Sex-Specific Age-Related Changes of Information Processing Rate Indicators during Childhood and Adolescence

Mislav Stjepan Žebec, Sanja Budimir, Marina Merkaš, Lajoš Szirovicza, Miroslav Živičnjak


Despite the relevant findings on non-average information processing rate (IPR) indicators-intelligence relation, and on age-related changes of some of these indicators during aging, the research on sex-specific age-related changes of these indicators during childhood and adolescence are lacking. In a transversal study, 1197 school children (598 girls) aged 8-18 have been individually measured on 5 IPR indicators – two averages (mean_t, median_t) and three non-averages (min_t, max_t, sd_t). The results corroborated the expected non-linear changes of average IPR indicators in the observed developmental period, whereby the sex difference in related developmental patterns was detected: marked age-related decrement in girls (Fmean_t=178.25, Fmedian_t=168.32, dfage=10, dferror=587, p<0.01) ceased at the age of 12, and in boys (Fmean_t=160.98, Fmedian_t=156.30, dfage=10, dferror=588, p<0.01) around the age of 13-14, after which progress in both sexes gradually ceased by the age of 18 and was less pronounced in girls. The justifiability of separate, average and non-average, IPR indicators application was corroborated by their distribution form differences, by mutual, predominantly low and medium correlations, by the different intensity of their developmental changes and by their different ability to detect sex differences. Generally, similar non-linear age-related decrements of non-average indicators were registered, but they showed mutual intensity differences at specific ages and sex difference in developmental patterns was detected, analogously to average indicators: [Fmin_t=123.60, Fmax_t=87.25, Fsd_t=29.88, dfage=10, dferror=587, p<0.01]female; [Fmin_t=110.51, Fmax_t=76.74, Fsd_t=22.62, dfage=10, dferror=587, p<0.01]male . Systematic sex differences in the whole observed period were obtained only in two indicators: girls showed minor sd_t (F=10.375, dfsex=1, dferror=1175, p<0.01), and boys showed minor min_t (F=7.744, dfsex=1, dferror=1175, p<0.01). In specific age groups, a number of sex differences were obtained that are explainable by two possible mechanisms: earlier maturation in girls and sex bias of the IPR task content. For all registered phenomena, the theoretical and/or empirical explanations were offered from the domain of sex specific intellectual, motor and neural development, and it has been shown that non-average IPR indicators do register sex and age differences, which average indicators do not manage to register.


information processing rate, average and non-average indicators, sex differences, age-related changes, childhood and adolescence

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