Data from: Intertemporal choice in lemurs

Different species vary in their ability to wait for delayed rewards in intertemporal choice tasks. Models of rate maximization account for part of this variation, but other factors such as social structure and feeding ecology seem to underly some species differences. Though studies have evaluated intertemporal choice in several primate species, including Old World monkeys, New World monkeys, and apes, prosimians have not been tested. This study investigated intertemporal choices in three species of lemur (black-and-white ruffed lemurs, Varecia variegata, red ruffed lemurs, Varecia rubra, and black lemurs, Eulemur macaco) to assess how they compare to other primate species and whether their choices are consistent with rate maximization. We offered lemurs a choice between two food items available immediately and six food items available after a delay. We found that by adjusting the delay to the larger reward, the lemurs were indifferent between the two options at a mean delay of 17 s, ranging from 9-25 s. These data are comparable to data collected from common marmosets (Callithrix jacchus). The lemur data were not consistent with models of rate maximization. The addition of lemurs to the list of species tested in these tasks will help uncover the role of life history and socio-ecological factors influencing intertemporal choices.

不同物种在跨期选择（intertemporal choice）任务中等待延迟奖励的能力存在显著差异。速率最大化模型（rate maximization）可解释部分物种间的能力差异，但社会结构、摄食生态等其他因素似乎也是部分物种差异的成因。尽管已有研究对多种灵长类的跨期选择行为进行了评估，涵盖旧世界猴（Old World monkeys）、新世界猴（New World monkeys）及类人猿，但原猴亚目动物尚未被纳入相关测试。本研究针对3种狐猴开展跨期选择实验，分别为黑白领狐猴（black-and-white ruffed lemurs, Varecia variegata）、红领狐猴（red ruffed lemurs, Varecia rubra）与黑狐猴（black lemurs, Eulemur macaco），旨在对比其跨期选择行为与其他灵长类的差异，并验证其选择是否符合速率最大化模型。实验中，我们为狐猴提供两种食物选择方案：一种为即刻可获取的2份食物，另一种为经过一段延迟后可获得的6份食物。研究结果显示，通过调整大额奖励的延迟时长，狐猴在平均延迟17秒（区间为9至25秒）时对两种选项表现出无差异偏好。该实验数据与普通狨猴（common marmosets, Callithrix jacchus）的相关实验数据具有可比性，但狐猴的选择行为并不符合速率最大化模型。将狐猴纳入此类行为实验的测试物种名录，将有助于揭示生命史与社会生态因素对跨期选择行为的影响机制。