。本研究旨在阐明长臂猿是否实际上能够利用在一项学习任务中获得的知识，来促进其在类似但新颖的问题上的表现，而这将是学习集发展的一个先兆。我们在两项实验中测试了16只圈养长臂猿将颜色线索与提供的食物项目相关联的能力，在实验过程中，它们经历了一段学习期，随后进行实验性试验，在此期间它们有可能利用首次学习经验中获得的知识来促进解决后续的新任务。我们的结果与大多数先前的研究相似，即没有证据表明长臂猿能够利用先前获得的知识来解决新任务。然而，一旦建立了学习关联，长臂猿的表现就远高于随机水平。我们发现不同颜色关联之间没有差异，这表明学习不受特定颜色/奖励关联的影响。然而，在属的层面上学习表现存在差异。白眉长臂猿（Hoolock leuconedys）和合趾猿（Symphalangus syndactylus）学习速度最快，而白掌长臂猿属（Hylobates sp.）学习速度最慢。我们提醒，这些结果可能是由于样本量小以及这些长臂猿是在圈养环境中长大的。然而，受试长臂猿原生栖息地的环境变异性可能会促进某些属的灵活学习的进化。有必要进行进一步的比较研究，以便将现实的认知变量纳入觅食模型。
