Individual differences in cognitive plasticity: an investigation of training curves in younger and older adults

To date, cognitive intervention research has provided mixed but nevertheless promising evidence with respect to the effects of cognitive training on untrained tasks (transfer). However, the mechanisms behind learning, training effects and their predictors are not fully understood. Moreover, individual differences, which may constitute an important factor impacting training outcome, are usually neglected. We suggest investigating individual training performance across training sessions in order to gain finer-grained knowledge of training gains, on the one hand, and assessing the potential impact of predictors such as age and fluid intelligence on learning rate, on the other hand. To this aim, we propose to model individual learning curves to examine the intra-individual change in training as well as inter-individual differences in intra-individual change. We recommend introducing a latent growth curve model (LGCM) analysis, a method frequently applied to learning data but rarely used in cognitive training research. Such advanced analyses of the training phase allow identifying factors to be respected when designing effective tailor-made training interventions. To illustrate the proposed approach, a LGCM analysis using data of a 10-day working memory training study in younger and older adults is reported.     

A Call for an Unbiased Search for Moderators in Disfluency Research: Reply to Oppenheimer and Alter (2014)

In a commentary to our article, Oppenheimer and Alter stressed the importance of searching for moderators in disfluency research. We agree, but we would like to clarify two issues. First, unlike Oppenheimer and Alter, we assume that learner characteristics might indeed moderate the effects of disfluency. Second, conclusions concerning the impact of disfluency in educational settings might be biased because of the file‐drawer problem. To counteract this possibility, we want to encourage other researchers to publish their studies––regardless of whether they found (positive) effects of disfluency or not. Until then, any recommendation concerning the use of disfluency as an educational intervention seems premature.     

Individual Differences in Antisocial Punishment in Public Goods Situations: The Interplay of Cortisol with Testosterone and Dominance

This research investigates which endocrinological and psychological factors are associated with individuals' tendency to engage in destructive antisocial punishment, that is, to costly punish cooperative individuals in public goods situations. In this work, we focus on the interplay of endogenous cortisol with testosterone and dominance. We applied the dual‐hormone hypothesis according to which testosterone is positively associated with destructive and dominant behavior but only in individuals with low levels of cortisol. Study 1 shows that individuals are more likely to engage in destructive antisocial punishment in a public goods game with the option to punish when their testosterone level is high, given that their level of cortisol is low, which bolsters the dual‐hormone hypothesis. In contrast, no significant interaction effect of testosterone and cortisol emerges for the punishment of uncooperative free‐riders (altruistic punishment). In a second study, we build on these findings and document that self‐reported dominance is only positively associated with antisocial punishment (but not with altruistic punishment) when cortisol is low. In sum, the results indicate the importance of taking endocrinological and psychological factors (and their interactions) into account in order to reach a comprehensive understanding of individuals' behavior in social dilemma situations. Copyright © 2013 John Wiley & Sons, Ltd.     

Performance monitoring in obsessive–compulsive disorder: A temporo-spatial principal component analysis

Hyperactive performance monitoring is a robust finding in obsessive–compulsive disorder (OCD). Patients show increased amplitudes of the error-related negativity (ERN) and correct-related negativity (CRN). Recently, two temporo-spatial factors were shown to contribute to both ERPs in healthy individuals. In the present study, it was investigated whether the factor structure underlying ERN and CRN is similar in OCD and which factors differ between groups. A principal component analysis (PCA) was employed to investigate the temporo-spatial factor structure of ERN and CRN. Twenty-six OCD patients and 26 healthy controls conducted a flanker task. EEG data were analyzed as conventional ERP components and as factor scores derived from temporo-spatial PCA. ERP results showed expected increases in ERN and CRN amplitudes in OCD patients. For both groups, the PCA confirmed the assumed factor structure of a central and a fronto-parietal factor contributing to ERN and CRN. Factor scores of both factors were differently affected by response correctness in OCD. Alterations in factor scores indicate increased activity in both an outcome-independent monitoring process and an error-sensitive process, contributing to overactive performance monitoring in OCD.     

Simulating bistable perception with interrupted ambiguous stimulus using self-oscillator dynamics with percept choice bifurcation

A behavioral stochastic self-oscillator model is used for simulating interrupted ambiguous stimulus-induced percept reversals. The results provide further support for a dynamical systems foundation of cognitive and psychological problems as discussed in detail within the context of Gestalt psychology by Wagemans et al. (Concept Theor Found Psychol Bull 138(6):1218–1252, 2012), and for coordination dynamics of the brain (Kelso in Philos Trans R Soc B 367:906–918, 2012). Statistical evaluation of simulated reversal time series predicts a maximum of the percept reversal rate that conforms with a number of results in the literature. The macroscopic model is based on two inhibitorily coupled sets of three coupled nonlinear equations, one triplet for each percept. The derivation of our specific dynamics equations is based on a drastically simplified field theoretical approach using well-known phase synchronization for explaining brain dynamics on the macroscopic EEG level. The degree of coherence (contrast μ, 0 ≤ μ ≤ 1) of the superimposed fields required for onset of bistable dynamics is related to a phase synchronization index of EEG fields, and it is used in the present context as ambiguity control parameter. For quantitative agreement with the experimental data, the addition of a stochastic Langevin force term in the attention equation proved essential. Formal analysis leads to a quantification of well-known “cognitive inertia” and supports the interplay between percept choice (bifurcation) dynamics during stimulus onset and adaptive gain (attention fatigue) driven quasiperiodic percept reversals.     

Standards nichtstrafrechtlicher psychiatrischer Begutachtung

The introduction of the certificate for forensic psychiatry of the German Association of Psychiatry, Psychotherapy, Psychosomatics (DGPPN) in 2000 was a significant contribution to raising awareness of the formal and substantive requirements for forensic psychiatric evaluations and to develop a systematic quality improvement in forensic psychiatric expert services. By the special dominance of the certification in the field of penal law assessment, this proved to be problematic for many predominantly non-penal experts. This led to a requirement to develop a qualification for the non-penal expert opinions. In particular the increasing specialization of the psychiatric disciplines and the diversity of the legal issues and framework require a continuing education in the field of non-penal psychiatric assessments. Substantive and formal requirements are discussed and a continuous process of quality improvement and assurance is outlined. Last but not least a plea is made for close interdisciplinary exchange with the jurisprudence and the courts in the context of quality circles.     

Setting semantics: conceptual set can determine the physical properties that capture attention

The ability of a stimulus to capture visuospatial attention depends on the interplay between its bottom-up saliency and its relationship to an observer’s top-down control set, such that stimuli capture attention if they match the predefined properties that distinguish a searched-for target from distractors (Folk, Remington, & Johnston, Journal of Experimental Psychology: Human Perception & Performance, 18, 1030–1044 1992). Despite decades of research on this phenomenon, however, the vast majority has focused exclusively on matches based on low-level physical properties. Yet if contingent capture is indeed a “top-down” influence on attention, then semantic content should be accessible and able to determine which physical features capture attention. Here we tested this prediction by examining whether a semantically defined target could create a control set for particular features. To do this, we had participants search to identify a target that was differentiated from distractors by its meaning (e.g., the word “red” among color words all written in black). Before the target array, a cue was presented, and it was varied whether the cue appeared in the physical color implied by the target word. Across three experiments, we found that cues that embodied the meaning of the word produced greater cuing than cues that did not. This suggests that top-down control sets activate content that is semantically associated with the target-defining property, and this content in turn has the ability to exogenously orient attention.     

Sensory memory of illusory depth in structure-from-motion

When multistable displays (stimuli consistent with two or more equally plausible perceptual interpretations) are presented intermittently, their perceptions are stabilized by sensory memory. Independent memory traces are generated not only for different types of multistable displays (Maier, Wilke, Logothetis, & Leopold, Current Biology 13:1076–1085, 2003), but also for different ambiguous features of binocular rivalry (Pearson & Clifford, Journal of Vision 4:196–202, 2004). In the present study, we examined whether a similar independence of sensory memories is observed in structure-from-motion (SFM), a multistable display with two ambiguous properties. In SFM, a 2-D planar motion creates a vivid impression of a rotating 3-D volume. Both the illusory rotation and illusory depth (i.e., how close parts of an object appear to the observer) of an SFM object are ambiguous. We dissociated the sensory memories of these two ambiguous properties by using an intermittent presentation in combination with a forced-ambiguous-switch paradigm (Pastukhov, Vonau, & Braun, PLoS ONE 7:e37734, 2012). We demonstrated that the illusory depth of SFM generates a sensory memory trace that is independent from that of illusory rotation. Despite this independence, the specificities levels of the sensory memories were identical for illusory depth and illusory rotation. The history effect was weakened by a change in the volumetric property of a shape (whether it was a hollow band or a filled drum volume), but not by changes in color or size. We discuss how these new results constrain models of sensory memory and SFM processing.