Circadian Cycle and Adolescentss Nonverbal Intelligence

Abstract

‘Circadian Cycle’, the biological clock within the organism, is the cyclic changes in bodily process occurring within a single day basing on our conscious awareness which is generated endogenously by the anterior hypothalamic suprachiasmatic nuclei and modulated by exogenous factors. In other words, the state of activity and arousal level in the series of different cycles of sleep and wakefulness, in most of the cases, is generated, controlled, guided, and explained in terms of Circadian Cycle. This activating level of the mind has its origin from the very childhood stage of the organism and reaches its peak in adolescence, basing on different ecological, anthropological, sociological, and psychological points of view. An investigation was made on the effect of circadian cycle on the intelligence level of 100 urban and 100 tribal school children (age 10-14 of class IV and class VI) of Nayagarh District, different Govt. schools, ‘Sai Saraswati Sishumandiir School’, and from the KISS School of KIIT University, Bhubaneswar, Odisha. After being randomly selected the subjects were individually administered the Raven’s Advanced progressive matrices tests of intelligence in their natural environment. All of them were tested for four times a day: in morning, noon, evening and night; and accordingly their IQ scores were recorded. The analysis of results revealed that irrespective of culture, the IQ of the subjects was differentially affected by varying degrees of circadian cycles. It was more in noon than evening and morning and more in morning than night. The difference in intelligence scores between urban and tribal children, analyzed by Two Way ANOVA, was found to be statistically significant. The interaction of circadian cycle and culture was also found to have highly significant effect on intelligence scores of the subject. The most interesting part of the findings was, in night shifts, tribal adolescents were more active than their urban counterparts indicating their ecological and anthropological stand point of circadian cycle (t=3.62). The means of the intelligence scores of urban and tribal children were 9.81 (SD=1.62) and 9.56 (SD=1.75) respectively. This group difference was found to be statistically significant. In other words both urban and tribal children are more or less not equal with regard to their intelligence scores. The means of the intelligence scores of the subjects , at morning , noon , evening and night, irrespective of socio-cultural groups were 8.29 (SD=1.76), 11.59 (SD=1.72), 10.31 (SD=1.66) and 8.57 (SD=1.62), respectively. This mean difference was found to be statistically significant. In other words Circadian Rhythms have significant effects on the intelligence score of the subjects. More important is subsequent Newmann-Keuls post hoc test revealed significant differences among all possible group comparisons in favor of noon shift.