Modeling the effects of hypoglycemia on a two-choice task in adult humans.

Objective: Previous research has demonstrated that hypoglycemia causes reaction times to be slower and more variable. Reaction time tests, however, use multiple cognitive and noncognitive processes. This study is the first to use a validated sequential sampling model (diffusion model) applied to results obtained from a simple 2-choice task in adult humans to assess the effects of hypoglycemia on the basic parameters of decision making. Method: Fourteen adult volunteers were tested on a numerosity discrimination task with and without reduced blood glucose concentrations. The results were analyzed with a model that dissects the components of processing that underlie decisions: the quality of the information on which a decision is based (drift rate), the critical amount of evidence that must be accumulated before a decision is made (boundary separation), and the time taken by nondecision processes. Results: Hypoglycemia resulted in a reduction of mean drift rate from 0.290 to 0.211, t(13) = 4.10, p     

Effect of acute hypoglycemia on visual information processing in adults with type 1 diabetes mellitus

Acute hypoglycemia in people with type 1 (insulin-dependent) diabetes mellitus causes general impairment in cognitive performance. The effects on more specific cognitive processes are less well defined. Acute hypoglycemia has been shown to impair visual information processing in nondiabetic human subjects and has now been examined in 16 adult subjects with type 1 diabetes. All subjects had normal visual acuity and no diabetic retinopathy, and their median (range) age was 24 (18-47) years with a median (range) duration of type 1 diabetes of 8 (2-18) years and a mean (SD) HbA1c of 8.5 (1.3)%. A hyperinsulinemic glucose clamp technique was used to maintain arterialized blood glucose at 5.0 mmol l(-1), and on separate test days, either euglycemia was continued or hypoglycemia (2.6 mmol l(-1)) was induced. During each condition subjects performed tests of visual processing and cognitive function. Hypoglycemia caused a significant disruption in general cognitive ability as assessed by digit symbol (p < 0.001) and trail-making B (p < 0.05) tasks. Conventional measures of visual acuity were unaffected by hypoglycemia, but visual information processing deteriorated significantly as indexed by inspection time (p < 0.005) and visual change detection (p < 0.01). Contrast sensitivity tended to deteriorate during hypoglycemia (p = 0.06). In conclusion, hypoglycemia impairs important aspects of early visual information processing and contrast sensitivity in adults with type 1 diabetes. Further research is needed to evaluate the functional relevance of such changes for everyday tasks that require the intake of visual information at speed and under conditions of low contrast.     

PASAT performance and the pattern of uptake of 99mTc-exametazime in brain estimated with single photon emission tomography

The effect of the paced auditory serial addition test (PASAT) on the regional uptake of 99mTc-exametazime was determined by single photon emission computed tomography. Twenty insulin-treated diabetic outpatients were scanned at rest and during the performance of the PASAT task using split-dose injection of tracer. When resting and activation scans were compared there were significant decreases in tracer uptake in the right anterior cingulate and left posterior cingulate areas during PASAT activation. The findings are compared with previous studies which had implicated the anterior cingulate area in the mechanisms of attention in humans and other animals. The potentially confounding role of anxiety during attentional tasks is discussed.     

A (latent) Big Five personality model in 1915? A reanalysis of Webb's data.

In 1915 Edward Webb, working under Charles Spearman at University College London, reported a study of personality trait ratings of 194 trainee teachers. The original report found a single personality factor, which Webb named Persistence of Motives or w. Subsequent partial reanalyses and reinterpretations of Webb's data are reviewed and are found to be misleading. The quality of Webb's data is high; 2 raters assessed every student, and the raters' studies of the students' characters were unusually prolonged and intense. A new reanalysis of Webb's data analyzes 6- and 5-factor personality structures latent in the data set, which are judged by experts to be congruent with current 5-factor and other models of human personality trait structure. Therefore, the first, albeit latent, discovery of some currently recognized broad personality dimensions came from the department that is the birthplace of differential psychology. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Alcohol intake and cognitive abilities in old age: The Lothian Birth Cohort 1936 study.

Objective: Moderate alcohol consumption has been associated with better cognitive performance in late adulthood, possibly by improving vascular health. Few studies have examined the potentially confounding roles of prior cognitive ability and social class in this relationship. Method: Participants were 922 healthy adults about 70 years old in the Lothian Birth Cohort 1936 study, for whom there are IQ data from age 11. Alcohol consumption was obtained by self-report questionnaire. Cognitive outcome measures included general cognitive ability, speed of information processing, memory, and verbal ability. Results: Moderate to substantial drinking (>2 units/day) was associated with better performance on cognitive tests than low-level drinking (≤2 units/day) or nondrinking in men and women. After adjusting for childhood IQ and adult social class, most of these associations were removed or substantially attenuated. After full adjustment, a small, positive association remained between overall alcohol intake and memory (women and men) and verbal ability (women only). Women's overall alcohol intake was derived almost exclusively from wine. In men, effects differed according to beverage type: wine and sherry–port consumption was associated with better verbal ability, but beer was associated with a poorer verbal ability and spirits intake was associated with better memory. Conclusions: Prior intelligence and socioeconomic status influence both amount and type of alcohol intake and may partly explain the link between alcohol intake and improved cognitive performance at age 70. Alcohol consumption was found to make a small, independent contribution to memory performance and verbal ability, but these findings' clinical significance is uncertain. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

"Age and sex differences in reaction time in adulthood: Results from the United Kingdom Health and Lifestyle Survey": Correction.

Reports an error in "Age and sex differences in reaction time in adulthood: Results from the United Kingdom Health and Lifestyle Survey" by Geoff Der and Ian J. Deary (Psychology and Aging, 2006[Mar], Vol 21[1], 62-73). In the article, the link to supplemental material is incorrect. The correct supplemental link follows. Supplemental materials are available online at http://dx.doi.org/10.1037/0882-7974.21.1.62.supp. (The following abstract of the original article appeared in record 2006-03906-007.) 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. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Intelligence and inspection time: Achievements, prospects, and problems.

The purpose of this article is to introduce the inspection-time measure to the wider psychological community. Inspection time is, to date, the only single information-processing index that accounts for approximately 20% of intelligence-test variance. We argue that inspection time, because of its much-replicated correlation with IQ and its potential for theoretical tractability, has more potential for our understanding of individual differences in cognitive ability than other indexes of human information processing. The nature of inspection time and its measurement are described, studies correlating inspection time and IQ-type scores are summarized, and the difficulties of explaining this correlation are highlighted. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hostility, cigarette smoking and alcohol consumption in the general population

Hostility has been associated with coronary heart disease, and hostility may affect coronary risk through its influence on risk factors such as cigarette smoking and alcohol consumption. The objective of this study was to determine relationships between hostile personality, cigarette smoking and alcohol consumption in the general population. The Edinburgh Artery Study comprises a cross-sectional survey of 1592 men and women aged 55-74 years sampled from age-sex registers of 10 general practices throughout the city. The Bedford-Foulds Personality Deviance Questionnaire was used to elicit extrapunitiveness (including hostile thoughts), dominance (including hostile acts) and intropunitiveness. Social class, age and deprivation score were controlled for in multivariate analyses. The hostile thoughts scale emerged as a significant independent predictor of alcohol consumption in men and women (P < or = 0.01), and the models accounted for 4-9% of the variance in alcohol consumption. Hostile acts were independently predictive of smoking in men (P < or = 0.001), with the model accounting for 5% of the variance in smoking. Hostile thoughts were independently predictive of smoking in women (P < or = 0.001), and the model accounted for 4% of the variance in their smoking. We conclude that hostility may affect coronary risk through its influence on lifestyle-related coronary risk factors, although in future further elucidation of hostility type and standard measurement of hostility are necessary.