Age and sex differences in reaction time in adulthood: results from the United Kingdom Health and Lifestyle Survey

Reaction times (RTs) slow and become more variable with age. Research samples are typically small, biased, and of restricted age range. Consequently, little is known about the precise pattern of change, whereas evidence for sex differences is equivocal. The authors reanalyzed data for 7,130 adult participants in the United Kingdom Health and Lifestyle Survey, originally reported by F. A. Huppert (1987). The authors modeled the age differences in simple and 4-choice reaction time means and variabilities and tested for sex differences. Simple RT shows little slowing until around 50, whereas choice RT slows throughout the adult age range. The aging of choice RT variability is a function of its mean and the error rate. There are significant sex differences, most notably for choice RT variability.     

Skull size and intelligence, and King Robert Bruce's IQ

An estimate of someone's IQ is a potentially informative personal datum. This study examines the association between external skull measurements and IQ scores, and uses the resulting regression equation to provide an estimate of the IQ of King Robert I of Scotland (Robert Bruce, 1274–1329). Participants were 48 relatively healthy Caucasian men (age 71–76 years) resident in Scotland. Using magnetic resonance imaging data, intracranial volume estimated from external skull length and width correlated greater than .5 (p < .001) with measured intracranial area, which correlates very highly with brain volume. IQ scores estimated from the National Adult Reading Test (NART) correlated .56 (p < .001) with measured intracranial area, and .49 (p < .01) with estimated intracranial volume based on external skull width and length. The partial correlation coefficient of this latter association was .25 (p = .09) after adjustment for measured intracranial area. Thus, actual intracranial area accounts for about 74% of the variance shared by NART and estimated intracranial volume. A cast of the skull of Robert Bruce was measured and its intracranial volume estimated. A regression equation between IQ and estimated intracranial volume, based on data from the 48 subjects, estimated the IQ of Robert Bruce at about 128 (95% confidence interval 106 to  130), i.e. almost two standard deviations above the mean. NART scores show a ceiling effect, so this estimated IQ might be an underestimate. Robert Bruce's estimated high IQ is congruent with his military, political and other intellectual achievements.     

Sex differences in reaction time mean and intraindividual variability across the life span

Men are often found to have faster and less variable reaction times (RTs) than do women. However, it has not been established whether these differences occur in children. One suggestion is that sex differences in RT variability may be due to the effect of sex hormones on the brain and, by implication, may be expected in adults but not in children. The present study investigates sex differences in RT mean and intraindividual variability in a sample that includes both children and adults (age range = 4-75 years). Mean and intraindividual variability of simple RT (SRT) and 4-choice RT (CRT) were measured in 1,994 visitors to science festivals held in Edinburgh, Scotland, in 2008 and 2009 and in Cheltenham and Cambridge, England, in 2008. The commonly reported pattern of decreasing RT mean and variability in childhood and adolescence, followed by an increase in mean and variability through adulthood and into old age, was confirmed. Greater intraindividual variability for females in SRT and CRT was observed in adults but not in children. Males had significantly faster mean SRT than did females across the life span, but there were no sex differences in mean CRT. (PsycINFO Database Record (c) 2012 APA, all rights reserved).     

Correlates of personality trait levels and their changes in very old age: The Lothian Birth Cohort 1921

We tested the associations between individual differences in the Big Five personality traits and their changes over the ninth decade of life and levels of and changes in cognitive functioning, physical fitness, and everyday functioning. Besides mean-level changes in personality traits, there were significant individual differences in their rates of change between ages 81 and 87. The changes in the Big Five traits were not strongly intercorrelated, suggesting little common influence on personality change. Lower IQ at age 79 predicted lower Intellect and higher Extraversion, and more decline in Conscientiousness from ages 81 to 87. Also, decreases in physical fitness were associated with declines in Conscientiousness.     

Personality and perfectionism in chronic fatigue syndrome: A closer look

Objective: To test the hypothesis that people with chronic fatigue syndrome (CFS) would differ significantly from a healthy control group on measures of general personality and perfectionism, specifically on measures of neuroticism and unhealthy perfectionism. Method: A total of 27 female CFS outpatients and 30 female healthy controls completed questionnaires, including the NEO Personality Inventory-Revised, the Multi-dimensional Perfectionism Scale and measures of anxiety and depression. Results: The CFS group was significantly more fatigued, anxious and depressed than healthy controls. They scored significantly higher on neuroticism and unhealthy perfectionism. Healthy and unhealthy perfectionism were positively correlated in the CFS group, but not in the control group. Conclusion: The present study confirms the link between neuroticism and fatigue and finds a link between unhealthy perfectionism and fatigue. A ‘healthy trait’, such as healthy perfectionism, when coupled with evaluative concerns is not necessarily healthy in a fatigued population. Researchers and clinicians should note the context in which apparently benign traits are expressed, and how they interact with other traits.     

A Stairway to Heaven? Structure of the Religious Involvement Inventory and Spiritual Well-Being Scale

Being religious or having spiritual beliefs has been linked to improved health and well-being in several empirical studies. Potential underlying mechanisms can be suggested by psychometrically reliable and valid indices. Two self-report measures of religiosity/spirituality were completed by a cohort of older adults: the Religious Involvement Inventory and the Spiritual Well-being Scale. Both were analyzed using principal components analysis and the Mokken scaling procedure. The latter technique examines whether items can be described as having a hierarchical structure. The results across techniques were comparable and hierarchical structures were discovered in the scales. Analysis of the hierarchy in the RII items suggested the latent trait assesses the extent to which an individual’s belief in God influences their life. Examining scales with a range of psychometric techniques may give a better indication of the latent construct being assessed, particularly the hierarchies within these which may be of interest to those investigating religiosity-health associations.     

Reply to: A comment on and : How to investigate whether personality items form a hierarchical scale?

We reply to the comment by Meijer (2009) on our recent papers investigating the hierarchical properties of personality scale items. We conclude that Mokken scaling is an appropriate method for investigating the existence of hierarchical scales in general and, specifically, addresses the issue of invariant item ordering in polychotomous data.     

Intelligence and persisting with medication for two years: Analysis in a randomised controlled trial

The study examined whether verbal intelligence is associated with persisting to take medication for up to two years. The design is a prospective follow-up of compliance with taking medication in high-risk individuals participating in a randomised, placebo-controlled trial set in Central Scotland. Participants were 1993 people aged between 50 and 77 years with an ankle brachial index ≤ 0.95. The medication was 100 mg aspirin or placebo daily.The principal outcome measure was continuing with taking medication or stopping it due to having ‘changed one's mind’. Higher verbal intelligence was associated with a greater likelihood of continuing to take medication up to two years after randomisation. For a standard deviation increase in Mill Hill Vocabulary Scale score, risk of stopping medication in the first two years of the study was 0.75 (95% CI 0.64 to 0.87, p < 0.001). Comparing the highest and lowest quartiles of IQ, the lowest IQ group's relative rate of stopping medication was 2.51 (95% CI 1.52 to 4.22). The effect was not attenuated after adjustment for sex, smoking, or level of deprivation. Verbal intelligence is associated with continuing, medium-to-long term engagement with health self-care, even in the face of uncertainty about whether active treatment is being received, whether the treatment is known to be effective in general, and whether it will be helpful to the individual taking it. Such persisting with potentially helpful health behaviours in the face of uncertainty might partly explain why people with higher intelligence live longer and suffer less morbidity from chronic diseases.     

Is there still a cognitive cost of being a twin in the UK?

ObjectiveTo investigate whether twins still perform below singletons in cognitive ability tests and in national educational attainment examinations in a recent UK cohort of 11-year-olds.DesignPopulation-based cohort study, using a validated method of twin extraction.SettingEnglish state schools.Participants178,599 pupils (mean age 11 years) attending English state schools in 2004, representing 93% of local educational authorities.Main outcome measuresVerbal, quantitative and nonverbal reasoning measured by the Cognitive Abilities Test — Third Edition (CAT3), and educational attainment in English, maths and science from Key Stage 2 national curriculum tests.ResultsTwin-singleton differences in cognitive ability were of negligible effect size. Mean performance of twins was 1% of a SD below singletons on general cognitive ability, 3% lower on verbal reasoning, and less than 1% of a SD lower on quantitative and nonverbal reasoning, with and without adjustment for sex. Almost identical proportions of twins and singletons attained the expected standards of educational performance in English (80.4% versus 80.5%, respectively), maths (77.4% versus 77.3%), and science (90.1% versus 88.8%). There were no differences in rates of twins and singletons achieving higher or lower performance levels.ConclusionThe cognitive cost of being a twin reported in previous cohorts of UK children no longer exists in a large, contemporary and population-representative sample.     

Childhood intelligence,locus of control and behaviour disturbance as determinants of intergenerational social mobility: British Cohort Study 1970

Determinants of intergenerational social mobility were examined in 8287 men from the British Cohort Study 1970. Confirming previous research, parental social class, childhood intelligence, and educational qualifications were the strongest predictors of occupational social class at the age of 30. Locus of control and childhood behaviour disturbance had independent significant effects and accounted for additional amounts of variance. Self-esteem had only a trivial influence on social mobility. Structural equation modelling using full information maximum likelihood estimation demonstrated that: educational qualifications mediated other predictors' effects, accounting for the greatest amount of variance in people's own social status attainment; there was a substantial overlap of childhood behavioural disturbance, intelligence, and locus of control; there were effects of parental social class on own occupational social class attainment. Intergenerational social mobility is determined by a nexus of inter-correlated variables whose independent effects remain difficult to disentangle.