In 1977 Draw-a-Person test was administered to fifth grade school children in a city and its surrounding rural villages in Turkey. In 2010, more than thirty years later, the test was administered again to a corresponding group of fifth grade children in the same locations. It is rare that we get scores from the "same" population over a…

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 ).…

Three prominent theories of intelligence, the Cattell-Horn-Carroll (CHC), extended fluid-crystallized (Gf-Gc) and verbal-perceptual-image rotation (VPR) theories, provide differing descriptions of the structure of intelligence (McGrew, 2009; Horn & Blankson, 2005; Johnson & Bouchard, 2005b). To compare these theories, models representing them were…

The interpretation of retest scores is problematic because they are potentially affected by measurement and predictive bias, which impact construct validity, and because their size differs as a function of various factors. This paper investigates the construct stability of scores on a figural matrices test and models retest effects at the level of…

On the basis of several reviews of the literature, Lynn [Lynn, R., (2006). Race differences in intelligence: An evolutionary analysis. Augusta, GA: Washington Summit Publishers.] and Lynn and Vanhanen [Lynn, R., & Vanhanen, T., (2006). IQ and global inequality. Augusta, GA: Washington Summit Publishers.] concluded that the average IQ of the…

Intelligence is an important indicator of physical, mental and social well-being. In old age, intelligence is also associated with a higher quality of life and better health. Heritability studies have shown that there are strong genetic influences, yet unknown, on intelligence, including in old age. Other approaches may be useful to investigate…

Measures of broad fluid abilities including verbal, quantitative, and figural reasoning are commonly used in the K-12 school context for a variety of purposes. However, differentiation of these domains is difficult for young children (grades K-2) who lack basic linguistic and mathematical literacy. This study examined the latent factor structure…

Although the Flynn Effect has been studied widely across cultural, geographic, and intellectual domains, and many explanatory theories have been proposed, little past research attention has been paid to subgroup differences. Rodgers and Wanstrom (2007) identified an aggregate-level Flynn Effect (FE) at each age between 5 and 13 in the Children of…

Marked gender differences in three-dimensional mental rotation have been broadly reported in the literature in the last few decades. Various theoretical models and accounts were used to explain the observed differences. Within the framework of linking item design features of mental rotation tasks to cognitive component processes associated with…

The purpose of this study was to compare the cognitive abilities and selected achievement performance of females and males across the lifespan on standardization samples of broad cognitive abilities in 1987 participants (1102 females, 885 males) from the WJ III, 4253 participants (2014 males, 2239 females) from the WJ-R, and 4225 participants…

To examine whether the Roma (Gypsy) population of Serbia, like other South Asian population groups, average lower than Europeans on "g", the general factor of intelligence, we tested 323 16- to 66-year-olds (111 males; 212 females) in three different communities over a two-year-period on the Raven's Colored and/or Standard Progressive…

Using multi-group covariance and means structure analysis (MG-CMSA), this study investigated whether sex differences were present on the Dutch WAIS-III, and if so, whether these sex differences were attributable to differences in general intelligence ("g"). The sample consisted of 294 females and 228 males between 18 and 46 years old.…

Individual differences in procedural and declarative learning of a sequence-learning task by 455 adolescents were measured and compared to one another and to scores on a performance battery. A framework is proposed to explain the results based on a combination of approaches to explain dissociations found in memory. (SLD)

A number of studies in the United States have found that Jews obtain higher average IQs than white gentiles. This paper examines whether this is also the case in Britain. Three early studies are summarized that found that Jews in Britain have mean IQs in the range of 110-113. New data are presented for two nationally representative samples of 7-16…

To clarify the relationships between reaction time (RT) variability and intelligence, RT distributions from 303 male Navy recruits were partitioned into 16 fast-to-slow latency bands calculated with measures of mental ability. The slowest bands (worst trials) were the best predictors of intelligence and working memory performance. (SLD)