All around the world, school-entry cohorts are organized on an annual calendar so that the age of students in the same cohort differs by up to one year. It is a well-established finding that this age gap entails a consequential (dis)advantage for academic performance referred to as the relative age effect (RAE). This study contributes to a recent strand of research that has turned to investigate the RAE on non-academic outcomes such as personality traits. An experimental setup is used to estimate the causal effect of monthly age on cognitive effort in a sample of 798 fifth-grade students enrolled in the Spanish educational system, characterized by strict enrolment rules. Participants performed three different real-effort tasks under three different incentive conditions: no rewards; material rewards; and material and status rewards. We observe that older students outwork their youngest peers by two-fifths of a standard deviation, but only when material rewards for performance are in place. Despite the previously reported higher taste for competition among the older students within a school-entry cohort, we do not find that the RAE on cognitive effort increases after inducing competition for peer recognition. Finally, the study also provides suggestive evidence of a larger RAE among boys and students from lower social strata. Implications for sociological research on educational inequality are discussed. To conclude, we outline policy recommendations such as implementing evaluation tools that nudge teachers toward being mindful of relative age differences.

中文翻译：

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出生月份与认知努力：五年级学生相对年龄效应的实验室研究

在世界各地，入学队列都是按年历组织的，因此同一队列中学生的年龄最多相差一年。一项公认的发现是，这种年龄差距会对学业成绩产生间接（不利）优势，称为相对年龄效应（RAE）。这项研究为最近的一系列研究做出了贡献，该研究转向调查人格特质等非学术成果的 RAE。采用实验设置来评估 798 名就读于西班牙教育系统的五年级学生样本中的月龄对认知努力的因果影响，该系统的特点是严格的入学规则。参与者在三种不同的激励条件下执行了三种不同的真实努力任务：没有奖励；物质奖励；以及物质和地位奖励。我们观察到，年龄较大的学生比年龄最小的同龄人的成绩高出五分之二的标准差，但前提是对表现给予物质奖励。尽管之前报道称，入学队列中年龄较大的学生对竞争的兴趣更高，但我们没有发现在引发同伴认可的竞争后，认知努力的 RAE 会增加。最后，该研究还提供了暗示性证据，表明来自较低社会阶层的男孩和学生的 RAE 更大。讨论了教育不平等社会学研究的意义。最后，我们概述了政策建议，例如实施评估工具，促使教师注意相对年龄差异。