Abstract
The aim of this study was to investigate variations in cognitive performance and difficulty perception in 9–10-year-old boys. Fifteen healthy boys (Age = 9.8 ± 0.4 years; Height = 146 ± 5.2 cm; Body mass = 34.2 ± 2.9 kg) performed three cognitive tasks, the reaction time (RT), the trail-making test, TMT (to evaluate flexibility), and the barrage tests (to evaluate selective attention [SA]). The tests were performed at 07:00 and 17:00 h. The results demonstrated that oral temperature, RT, and flexibility were significantly higher at 17:00 h than at 07:00 h. A significant main effect of diurnal variation was found for RT (t = 3.075, p = 0.008), SA (t = 2.43, p = 0.029), and executive function (TMT, Parts A and B) (t = 5.86, p < 0.001; t = 4.85, p < 0.001, respectively). However, these rhythms of cognitive performance were not correlated with the rhythm of core temperature at 07:00 h. In conclusion perceived difficulty was correlated with executive function in situations with higher level of difficulties.
Acknowledgements
We are grateful to all of the students who participated so willingly in the study.