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.

在跨期选择（intertemporal choice）任务中，不同物种的延迟奖励等待能力存在显著差异。速率最大化模型（rate maximization）可解释部分此类差异，但社会结构、取食生态等其他因素似乎也是部分物种间差异的潜在成因。尽管已有研究对多种灵长类动物的跨期选择行为开展了评估，涵盖旧世界猴、新世界猴及类人猿，但原猴亚目（prosimians）物种尚未被纳入测试范围。本研究针对3种狐猴开展跨期选择行为实验：黑白领狐猴（Varecia variegata）、红领狐猴（Varecia rubra）与黑狐猴（Eulemur macaco），旨在探究其跨期选择模式与其他灵长类的异同，并验证其选择行为是否符合速率最大化模型。实验中，我们为狐猴提供两种取食选择：即刻可得的2份食物，与延迟后可得的6份食物。结果显示，通过调整大额奖励的延迟时长，当平均延迟时长为17秒（范围9~25秒）时，狐猴对两种取食选项的偏好无显著差异。该实验数据与普通狨猴（Callithrix jacchus）的相关研究结果具有可比性，但狐猴的选择行为并不符合速率最大化模型的预测。将狐猴纳入跨期选择任务的测试物种名录，将有助于进一步揭示生活史及社会生态因素对跨期选择行为的影响机制。