Radl, JonasValdés, Manuel T.2023-01-272023-01-272023-01https://hdl.handle.net/10016/36388All around the world school entry cohorts are organized on an annual calendar, so that the age of students in the same cohort differs 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 assess the willingness to exert cognitive effort in a sample of 798 fifth grade students enrolled in the Spanish educational system, characterized by strict enrolment rules. After controlling for cognitive ability, we observe that older students outwork their youngest peers by two-fifths of a standard deviation, but only when rewards for performance are in place. Implications for sociological research on educational inequality and policy are discussed.25eng© The authors, 2023.Atribución-NoComercial-SinDerivadas 3.0 EspañaRelative age effectMonth of birthCognitive effortExperimental designSpainworking paperSociologíaopen access125DT/0000002045