摘要:AbstractInvestigating the relationships between student's intrinsic (IM) and extrinsic motivation (EM) and their effects is critical for offering a more complex perspective on which types of motivation promote optimal learning and achievement.The goal of this study was to analyse IM and EM as two independent forms of motivation or, alternatively, as two opposite poles of a continuum ranging from apoor(extrinsic) to agood(intrinsic) form of motivation.Participants were 200 students, who were longitudinally assessed along elementary school using separate measures of IM and EM, and academic of achievement.Resultssupported that IM and EM can coexist and are not contradictory. Whereas IM was steadily associated to better achievement, a negative relationship emerged between EM and student's achievement by the end of elementary school.