Cattell's Culture Fair Intelligence Research Articles

Auditory event-related potentials, neurocognition, and global functioning in drug naïve first-episode schizophrenia and bipolar disorder.

Deficits in event-related potential (ERP) including duration mismatch negativity (MMN) and P3a have been demonstrated widely in chronic schizophrenia (SZ) but inconsistent findings were reported in first-episode patients. Psychotropic medications and diagnosis might contribute to different findings on MMN/P3a ERP in first-episode patients. The present study examined MMN and P3a in first episode drug naïve SZ and bipolar disorder (BPD) patients and explored the relationships among ERPs, neurocognition and global functioning. Twenty SZ, 24 BPD and 49 age and sex-matched healthy controls were enrolled in this study. Data of clinical symptoms [Positive and Negative Symptoms Scale (PANSS), Young Manic Rating Scale (YMRS), Hamilton Depression Rating Scale (HAMD)], neurocognition [Wechsler Adult Intelligence Scale (WAIS), Cattell's Culture Fair Intelligence Test (CCFT), Delay Matching to Sample (DMS), Rapid Visual Information Processing (RVP)], and functioning [Functioning Assessment Short Test (FAST)] were collected. P3a and MMN were elicited using a passive auditory oddball paradigm. Significant MMN and P3a deficits and impaired neurocognition were found in both SZ and BPD patients. In SZ, MMN was significantly correlated with FAST (r = 0.48) and CCFT (r = -0.31). In BPD, MMN was significantly correlated with DMS (r = -0.54). For P3a, RVP and FAST scores were significant predictors in SZ, whereas RVP, WAIS and FAST were significant predictors in BPD. The present study found deficits in MMN, P3a, neurocognition in drug naïve SZ and BPD patients. These deficits appeared to link with levels of higher-order cognition and functioning.

Speed- and accuracy-related measures of an intelligence test are differentially predicted by the speed and accuracy measures of a cognitive task

Raw scores on time-limited multiple-choice intelligence tests are determined by incorrect responses and missing answers. Both these error types were previously found to be negatively related to each other. Individual differences in the emphasis on speed or accuracy can explain this finding. But even though individual differences in the emphasis on speed or accuracy have been identified not only in intelligence tests but also in cognitive tasks, little is known about their interplay. Therefore the aim of the present study was to investigate to what degree speed- and accuracy-related performance scores of an intelligence test can be predicted by speed and accuracy measures of cognitive tasks, respectively. For this purpose, 200 participants completed Cattell's Culture Fair Intelligence Test (CFT 20-R) and performed the Swaps Task, an experimental cognitive task. To investigate the interplay between the speed and the accuracy measures of both kinds of task, a latent variable approach was used. Overall, the emphasis on speed or accuracy was not systematically related to the intelligence score. However, closer inspection of the data revealed that reaction times, but not errors rates, in the Swaps Task predicted the number of not-reached items as an indicator of speed in the CFT 20-R. At the same time, error rates, but not reaction times, in the Swaps Task predicted incorrect responses as an indicator of accuracy in the CFT 20-R. Taken together, speed- and accuracy-related performance scores of an intelligence test were predicted by speed and accuracy measures of a cognitive task, respectively. Most important, however, the finding that the emphasis on speed or accuracy was not significantly related to intelligence scores clearly indicated that this emphasis does not interfere with the validity of the intelligence test.

Fluid intelligence, emotional intelligence, and the Iowa Gambling Task in children

This study explored the roles of fluid intelligence and emotional intelligence (EI) in predicting performance on the Iowa Gambling Task (IGT) in intellectually average and gifted children. One hundred and twenty-five average children and ninety-eight gifted children were tested with Cattell's Culture Fair Intelligence Test, the Trait Emotional Intelligence Questionnaire-Child Form and the IGT. It was currently found that intellectually gifted children demonstrated better IGT performance than their average peers, including superior decision-making strategies, decision-making speeds and conceptual knowledge stages in the IGT. Fluid intelligence and emotional intelligence played different roles in predicting IGT performance in average and gifted children: average children's IGT performance was related to fluid intelligence and EI, whereas gifted children's IGT performance was associated only with fluid intelligence. IGT performance was more strongly associated with cognitive processes compared to emotional processes. The present study helps to explain how cognitive and emotional processes interact in intellectually average and gifted children's decision making.

Hans J. Eysenck and Raymond B. Cattell on intelligence and personality

The two most prominent individual differences researchers of the twentieth century were Hans J. Eysenck and Raymond B. Cattell. Both were giants of scientific psychology, each publishing scores of books and hundreds of empirical peer-reviewed journal articles. Influenced by Hebb's distinction between physiological (Intelligence A) and experiential (Intelligence B), Eysenck focused on discovering the underlying biological substrata of intelligence. Analogously, Cattell proposed the Gf–Gc theory which distinguishes between fluid and crystallised intelligence. Cattell's Culture Fair Intelligence Test (CFIT), a measure primarily of fluid intelligence, was constructed specifically to minimise differences in test bias in IQ scores between different ethnic/racial groups. Within the personality realm, Eysenck adopted a pragmatic three-factor model as measured via the Eysenck Personality Questionnaire (EPQ-R) and its variants. In contrast, Cattell employed a lexical approach that resulted in a large number of primary and secondary normal and abnormal personality trait dimensions, measured via the Sixteen Personality Factor Questionnaire (16PF), and the corresponding Clinical Analysis Questionnaire (CAQ), respectively. Recent molecular genetics findings provide empirical confirmation of Eysenck and Cattell's positions on the biological underpinnings of personality and ability traits, allowing an improved understanding of the causes of individual differences.

Puberty timing and fluid intelligence: A study of correlations between testosterone and intelligence in 8- to 12-year-old Chinese boys

Sex hormone such as testosterone was recently recognized as an important contributor of spatial cognition and intelligence during development, but the relationship between puberty timing and intelligence especially in children is largely unknown. Here in this study, we investigated the potential relationship between the level of sex hormones in saliva and fluid intelligence in 8- to 12-year-old Chinese boys. Fluid intelligence was measured by the Cattell's Culture Fair Intelligence Test. 1600 children aged 8-12 years were included in the Cattell's Culture Fair Intelligence Test and saliva samples were collected thereafter from 166 boys with normal intelligence distribution, composed of 49, 54 and 63 boys in 8-, 10- and 12-year-old group respectively. The level of salivary testosterone and estradiol was measured with enzyme-immunoassay technique. Data of BMI and age were collected. The relationship between the level of salivary sex hormones and fluid intelligence was analysed by correlation test. There was no significant correlation between salivary testosterone level and fluid intelligence in 8-year-old boys, whereas there was a significant positive correlation in 10-year-old boys and a significant negative correlation in 12-year-old boys between those two variable. To verify the correlation, we performed stepwise multivariate linear regression and discriminant analysis, with both the age and BMI of the boys and their parents, and salivary estradiol level considered. The results showed that the level of testosterone and intelligence was correlated, and the correlation was much stronger when the level of salivary testosterone was higher than 14 pg/ml. In summary, the study suggests that the relationship of testosterone and intelligence varies from late childhood to early adolescence, and the puberty timing is closely related with fluid intelligence.

Neural substrates of the Topology Test to measure fluid reasoning: An fMRI study

In our prior study the negative correlation between Topology, a behavioral measure of fluid reasoning, and adult age diminished with the increase in the level of expertise in a cognitively-demanding domain of expertise in the game of GO. The present fMRI study was designed to investigate neural substrates of Topology. The modified topology sub-test of Cattell's Culture Fair Intelligence Tests was used as cognitive stimuli. The results indicated that higher-order cognition of Topology was supported by neural networks in: (1) the parietal cortex which is involved in activating possible responses based on learned stimulus-response associations, and (2) the prefrontal cortex that is recruited when there is a need to generate and evaluate hypotheses, and select between competing responses. Our results were consistent with previous neuroimaging studies of reasoning using Raven's Progressive Matrices that revealed the engagement of the prefrontal cortex and the parietal cortex in inductive reasoning. The future need was discussed to systematically examine neural networks supporting Topology over the course of expertise development and adult development in order to specify unique aspects of fluid reasoning that support high levels of cognitive behaviors of Topology.

CORRELATIONS BETWEEN NONVERBAL INTELLIGENCE AND NERVE CONDUCTION VELOCITIES IN RIGHT-HANDED MALE AND FEMALE SUBJECTS

A neurological theory of intelligence suggesting a direct correlation between nerve conduction velocity and psychometric intelligence was tested. Cattell's Culture Fair Intelligence Test was used to asses the nonverbal intelligence (IQ) of subjects. The motor median nerve conduction velocity from right hand of males was positively correlated with IQ. In subjects with no familial sinistrality (FS–), the motor ulnar-nerve conduction velocity from the right and left hands of males negatively correlated with IQ; there were inverse correlations between IQ and nerve conduction velocity (motor median nerve from right, sensory median nerve from right and left) in females. In subjects with familial sinistrality (FS+), IQ directly correlated with nerve conduction velocity from motor median (right and left), sensory median (right), and motor ulnar (right) nerves, but only in males. The speed hypothesis and neurological theory of intelligence were not supported by these results, which, in contrast, emphasized the importance of sex and familial sinistrality in any theory of intelligence.

Correlations among Handedness, Eyedness, Monocular Shifts from Binocular Focal Point, and Nonverbal Intelligence in University Mathematics Students

Relationships among hand preference, nonverbal intelligence, and the monocular shifts of binocular focal point were studied in 33 men and 12 women university mathematics students. Ocular dominance was assessed with the Miles test. The monocular shift of binocular focal point for each eye was assessed with a modified Miles test. Hand preference was assessed on the Edinburg Handedness Inventory. Nonverbal intelligence was assessed with Cattell's Culture Fair Intelligence Test. In a prior study, the percentage of left-eye preference had been reported to be greater for mathematics students than for nonmathematics students. In the present study there were positive correlations between hand preference and the sum of the monocular shifts of two eyes. In addition, there was a negative correlation between nonverbal intelligence and the sum of the monocular shifts of two eyes. As these resultssuggest that the sum of the monocular shifts of two eyes may be related to mathematical ability and nonverbal intelligence, further research with a larger sample including non-mathematics students is needed.

Sex Differences in Verbal and Spatial Ability Reconsidered in Relation to Body Size Lung Volume, and Sex Hormones

Sex differences in verbal and nonverbal abilities were reconsidered in relation to bodily measures and sex hormones in Turkish university students. Perceptual-verbal ability was evaluated using As Test. To assess the nonverbal abilities, the mental rotation test and Cattell's Culture Fair Intelligence Test were used. As expected, the 53 women performed better than men on the As Test; 79 men had a higher mean than the 53 women on the mental rotation task; there was no sex difference on Cattell's IQ Test. Cattell IQs correlated only with tidal volume of lungs. Scores on the As Test did not show significant correlations with body size and lung capacities. Mental rotation was significantly correlated with height, weight, and lung volume. With covariates of height, weight, and vital capacity, sex differences in mental rotation completely disappeared, but the difference on the As Test increased while Cattell IQ remained sex-neutral. With testosterone as covariate, the sex difference on the As test increased but on the mental rotation task disappeared; Cattell IQ was sex-neutral. With covariates of estradiol and progesterone, sex differences on the As test disappeared; mental rotation scores and Cattell IQ were not influenced. Under a combined covariation of height, weight, and testosterone, sex differences in mental rotation reversed, women scoring better than men; after adding estradiol or progesterone instead of testosterone to this model, sex differences on mental rotation completely disappeared, but verbal ability and Cattell IQ were not changed. These results suggest that Cattell's Culture Fair Intelligence Test is unique in resistance to sex differences; perceptual-verbal ability was the most sex-specific mental trait but with dependence on estradiol; mental rotation, on the contrary, was least sex-specific, depending on body size, lung volume, sex hormones, and their combined actions, which explains women's better performance.

Magnetic resonance imaging brain size/IQ relations in Turkish University students

The relation of IQ (Cattell's Culture Fair Intelligence Test) to brain size was studied in 103 right- and left-handed men and women at Atatürk University in eastern Turkey. Cerebral areas were measured on a midsagittal section of the brain using MRI. An overall correlation of 40 was found between MRI-measured total area and IQ thereby further supporting the IQ–brain size hypothesis. Additional analyses suggested that these results may need qualification. In men, only anterior cerebral area correlated with IQ. In women, total and posterior cerebral areas were correlated with IQ. Other results varied by handedness.

Correlations among scores on measures of field dependence-independence cognitive style, cognitive ability, and sustained attention.

The Children's Embedded Figures Test, the Rod and Frame Test to measure the field dependence-independence cognitive style, Cattell's Culture Fair Intelligence Tests to measure cognitive ability, and two cancellation tasks (Zazzo task and Bourdon task) to assess sustained attention were administered to 179 boys and 110 girls whose average age was 9.0 yr. Correlations between scores on measures of field dependence-independence and cognitive ability were moderated. Average correlations between scores on measures of field dependence-independence, cognitive ability, and measures of sustained attention was .23 for the Zazzo task and quite weak (.06) for the Bourdon task.

The Curvelinear Correlations Between the Total Testosterone Levels and Fluid Intelligence in Men and Women

The relationship between serum total testosterone (T) level and the fluid intelligence (Cattell's Culture Fair Intelligence Test) was studied in men and women. There was no significant difference between IQs of men and women. There was an inverse curvelinear relationship between IQ and T in women. The same was found also in men, but the declining part of the regression line at high T levels was not as pronounced as in women. It is concluded that T may be related to IQ, even in subjects exhibiting no sex difference in IQ tests; too low or too high T levels may be disadvantageous for the fluid intelligence, especially in women.

Curvelinear Correlations Between Total Testosterone Levels and Fluid Intelligence in Men and Women

The relationship between serum total testosterone (T) level and fluid intelligence (Cattell's Culture Fair Intelligence Test) was studied in young men and women. There was no significant difference between IQs of men and women. IQ tended to increase with T in men, except at very high T level. It was concluded that (i) T may be associated with IQ, even in samples with no sex-related IQ difference; (ii) too low or too high T may be disadvantageous for fluid intelligence in women; (iii) T may be advantageous for this kind of IQ in men, except very high T levels.

Fluctuating asymmetry and psychometric intelligence.

Little is known about the genetic nature of human psychometric intelligence (IQ), but it is widely assumed that IQ's heritability is at loci for intelligence per se. We present evidence consistent with a hypothesis that interindividual IQ differences are partly due to heritable vulnerabilities to environmental sources of developmental stress, an indirect genetic mechanism for the heritability of IQ. Using fluctuating asymmetry (FA) of the body (the asymmetry resulting from errors in the development of normally symmetrical bilateral traits under stressful conditions), we estimated the relative developmental instability of 112 undergraduates and administered to them Cattell's culture fair intelligence test (CFIT). A subsequent replication on 128 students was performed. In both samples, FA correlated negatively and significantly with CFIT scores. We propose two non-mutually exclusive physiological explanations for this correlation. First, external body FA may correlate negatively with the developmental integrity of the brain. Second, individual energy budget allocations and/or low metabolic efficiency in high-FA individuals may lower IQ scores. We review the data on IQ in light of our findings and conclude that improving developmental quality may increase average IQ in future generations.

Correlations between nonverbal intelligence and peripheral nerve conduction velocity in right-handed subjects: sex-related differences

The speed hypothesis of intelligence was tested in relation to median nerve conduction velocity (NCV) in right-handed subjects. In total, NCV did not significantly correlate with IQ (Cattell's Culture Fair Intelligence test). The motor and sensory median NCVs correlated with IQ positively linearly in men and negatively linearly in women. These results supported the general, unqualified speed hypothesis of intelligence only for men. It was concluded that the conduction speed of the input-output channels of brain as an information processing unit may differentially contribute to nonverbal intelligence, depending upon sex. The male hormone, testosterone, was suggested to be the main factor responsible for sex-related differences in the IQ-NCV relationships.

Inverse relationship between nonverbal intelligence and the parameters of pattern reversal visual evoked potentials in left-handed male subjects: importance of right brain and testosterone.

The relationships between latencies of visual evoked potentials (VEPs) and nonverbal intelligence test scores (IQs from Cattell's Culture Fair Intelligence Test) and correlations between serum testosterone level and VEP latencies were studied to examine the neural speed hypothesis of intelligence and its hormonal mechanisms in left-handed male subjects (Geschwind Scores). In accordance with the speed theory of intelligence, N1 and P1 latencies (and amplitudes) were found to be inversely related to IQ. However, this was true only for the right brain; the left brain did not contribute to this relationship. There was an inverse relationship between serum testosterone level and P1 latency; left minus right N1 latency, depending on N1 latency from right brain, linearly increased with testosterone. It was concluded that nonverbal intelligence largely depends on speed of information processing only by the right brain, not by the left brain in left-handed male subjects. This may have been created by testosterone in these subjects. Inconsistencies in the IQ literature concerning the speed hypothesis of intelligence may be explained by differences in cerebral lateralization.

Relationships among nonverbal intelligence, hand speed, and serum testosterone level in left-handed male subjects.

The relationships among nonverbal intelligence, hand speed, and serum testosterone level were studied in male left-handers ranging in age from 17 to 19 years. Hand speed was measured by a peg moving task. To assess the differences between nonverbal IQs. Cattell's Culture Fair Intelligence Test was used. There was a direct correlation between IQ and testosterone. IQ increased linearly with right-hand speed, which was directly related to testosterone. There was no significant correlation between IQ and left-hand speed, which was not significantly correlated with testosterone. IQ decreased with left- minus right-hand speed, which also decreased with testosterone. It was suggested that nonverbal spatial reasoning ability may be directly associated with the efficiency of left brain, which is favored by testosterone in male left-handers. It was also concluded that the left to right asymmetry in hand speed may depend on efficiency of the right brain in left-handed males.

Relation of nonverbal intelligence assessed by Cattell's Culture Fair Intelligence Test to latencies of the somatosensory evoked potentials elicited by stimulation of the posterior tibial nerves in right-handed male and female subjects.

The association of nonverbal intelligence (NVI) with latencies of the somatosensory evoked potentials from the right and left posterior tibial nerves (PTNs) was studied in right-handed male and female subjects without familial sinistrality (FS-). There was a significant negative linear correlation between N49-P39 interpeak latencies from the right and left PTNs in females and a significant positive linear correlation between these parameters in males. There was no significant correlation between P58-N49 interpeak latencies and NVI in females, but a significant negative linear correlation in males. The N76-P58 interpeak latencies were found to be positively linearly related to NVI only in females; there was no correlation between these parameters in males. There was no significant correlation between IQ and side differences in SEP latencies in females. The right minus left P39 latencies from the right and left PTN were found to be negatively linearly related to IQ in males. In females with nearly equal heights, latencies of N49 waves were found to be negatively linearly related to IQ. In males with nearly equal heights, only P39 and P58 waves from the right PTN were found to be negatively linearly related to IQ. These results did not support the hypothesis of speed of information processing by the brain in behavioral intelligence. An asymmetrical organization of the male brain seems to be disadvantageous for nonverbal intelligence; the female brain appeared to be independent of the degree of asymmetrical organization of the brain in this respect.

Transcendental meditation and improved performance on intelligence-related measures: A longitudinal study

This two-year longitudinal study investigated the effect of participation in a special university curriculum, whose principal innovative feature is twice-daily practice of the Transcendental Meditation (TM) and TM-Sidhi program, on performance on Cattell's Culture Fair Intelligence Test (CFIT) and Hick's reaction time. These measures are known to be correlated with general intelligence. One hundred college men and women were the subjects—45 from Maharishi International University (MIU) and 55 from the University of Northern Iowa (UNI). The experimental group (MIU) improved significantly on the CFIT ( t=2.79, P<0.005); choice reaction time ( t=9.10, P<0.0001); SD of choice reaction time ( t=11.39, P<0.0001), and simple reaction time ( t=2.11, P<0.025) over two years compared to the control group, which showed no improvement. Possible confounds of subject's age, education level, level of interest in meditation, father's education level, and father's annual income were controlled for using analysis of covariance and stepwise regression. The results replicate the findings of previous longitudinal studies on intelligence test scores at MIU, and indicate that participation in the MIU curriculum results in improvements in measures related to general intelligence.

The relationships between nonverbal intelligence and the strength of left-hand preference in left-handers to sex and familial sinistrality.

The relationship between the strength of left-handedness and spatial reasoning ability was studied in left-handed male and female subjects with and without familial sinistrality (FS). The degree of left-handedness was assessed by the Edinburgh Handedness Inventory. The spatial reasoning ability was measured by Cattell's Culture Fair Intelligence Test. It was found that there was a negative linear correlation between nonverbal IQ and the strength of left-handedness in females with and without FS, a quadratic relationship in male left-handers without FS and a positive linear correlation in male left-handers with FS. These results indicate that the brain may exhibit different patterns of cerebral organization in left-handers to sex and FS. It was concluded that the "crowding" hypothesis may apply only to a subgroup of left-handers, i.e., females with a greater bilaterality of cognitive functions than males.