The synergy of working memory and inhibitory control: behavioral, pharmacological and neural functional evidences

Concomitant deficits in working memory and behavioral inhibition in several psychiatric disorders like attention-deficit/hyperactivity disorder, addiction or mania, suggest that common brain mechanisms may underlie their etiologies. Based on the theoretical assumption that a continuum exists between health and mental disorders, we explored the relationship between working memory and inhibition in healthy individuals, through spontaneous inter individual differences in behavior, and tested the hypothesis of a functional link through the fronto-striatal dopaminergic system. Rats were classified into three groups, showing good, intermediate and poor working memory and were compared for their inhibitory abilities. These two functions were simultaneously modulated by a dose-effect of d-amphetamine and in situ hybridization was used to quantify dopaminergic receptor (RD1) mRNAs in prefrontal cortex and striatal areas. A functional relationship between working memory and inhibition abilities was revealed. Both functions were similarly modulated by d-amphetamine according to an inverted-U shaped relationship and depending on initial individual performances. D-amphetamine selectively improved working memory and inhibition of poor and intermediate performers at low doses whereas it impaired both processes in good performers at a higher dose. D1 receptors were less expressed in prelimbic, infralimbic and anterior cingulate cortices of good compared to intermediate and poor performers, whereas no difference was observed between groups in striatal areas. The synergy of working memory and inhibitory abilities, observed in both healthy and psychiatric populations, may originate from endogenous variability in dopaminergic prefrontal cortex activity. Such findings confirm the validity of a dimensional approach, based on the concept of continuity between health and mental disorders for identifying endophenotypes of mental disorders.     

How do people judge risks: Availability heuristic, affect heuristic, or both?

How does the public reckon which risks to be concerned about? The availability heuristic and the affect heuristic are key accounts of how laypeople judge risks. Yet, these two accounts have never been systematically tested against each other, nor have their predictive powers been examined across different measures of the public's risk perception. In two studies, we gauged risk perception in student samples by employing three measures (frequency, value of a statistical life, and perceived risk) and by using a homogeneous (cancer) and a classic set of heterogeneous causes of death. Based on these judgments of risk, we tested precise models of the availability heuristic and the affect heuristic and different definitions of availability and affect. Overall, availability-by-recall, a heuristic that exploits people's direct experience of occurrences of risks in their social network, conformed to people's responses best. We also found direct experience to carry a high degree of ecological validity (and one that clearly surpasses that of affective information). However, the relative impact of affective information (as compared to availability) proved more pronounced in value-of-a-statistical-life and perceived-risk judgments than in risk-frequency judgments. Encounters with risks in the media, in contrast, played a negligible role in people's judgments. Going beyond the assumption of exclusive reliance on either availability or affect, we also found evidence for mechanisms that combine both, either sequentially or in a composite fashion. We conclude with a discussion of policy implications of our results, including how to foster people's risk calibration and the success of education campaigns. (PsycINFO Database Record (c) 2012 APA, all rights reserved).     

A mixed model approach to meta-analysis of diagnostic studies with binary test outcome

We propose 2 related models for the meta-analysis of diagnostic tests. Both models are based on the bivariate normal distribution for transformed sensitivities and false-positive rates. Instead of using the logit as a transformation for these proportions, we employ the tα family of transformations that contains the log, logit, and (approximately) the complementary log. A likelihood ratio test for the cutoff value problem is developed, and summary receiver operating characteristic (SROC) curves are discussed. Worked examples showcase the methodology. We compare the models to the hierarchical SROC model, which in contrast employs a logit transformation. Data from various meta-analyses are reanalyzed, and the reanalysis indicates a better performance of the models based on the tα transformation. (PsycINFO Database Record (c) 2012 APA, all rights reserved).     

Eye movements of second language learners when reading spaced and unspaced Chinese text

The effect of spacing in relation to word segmentation was examined for four groups of non-native Chinese speakers (American, Korean, Japanese, and Thai) who were learning Chinese as second language. Chinese sentences with four types of spacing information were used: unspaced text, word-spaced text, character-spaced text, and nonword-spaced text. Also, participants' native languages were different in terms of their basic characteristics: English and Korean are spaced, whereas the other two are unspaced; Japanese is character based whereas the other three are alphabetic. Thus, we assessed whether any spacing effects were modulated by native language characteristics. Eye movement measures showed least disruption to reading for word-spaced text and longer reading times for unspaced than character-spaced text, with nonword-spaced text yielding the most disruption. These effects were uninfluenced by native language (though reading times differed between groups as a result of Chinese reading experience). Demarcation of word boundaries through spacing reduces non-native readers' uncertainty about the characters that constitute a word, thereby speeding lexical identification, and in turn, reading. More generally, the results indicate that words have psychological reality for those who are learning to read Chinese as a second language, and that segmentation of text into words is more beneficial to successful comprehension than is separating individual Chinese characters with spaces.     

Cultural variation in the social organization of problem solving among African American and European American siblings

This study examined the social organization of a problem-solving task among 15 African American and 15 European American sibling pairs. The 30 sibling pairs between the ages of 6 and 12 were video recorded constructing a marble track together during a home visit. African American siblings were observed to collaborate more often than European American siblings who were more likely to divide up the labor and direct each other in constructing the marble track. In addition, older European American siblings made more proposals of step plans than older African American siblings. The findings provide insights into the cultural basis of the social organization of problem solving across African American and European American siblings.     

Factor structure and item analysis of the yale food addiction scale in obese candidates for bariatric surgery

Converging research suggests phenomenological and neurobiological similarities between excessive food consumption and addictive behaviour in substance dependence. Recently, the Yale Food Addiction Scale (YFAS) has been proposed for the assessment of addictive eating behaviour. The German version of the YFAS was administered to obese individuals seeking bariatric surgery (N?=?96). Factor structure, internal consistency, and item statistics were analysed. Forty participants (41.70%) received a food addiction diagnosis. The one-factorial structure of the YFAS, which has been found in non-clinical samples, could be confirmed. All but three items had factor loadings >.50. Internal consistency was α?=?.82. Item analysis revealed that items related to unsuccessful attempts to cut down and consumption despite physical and emotional problems were endorsed by the majority of participants. Findings support the use of the YFAS in clinical populations, while applicability of some items differs between clinical and non-clinical samples. Copyright ? 2012 John Wiley & Sons, Ltd and Eating Disorders Association.     

The impact of self-reported pubertal status and pubertal timing on disordered eating in irish adolescents

This paper considers the impact of pubertal status and pubertal timing on disordered eating in Irish adolescents. 1190 boys and 1841 girls completed the Eating Attitudes Test-26, the Eating Disorder Inventory-III and self-report measures of pubertal status and pubertal timing. Regarding pubertal status, greater maturity in girls was associated with increased overall eating concerns, higher drive for thinness and higher levels of body dissatisfaction. In boys, greater maturity was associated with lower drive for thinness and lower body dissatisfaction. Regarding pubertal timing, early-maturing girls showed the most eating concerns, the highest drive for thinness, scored highest on bulimic symptoms and were the most dissatisfied with their bodies. In contrast, late-maturing boys had more bulimic symptoms and more dissatisfaction with their bodies than on-time peers. The findings suggest that puberty itself is a risk factor for disordered eating for girls rather than boys; however, pubertal timing is a risk factor for both. Copyright ? 2012 John Wiley & Sons, Ltd and Eating Disorders Association.     

Acoustic markers associated with impairment in language processing in Alzheimer's Disease

This study broaches in a novel way the analysis of cognitive impairment characteristic of the early stages of Alzheimer's Disease (AD). Specifically, we attempt to determine the acoustic speech parameters that are sensitive to the onset of the disease, and their association with the language deficit characteristic of AD. Speech analysis was carried out on 21 elderly patients with AD using Praat software, which analyzes the acoustic components of speech. The data obtained were subjected to stepwise regression, using the overall scores obtained in the test as the criterion variable, and the scores on the frequency, amplitude and periodicity variables as predictors of performance. We found that the percentage of voiceless segments explains a significant portion of the variance in the overall scores obtained in the neuropsychological test. This component seems to be related mainly to the patient's ability in phonological fluency. This finding could permit the creation of a diagnostic test for AD through analysis of the acoustic speech parameters at very low cost in terms of both time and resources.