Order or disorder? Impaired Hebb learning in dyslexia

The present study offers an integrative account proposing that dyslexia and its various associated cognitive impairments reflect an underlying deficit in the long-term learning of serial-order information, here operationalized as Hebb repetition learning. In nondyslexic individuals, improved immediate serial recall is typically observed when one particular sequence of items is repeated across an experimental session, a phenomenon known as the Hebb repetition effect. Starting from the critical observation that individuals with dyslexia seem to be selectively impaired in cognitive tasks that involve processing of serial order, the present study is the first to test and confirm the hypothesis that the Hebb repetition effect is affected in dyslexia, even for nonverbal modalities. We present a theoretical framework in which the Hebb repetition effect is assumed to be a laboratory analogue of naturalistic word learning, on the basis of which we argue that dyslexia is characterized by an impairment of serial-order learning that affects language learning and processing.     

“You Shouldn’t Look at Us Strangely”: An Exploratory Study on Personal Perspectives on Quality of Life of Adolescents with Emotional and Behavioral Disorders in Residential Youth Care

Applied Research in Quality of Life - Adolescents with Emotional and Behavioral Disorders (EBD) have complex needs and experience challenges in various developmental areas and life domains. The...     

Major depression, double depression and personality disorders

Personality disorders are much more common among depressive patients than among normal people. Until now, little research has been conducted into the prevalence of personality disorders among patients with both major depression and dysthymia (double depression). The subject of this study is whether depressive patients with dysthymia have more personality disorders than those with no dysthymia. The Vragenlijst voor Kenmerken van de Persoonlijkheid (a Dutch self-report based on the International Personality Disorder Examination) was completed for 211 outpatients with major depression. Approximately 60% of the patients suffer from one or more personality disorders. Depressive patients with dysthymia differ little from the patients without dysthymia, but patients with dysthymia have more cluster A disorders and are more avoidant. Depressive patients without dysthymia do not differ from the patients with dysthymia in terms of symptoms. Depressive patients with personality disorders have significantly more symptoms than the patients without these disorders. There is no interaction between dysthymia and personality disorder.     

Often biased but rarely in doubt: How initial reactions to stigmatized applicants affect interviewer confidence

Building on a metacognitive framework of heuristic judgments, we investigate the effect of applicant stigma on interviewers’ overconfidence in their (biased) judgments. There were 193 experienced interviewers conducting a face-to-face interview with an applicant who was facially stigmatized or not, and who was visible (traditional interview) or not (partially blind interview), to the interviewer during the rapport-building stage. In traditional interviews, interview judgments of stigmatized applicants were negatively biased, and interviewers reported overconfidence in these judgments. This effect was partially mediated by the interviewer’s professional performance during rapport building. Interview procedure moderated both the direct and indirect effect (through professional performance) of applicant stigma on interviewer confidence. Results show that interviewer (over)confidence in biased judgments is driven by the initial effects of, and reactions to, the stigmatized applicant.     

Post‐merger identification as a function of pre‐merger identification,relative representation,and pre‐merger status

This experiment examined the impact of pre‐merger identification (low, high), pre‐merger group status (low, high) and relative representation (low, high) upon identification with a new merger group. In the first phase of the study, 156 university students were assigned to a pre‐merger team of ‘inductive’ thinkers. Pre‐merger identification was manipulated by giving the participants feedback about the extent to which they used the inductionist style. Pre‐merger status was manipulated by informing participants that their team had performed worse or better than a deductionist team on a decision‐making task. In the second phase, the two pre‐merger teams were combined into a merger team of analyst thinkers. Relative representation was manipulated by maintaining most or none of the features of the pre‐merger team in this new merger team. The results revealed that high pre‐merger identifiers identified more strongly with the merger group than did low pre‐merger identifiers, but only when the relative representation was high. Pre‐merger status did not influence post‐merger identification. Copyright © 2006 John Wiley & Sons, Ltd.     

Measuring coherence

This paper aims to contribute to our understanding of the notion of coherence by explicating in probabilistic terms, step by step, what seem to be our most basic intuitions about that notion, to wit, that coherence is a matter of hanging or fitting together, and that coherence is a matter of degree. A qualitative theory of coherence will serve as a stepping stone to formulate a set of quantitative measures of coherence, each of which seems to capture well the aforementioned intuitions. Subsequently it will be argued that one of those measures does better than the others in light of some more specific intuitions about coherence. This measure will be defended against two seemingly obvious objections.     

Tactile perception of thermal diffusivity

The thermal diffusivity of an object is a parameter that controls the rate at which heat is extracted from the hand when it touches that object. It is an important feature for distinguishing materials by means of touch. In order to quantitatively describe the ability of human observers to discriminate between materials on the basis of heat extraction rate, we conducted an experiment in which this heat extraction was performed in a controlled way. In different conditions, subjects were repeatedly asked to select from two stimuli the one that cooled faster. The discrimination threshold was around 43% of the extraction rate. A rate that was twice as slow also yielded twice the absolute threshold. When we halved the temperature difference between the beginning and end of the stimulus, the threshold did not change as much. In separate experiments, we investigated the different cues that were available in the stimulus: initial cooling rate and end temperature. Both cues were used for discrimination, but cooling rate seemed to be the most important.     

Development of trust and reciprocity in adolescence

We investigate the development of two types of prosocial behavior, trust and reciprocity, as defined using a game-theoretical task that allows investigation of real-time social interaction, among 4 age groups from 9 to 25 years. By manipulating the possible outcome alternatives, we could distinguish among important determinants of trust and reciprocity that are related to the risk and benefit of trusting. The results demonstrate age-related changes in sensitivity to outcome for others from late childhood until late adolescence, with different developmental trajectories for trust and reciprocity and differential sensitivity to risk and benefit for self and others.     

Seeing and feeling volumes: The influence of shape on volume perception

The volume of common objects can be perceived visually, haptically or by a combination of both senses. The present study shows large effects of the object's shape on volume perception within all these modalities, with an average bias of 36%. In all conditions, the volume of a tetrahedron was overestimated compared to that of a cube or a sphere, and the volume of a cube was overestimated compared to that of a sphere. Additional analyses revealed that the biases could be explained by the dependence of the volume judgment on different geometric properties. During visual volume perception, the strategies depended on the objects that were compared and they were also subject-dependent. However, analysis of the haptic and bimodal data showed more consistent results and revealed that surface area of the stimuli influenced haptic as well as bimodal volume perception. This suggests that bimodal volume perception is more influenced by haptic input than by visual information.