Vincent Egan

Intelligence and the differentiation hypothesis

Abstract General intelligence (Spearmans g ) accounts for over 50% of the reliable variance in a battery of mental tests in a sample of the general population. In a “differentiation hypothesis” originally suggested by Spearman it is hypothesized that the degree to which g pervades performance on mental tests is greater at lower ability levels. In addition to providing a critical review, the study presented here tests the differentiation hypothesis: (a) at different ability levels and ages; (b) when groups are selected on the basis of a wide range of criterion abilities; and (c) by developing new statistical techniques for sampling groups of different ability levels. Data used were the Differential Aptitude Test results of over 10,500 Irish schoolchildren aged 14 through 17 years. Of groups selected on the basis of verbal, numerical, or spatial ability, the below-average ability groups had a more pervasive g factor, confirming the differentiation hypothesis.

The NEO-FFI : emerging British norms and an item-level analysis suggest N, A and C are more reliable than O and E

Abstract The NEO Five Factor Inventory (NEO-FFI) was given to 1025 British subjects as part of three independent research studies. Data from these studies were pooled and subjected to item-level analyses. Using standard scoring criteria from the measure provisional British norms were produced which were broadly equivalent to those obtained in the USA. The individual subscales showed good internal consistency. However, the item-level principal components analysis using varimax and oblique rotation and confirmatory factor analysis revealed that only the Neuroticism, Agreeableness and Conscientiousness traits were coherently represented in the main factors derived by the analysis. Openness and Extraversion factors did not show such stability or consistency. It is argued that as a result of these difficulties, thoughtlessly embracing the NEO-FFI as a quick and efficient instrument for measuring the ‘Big Five’ personality traits is perhaps premature, as the instrument requires modification and improvement before it can truly be regarded as measuring five independent personality traits.

Size isn't everything: A study of brain volume, intelligence and auditory evoked potentials

Abstract Although brain volumes calculated from magnetic resonance (MR) imaging have been found to correlate with IQ, the relationship between MR-derived brain volume and other mental processes has not been examined. Fifty normal-ability adults had their brain volume calculated using MR scanning, along with tasks measuring IQ, memory, and information-processing speed, and an auditory evoked potential (AEP) task. All MR scans were corrected for artefacts arising from inhomogenous coil response. Of the three AEP components measured, only P3 latency and amplitude were associated with measures of mental ability. Out of the 50 adults tested, 40 had usable MR records. Corrected for height and weight, total brain volume was associated with Full-Scale IQ (r = 0.32, P

Visual and auditory inspection time: Their interrelationship and correlations with IQ in high ability subjects.

Abstract Results from three visual inspection time (IT) tests and a new auditory IT test were correlated with psychometric measures of intelligence in an undergraduate population. The four IT tests correlated with each other at similar levels to the psychometric test intercorrelations. The range of raw IQ-IT correlations agreed with the predicted -0.35 that has been reported previously. Corrected correlations indicated that the true IQ-IT correlation is in the region of -0.55. This study corroborates the hypothesis that a substantial proportion of the IQ variance is located in individual differences in perceptual intake speed, both visual and auditory. The intercorrelation of the auditory and visual IT Tests indicates that IT is, in part, due to differences in nervous system functioning in general. The results do not support a specific strategy theory of IT performance.

Personality traits, personality disorders and sensational interests in mentally disordered offenders

Purpose. Sensational interests (e.g. an interest in the occult or the methods of violence) in mentally disordered offenders are claimed to signify greater risk of psychopathology, but evidence to support this view is slight. Methods. The relationships between self-reported DSM-IV personality disorder (PD), general personality traits and sensational interests were examined in 155 of 167 consecutively referred offenders to a forensic psychology service. The subscales of the PD and personality trait measures were reduced to the four basic PD/trait dimensions (asocial, antisocial, anxious and anankastic) using cone rmatory factor analysis. Results. Those high on the ‘ antisocial’ factor (which was primarily dee ned by low Agreeableness, low Conscientiousness, and substantial elements of Paranoid, Antisocial and Borderline PD) were more interested in ‘ violent-occult’ and militaristic topics. Conclusions. The aspects of the antisocial factor primarily associated with an interest in sensational and potentially violent topics cover a wide range of putative disorders. However, the factors ree ecting asocial, anxious or anankastic disorders do not show a reliable association with measures of sensational interests. These results suggest that the personality dimensions ree ecting an interest in ‘ sensational’ topics in mentally disordered offenders are relatively specie c.

PASAT: Observed correlations with IQ

Relations between psychometric measures of intelligence and the clinical Paced Auditory Serial-Addition Task (PASAT) were examined in a non-clinical group of young adults. PASAT correlated with the six separate psychometric scales, and especially with an overall estimate of non-verbal intelligence (r = 0.71, P < 0.001). One-minute samples of PASAT performance were also strongly correlated with intelligence (median r = 0.62, P < 0.01). The results suggest that PASAT is correlated with general intelligence and numerical ability, contrary to previous claims.

Is social dominance a sex-specific strategy for infidelity?

The current study investigated personality, psychopathy and mating effort of 84 adults recruited from a large office setting who admitted infidelity whilst involved in another relationship. These were compared with individuals who had not been unfaithful. Measurement scales were reduced by principal components analysis to three general factors; social dominance, manipulativeness, and openness. There was no sex difference in social dominance or openness. Males were higher on the manipulativeness factor. There were no differences in the social dominance or openness factors for individuals admitting affairs compared to those who had not; males who admitted affairs were higher in social dominance. There was an interaction between sex and having had an affair (or not) for the social dominance, this indicated males who had committed infidelity were higher on the social dominance dimension than females who were also unfaithful, the reverse was the case for males and females who had not had affairs. Manipulativeness predicted the number of affairs had and their emphasis on sexuality, whereas social dominance did not. These results suggest male and female infidelity is underpinned by differential personality types as well as differential sexual strategies.

The Edinburgh cohort of Hiv-positive drug users: current intellectual function is impaired, but not due to early Aids dementia complex

Eighty people, all infected by HIV-contaminated drug injection equipment between 1983 and 1984, completed the National Adult Reading Test (NART) and selected revised Wechsler Adult Intelligence Scale (WAIS-R) subtests. Demographic variables (age, sex, years of education, and social class) were recorded as additional indices of premorbid functioning. Cross-sectional comparison of NART and WAIS-R scores showed that cognitive function was not more impaired with increasing severity of HIV illness, as defined by clinical staging. Nor were HIV-positive patients more impaired than a control group of seronegative drug users. Mean NART scores did not differ significantly from that predicted by a regression model, indicating that the NART can be reliably used to estimate premorbid intelligence for this population. However, current performance on WAIS-R subtests was below that expected from population models of cognitive function that combine measures of premorbid IQ and demographic factors, providing evidence of impaired intellectual function. Currently observed cognitive deficits are probably more due to drug use than to the insidious onset of AIDS dementia complex.

Sexual offenders against children: the influence of personality and obsessionality on cognitive distortions.

Sexual offenders against children are generally inadequate in their social functioning and diverse in their psychopathology. The degree to which this inadequate functioning and psychopathology influences therapeutic interventions brings into question the belief that generic non clinical programmatic treatment work is always appropriate for such a cohort. The Sex Offenders Assessment Package (SOAP) measures inadequate social functioning and sexual deviance, but has not been linked to broader individual differences and generic psychopathology. We collected information examining the relationship between the SOAP and standard measures of personality (the NEO-FFI) and obsessive-compulsiveness (MOCI) in a sample of 200 sexual offenders against children seen by the Probation Service. Factor analysis was used to reduce the SOAP to three reliable factors: emotional distress, cognitions supporting sex with children, and concern for others. These factors correlated respectively with higher Neuroticism and lower Extroversion; greater obsessive-compulsiveness on the MOCI, and trait Agreeableness, irrespective of whether or not one corrected for socially desirable responding. When partial correlation controlled for the influence of Neuroticism on the correlation between cognitions supporting sex with children and the MOCI, there was no change in the association between these variables. These results show that negative affect and obsessional tendencies are important underlying influences on the feelings and behavior of sexual offenders, that the obsessionality of the group is not attributable to Neuroticism, and suggest useful additional foci to enhance the treatment of this diverse clinical group.

The relationship between social problem-solving and personality in mentally disordered offenders

Poor social problem-solving skills may account for some criminal behaviours in mentally disordered offenders, and social problem-solving may be mediated by personality traits. We examined the relationship between personality and social problem-solving in 52 mentally disordered offenders, (38 mentally ill and 14 personality disordered) detained in a regional secure unit. Since t-tests indicated no differences between the mentally ill and personality disordered groups, they were pooled into a single sample. Correlations indicated that high neuroticism (N) was related to poor social problem-solving, and high scores on the other five-factor traits were related to good social problem-solving. High N, which is a core feature of personality disorders as well as being a common feature of offenders, may signal emotional reactivity which militates against effective social problem-solving. N is, however, negatively correlated with extraversion (E), conscientiousness (C), and agreeableness (A), therefore partial correlations were conducted controlling for N. Once N is discounted, the main trait associated with problem-solving is openness (O), which is positively related to problem-solving, perhaps due to the relationship of O to intelligence and creativity. A positive correlation between E and a more positive problem orientation remains, perhaps because optimism is a defining feature of high E.