Abstract
Previous research has revealed that lower grade elementary school pupils who differ in their ability to learn to read also differ with respect to the optimal time of day for reading achievement. The present study strove to determine the hours of optimal attention in older pupils who varied in their apparent aptitude for mathematics. A sample of 204 fifth graders and 202 tenth graders were divided into three groups (high, average and low ability) on the basis of their mean yearly mathematics achievement scores. The subjects were asked to report on their attention levels throughout the day. The findings showed that fifth graders' attention levels were especially high in the afternoon, whereas tenth graders reported increased concentration during the morning hours. Among tenth graders, but not among fifth graders, there was a significant interaction between mathematics achievement and attention levels at various times of day. The practical implications of these findings for the planning of school schedules are discussed.

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