Abstract: This study is a preliminary approach to the day-cycle of the attentionlevel and memory activities in human beings. The subjects were eighteen 13-year-old middle school boarding students(10male students and 8 female students). Every morning at 8 and 11 o'clock and every afternoon at 4 and 7o'clock attention levels were determined and at 11 a. m. and 4 p. m. memoryactivities were determined. The research indicates that the attention level of a person shows regularchanges periodically. Around 11 a. m. it obviously drops and in the afternoonit rises. The rise in mental activities in the afternoon is also confirmed bythe tests on memory. Individual analysis shows: In the tests on attention 77.7％ of thesubjects were of this pattern, and 66.7％ in the memory tests. The reason of this periodical pattern needs further research.

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