School of Science and Technology, University of New England, Armidale, NSW, 2351, Australia.
Sci Rep. 2020 Nov 24;10(1):20437. doi: 10.1038/s41598-020-76572-7.
Play behaviour and tool using in birds, two well-delineated and amply researched behaviours, have generally been associated with cognitive abilities. In this study, these behaviours were related to relative brain mass in a sample of Australian native birds. Despite suggestive research results so far between cognition and tool using, this study found no significant difference in relative brain mass or in lifespan between tool-using birds and non-tool users. By contrast, in play behaviour, subdivided into social players and non-social players, the results showed statistically very clear differences in relative brain mass between social, non-social and non-players. Social play was associated with both the largest brain mass to body mass ratios and with the longest lifespans. The results show that play behaviour is a crucial variable associated with brain enlargement, not tool using. Since many of the tool using species tested so far also play, this study suggests that false conclusions can be drawn about the connection between tool using and cognitive ability when the silent variable (play behaviour) is not taken into account.
鸟类的玩耍行为和使用工具行为，这两种行为都经过了充分的研究，通常与认知能力有关。在这项研究中，研究人员将这些行为与澳大利亚本土鸟类样本中的相对脑质量联系起来。尽管迄今为止关于认知与使用工具之间的关系的研究结果表明两者之间存在关联，但这项研究发现，使用工具的鸟类与不使用工具的鸟类之间的相对脑质量或寿命没有显著差异。相比之下，在玩耍行为中，根据是否具有社交性进一步细分为社交玩耍者和非社交玩耍者，结果显示，社交玩耍者、非社交玩耍者和非玩耍者之间的相对脑质量存在统计学上的显著差异。社交玩耍与最大的脑体比和最长的寿命有关。结果表明，玩耍行为是与大脑增大相关的关键变量，而不是使用工具。由于迄今为止测试的许多使用工具的物种也会玩耍，因此这项研究表明，如果不考虑沉默变量（玩耍行为），那么关于使用工具和认知能力之间联系的结论可能会产生偏差。
