Children's time of day preference: age, gender and ethnic differences

Comprehensive data for children's time of day preference were collected with school children from 8 through 16 years of age (n = 989) using the Children's Morningness-Eveningness Preferences (CMEP) scale. Strong evidence was found that children's optimal time of day preference shifts toward evening at about 13 years of age. Additionally, gender and ethnic differences in time of day preference were also examined. There was no gender difference, but there was a tendency for ethnic differences among older children. An implication of these findings is that a mismatch between older children's time of day preferences and school start time may have a negative effect on their school performance and this effect could be greater for some ethnic groups than for others.