Intra-individual reaction time variability in schizophrenia, depression and borderline personality disorder

Intra-individual reaction time variability (IIV) in neuropsychological task performance reflects short term fluctuations in performance. Increased IIV has been reported in patients with schizophrenia and could be related to a deficient neural timing mechanism, but the role of IIV in adult patients with other psychiatric disorders has not been established. Therefore, we compared IIV measures obtained in a Go/Nogo task from patients with schizophrenia, major depression and borderline personality disorder. IIV was increased for patients with schizophrenia. When correcting for differences in mean reaction time, depressive and borderline patients also showed increased IIV. Importantly, all groups showed a strong association between IIV and accuracy of task performance. This suggests that increased IIV might be a sensitive marker for the efficiency of top-down attentional control in all diagnostic groups. Aside from these similarities, the complete results including measures of IIV, mean reaction time and accuracy show differential patterns for patients with schizophrenia compared to those with borderline personality disorder or depression. These results are discussed with respect to common versus disorder-specific neural mechanisms underlying increased IIV.     

The effect of spectral difference on auditory saltation

Auditory saltation is a spatiotemporal illusion in which the judged positions of sound stimuli are shifted toward subsequent stimuli that follow closely in time and space. In this study, the "reduced-rabbit" paradigm and a direct-location method were employed to investigate the effect of spectral sound content on the saltation illusion. Eighteen listeners were presented with sound sequences consisting of three high-pass or low-pass filtered noise bursts. Noise bursts within a sequence were either the same or differed in frequency. Listeners judged the position of the second sound using a hand pointer. When the time interval between the second and third sound was short, the target was shifted toward the location of the subsequent stimulus. This displacement effect did not depend on the spectral content of the first sound, but decreased substantially when the second and third sounds were different. The results indicated an effect of spectral difference on saltation that is discussed with regard to a recently proposed stimulus integration approach in which saltation was attributed to an interaction between perceptual processing of temporally proximate stimuli.     

Impulsive and callous traits are more strongly associated with delinquent behavior in higher risk neighborhoods among boys and girls

The purpose of the present study was to determine whether the effect of impulsive and callous personality traits on delinquent behavior varied across neighborhood context in a population-based, statewide sample of 85,000 Iowa schoolchildren ages 10-19. Two previous studies examining the association between impulsivity and delinquency across disadvantaged and affluent neighborhoods have yielded contrasting findings. Results of the present study suggested a robust moderating effect of neighborhood context on personality risk for delinquency. The relation between impulsivity and delinquency was greater in neighborhoods low in collective efficacy compared to neighborhoods high in collective efficacy. A similar interaction was found for callous personality traits, indicating the consistency of the moderating effect of neighborhood context on personality risk for delinquency. Gender differences were also examined, and results were replicated in a holdout sample.     

Audiovisual influences on the perception of visual apparent motion: exploring the effect of a single sound

Previous research has shown that irrelevant sounds can facilitate the perception of visual apparent motion. Here the effectiveness of a single sound to facilitate motion perception was investigated in three experiments. Observers were presented with two discrete lights temporally separated by stimulus onset asynchronies from 0 to 350 ms. After each trial, observers classified their impression of the stimuli using a categorisation system. A short sound presented temporally (and spatially) midway between the lights facilitated the impression of motion relative to baseline (lights without sound), whereas a sound presented either before the first or after the second light or simultaneously with the lights did not affect motion impression. The facilitation effect also occurred with sound presented far from the visual display, as well as with continuous-sound that was started with the first light and terminated with the second light. No facilitation of visual motion perception occurred if the sound was part of a tone sequence that allowed for intramodal perceptual grouping of the auditory stimuli prior to the critical audiovisual stimuli. Taken together, the findings are consistent with a low-level audiovisual integration approach in which the perceptual system merges temporally proximate sound and light stimuli, thereby provoking the impression of a single multimodal moving object.     

Psychosomatische Aspekte des Diabetes mellitus

The term “diabetes mellitus” describes a group of endocrinological diseases characterised by hyperglycemia. The treatment is demanding for patients in terms of self-management and self-responsibility, and some patients need not only medical but psychological support as well. This article reviews essential psychological aspects of diabetes, starting with factors affecting adherence to diabetes treatment. The main part describes epidemiology and interactions between anxiety disorders, eating disorders and depression in patients with diabetes. Treatment recommendations are derived from current knowledge in accordance with evidence-based treatment guidelines.     

Forgetting in immediate serial recall: decay, temporal distinctiveness, or interference?

Three hypotheses of forgetting from immediate memory were tested: time-based decay, decreasing temporal distinctiveness, and interference. The hypotheses were represented by 3 models of serial recall: the primacy model, the SIMPLE (scale-independent memory, perception, and learning) model, and the SOB (serial order in a box) model, respectively. The models were fit to 2 experiments investigating the effect of filled delays between items at encoding or at recall. Short delays between items, filled with articulatory suppression, led to massive impairment of memory relative to a no-delay baseline. Extending the delays had little additional effect, suggesting that the passage of time alone does not cause forgetting. Adding a choice reaction task in the delay periods to block attention-based rehearsal did not change these results. The interference-based SOB fit the data best; the primacy model overpredicted the effect of lengthening delays, and SIMPLE was unable to explain the effect of delays at encoding. The authors conclude that purely temporal views of forgetting are inadequate.     

Risk factors for addictive disorders: a discriminant analysis on 374 addicted and 513 nonpsychiatric participants

Many common risk factors have been described in addictive disorders. Little is known about factors' respective contributions to discrimination of addicted and nonaddicted participants. Two large samples were compared including 513 nonpsychiatric participants and 374 addicted participants meeting the DSM-IV criteria for eating disorders, alcohol, or substance dependence. Twenty-six risk factors were assessed by interview or self-rating scales. A discriminant analysis determined the respective weight of each risk factor. One discriminant function emerged and characterized a depressive dimension. The results suggest that the different risk factors described in addiction could be related to a depressive dimension.     

School achievement strongly predicts midlife IQ

The relationship between measures of IQ and standardized school achievement tests is well established at around r ≈ 0.5 when the two are measured in close proximity. The current paper examined the stability of this correlation when comparing elementary school achievement (grades 3–8) and midlife IQ. Iowa Adoption Study participants who had standardized school achievement measures (ITBS) on file were given the WAIS-III. Mean age at IQ testing was 44.01 years (SD 6.65 years). The correlation between school achievement and WAIS-III FSIQ was r = 0.64, suggesting substantial life span stability in this relationship. Furthermore, elementary school achievement was substantially correlated with occupational status and household income at midlife. These findings suggest that standardized school achievement data is a useful measure of premorbid IQ.     

Iterated learning: Intergenerational knowledge transmission reveals inductive biases

Cultural transmission of information plays a central role in shaping human knowledge. Some of the most complex knowledge that people acquire, such as languages or cultural norms, can only be learned from other people, who themselves learned from previous generations. The prevalence of this process of “iterated learning” as a mode of cultural transmission raises the question of how it affects the information being transmitted. Analyses of iterated learning utilizing the assumption that the learners are Bayesian agents predict that this process should converge to an equilibrium that reflects the inductive biases of the learners. An experiment in iterated function learning with human participants confirmed this prediction, providing insight into the consequences of intergenerational knowledge transmission and a method for discovering the inductive biases that guide human inferences.     

Knowledge alters visual contrast sensitivity

Research has shown that the visual system’s sensitivity to variations in luminance (visual contrast) within a particular area of the retina is affected in a bottom-up fashion by the ambient contrast levels in nearby regions. Specifically, changes in the ambient contrast in areas surrounding the target area alter the sensitivity to visual contrast within the target area. More recent research has shown that paying attention to the target or target area modulates contrast sensitivity, suggesting a top-down influence over contrast sensitivity that is mediated by attention. Here we report another form of top-down influence over contrast sensitivity that is unlikely to be mediated by attention. In particular, we show that knowledge and/or expectations about the levels of visual contrast that may appear in upcoming targets also affect how sensitive the observer is to the contrast in the target. This sort of knowledge-driven, top-down contrast sensitivity control could be used to preset the visual system’s contrast sensitivity to maximize discriminability and to protect contrast-sensitive processes from a contrast overload. Overall, our results suggest that existing models of contrast sensitivity might benefit from the inclusion of top-down control mechanisms.