Recent results of international assessment programs (e.g., PISA) have shown a large difference in high school students' performance between northern and southern Italy. On this basis, it has been argued that the discrepancy reflects differences in average intelligence of the inhabitants of regions and is associated with genetic factors ( and ).…

According to the cognitive cascade hypothesis, age-related slowing results in decreased working memory, which in turn affects higher-order cognition. Because recent studies show complex associative learning correlates highly with fluid intelligence, the present study examined the role of complex associative learning in cognitive cascade models of…

The current study tests if the type of children's daily main meal (slow versus fast food) mediates the association of socioeconomic status (SES) with cognitive ability and cognitive growth in childhood. A Scottish birth cohort (Growing Up in Scotland) was assessed at ages 3 (N = 4512) and 5 years (N = 3833) on cognitive ability (i.e. vocabulary…

The general differentiation hypothesis states that the strength of the correlations among a set of IQ subtests varies with a given variable. Instances of the general differentiation hypothesis that have been considered in the literature include age and ability differentiation. Traditionally, the differentiation effect is attributed to the varying…

There are very few studies on the relationship between cognitive ability and dental status in middle aged and younger adults. We postulate that lower cognitive ability is directly related to poorer dental status and that this relationship operates through the relationship between cognitive ability and health-related behaviors. The objectives of…

The effects of age and schooling on different aspects of intellectual performance, taking track of study into account, are investigated. The analyses were based on military enlistment test scores, obtained by 48,269 males, measuring Fluid ability (Gf), Crystallized intelligence (Gc), and General visualization (Gv) ability. A regression method,…

The association between intelligence and diet at 3.5 and 7 years was examined in 591 children of European descent. Approximately half of the children were born small-for-gestational age (birth weight @?10th percentile). The relationship between IQ and diet (measured by food frequency) was investigated using multiple regression analyses. Eating…

We studied the age-related differences in inspection time and multiple cognitive domains in a group of monozygotic (MZ) and dizygotic (DZ) twins aged 7 to 17 years. Data from 111 twin pairs and 19 singleton siblings were included. We found clear age-related trends towards more efficient visual information processing in older participants. There…

The relation between intelligence and birth order was shown in a recent publication [Bjerkedal, T., Kristensen, P., Skjeret, G. A. & Brevik, J. I. (2007). Intelligence test scores and birth order among young Norwegian men (conscripts) analyzed within and between families. "Intelligence," 35, 503-514] to be negative. Subjects in this…

D. K. Detterman and M. H. Daniel's recognition (1989) that intertest correlations for intelligence quotient (IQ) might not be uniform across the range of ability (and age) was anticipated by C. E. Spearman (1904). Detterman and Daniel appear to have rediscovered Spearman's suggested law of diminishing returns. (SLD)

Data from the national standardization of the French version of the WISC-III were analyzed to determine when during childhood the IQ-related process of differentiation appears and how the strength of the relationships among subtests evolves with age in low- and high-IQ groups. Indeed, some recent studies suggest that age might moderate the effect…

This study investigated whether measures of habituation and dishabituation in early infancy predicted later intelligence. Results were compared with those from other comparable studies. It was argued that the psychometric acceptability of infant cognitive measures needs to be demonstrated before they can be considered to be potential predictors.…

The hypothesis that a task that increases in complexity (increasing its correlation with a central measure of intelligence) does so by increasing its dimensionality by tapping individual differences or another variable was supported by findings from 46 adults aged 20-70 years performing a mental counting task. (SLD)

Measures of memory for order were correlated with measures requiring mental manipulation, achievement, and aptitude using college and fifth grade students. A significant relationship was found for fifth graders but not for college students, suggesting that the nature and capacity of short-term memory changes with age. (Author/PN)

A reanalysis of Stephens' intercorrelations of Wechsler subtests, achievement tests, and Piagetian tasks was conducted. (EJ 055 112) Piagetian tasks contributed almost equally to the definition of the general factor in intelligence along with the Wechsler subtests and the achievement tests. Communality outweighed differences between intelligence…