Strasser Andrea, Burkart Judith M
Anthropological Institute and Museum, University of Zürich, Zürich, Switzerland.
Brain Behav Evol. 2012;80(1):26-40. doi: 10.1159/000338014. Epub 2012 Jul 27.
Various measures of brain size correlate with cognitive performance; however, the fit is not perfect, which bears the question of whether brains also vary in efficiency. Such variation could be expected if a species faces constraints on brain enlargement, for example due to the impossibility of slowing down life history as a consequence of predator pressure, while simultaneously experiencing selective benefits from enhanced cognitive ability related to particular ecological or social conditions. Arguably, this applies to callitrichid monkeys and would lead to the prediction that their relatively small brains are particularly efficient in comparison to their sister taxa, Cebus. This study investigated whether callitrichids' cognitive performance is better than would be expected given their brain size rather than comparing absolute performance between the taxa. As a measure of cognitive performance, we used the reversal learning paradigm, which is reliably and closely associated with brain size across primate taxa, and assessed performance in this paradigm (transfer index) in 14 common marmosets (Callithrix jacchus) as representatives of the callitrichids. These marmosets were found to show higher performance than would be expected for their brain size, and this relative performance was also higher than the relative performance in capuchin monkeys. We outline how these effects may be due to the cooperative breeding system of the callitrichids, particularly the enhancement of behavioural and cognitive propensities associated with shared care and provisioning.
大脑大小的各种测量指标与认知表现相关；然而，这种关联并不完美，这就引出了一个问题，即大脑在效率方面是否也存在差异。如果一个物种面临大脑增大的限制，例如由于捕食者压力导致无法减缓生活史，同时又从与特定生态或社会条件相关的增强认知能力中获得选择性益处，那么这种差异是可以预期的。可以说，这适用于绢毛猴，这将导致这样的预测，即与它们的姐妹类群僧帽猴相比，它们相对较小的大脑特别高效。本研究调查了绢毛猴的认知表现是否优于根据其大脑大小所预期的表现，而不是比较不同类群之间的绝对表现。作为认知表现的一种衡量方法，我们使用了反转学习范式，该范式在灵长类动物类群中与大脑大小可靠且密切相关，并评估了14只普通狨猴（Callithrix jacchus）作为绢毛猴代表在该范式中的表现（转换指数）。这些狨猴的表现高于根据其大脑大小所预期的水平，并且这种相对表现也高于卷尾猴的相对表现。我们概述了这些影响可能如何归因于绢毛猴的合作繁殖系统，特别是与共同照料和供应相关的行为和认知倾向的增强。
