Learning outdoors: Male lizards show flexible spatial learning under semi-natural conditions

Spatial cognition is predicted to be a fundamental component of fitness in many lizard species, and yet some studies suggest that it is relatively slow and inflexible. However, such claims are based on work conducted using experimental designs or in artificial contexts that may underestimate their cognitive abilities. We used a biologically realistic experimental procedure (using simulated predatory attacks) to study spatial learning and its flexibility in the lizard Eulamprus quoyii in semi-natural outdoor enclosures under similar conditions to those experienced by lizards in the wild. To evaluate the flexibility of spatial learning, we conducted a reversal spatial-learning task in which positive and negative reinforcements of learnt spatial stimuli were switched. Nineteen (32%) male lizards learnt both tasks within 10 days (spatial task mean: 8.16 ± 0.69 (s.e.) and reversal spatial task mean: 10.74 ± 0.98 (s.e.) trials). We demonstrate that E. quoyii are capable of flexible spatial learning and suggest that future studies focus on a range of lizard species which differ in phylogeny and/or ecology, using biologically relevant cognitive tasks, in an effort to bridge the cognitive divide between ecto- and endotherms.

空间认知（Spatial cognition）被认为是多数蜥蜴物种适合度（fitness）的核心构成要素，但部分研究指出其空间认知能力相对迟缓且缺乏灵活性。然而此类结论多基于存在缺陷的实验设计或人工环境下开展的研究，这类研究可能低估了蜥蜴的真实认知水平。本研究采用具有生态学效度的实验范式——通过模拟捕食攻击（simulated predatory attacks）的方式——在半自然室外围栏（semi-natural outdoor enclosures）中，以贴近野生蜥蜴自然生存的环境条件，对昆氏石龙子（Eulamprus quoyii）的空间学习（spatial learning）能力及其灵活性展开探究。为评估空间学习的灵活性，我们设置了反转空间学习任务：将已习得空间刺激的正向与负向强化（reinforcement）条件进行互换。最终共有19只（占比32%）雄性昆氏石龙子在10天内完成了两项任务的学习（空间任务平均完成试次：8.16 ± 0.69，标准误（standard error, s.e.）；反转空间任务平均完成试次：10.74 ± 0.98，标准误（standard error, s.e.））。本研究证实昆氏石龙子具备灵活空间学习的能力，并建议未来研究应采用具备生物学相关性的认知任务，针对一系列系统发育（phylogeny）与生态特征存在差异的蜥蜴物种开展探究，以期弥合变温动物（ectotherms）与恒温动物（endotherms）之间的认知鸿沟。