Deficits in acquisition and extinction of conditioned responses in mGluR7 knockout mice

Metabotropic glutamate receptor 7 (mGluR7) is expressed in brain regions implicated in emotional learning and working memory, and previous behavioral experiments indicated contributions of mGluR7 to various complex behaviors. In the present study, we investigated the specific effects of mGluR7 deletion on a variety of conditioning paradigms that model crucial neurocognitive and psychopathological behavioral phenomena. Null-mutant mGluR7^−/− mice displayed defects during scheduled appetitive conditioning, acquisition and extinction of appetitive odor conditioning, extinction of response suppression-based conditioned emotional responding (CER), acquisition of discriminative CER, and contextual fear conditioning. mGluR7^−/− animals were slower to acquire the association between a conditioned stimulus and a positive or negative reinforcer, but eventually reached similar performance levels to their wildtype littermates. Notably, extinction learning of conditioned responses was slower in mGluR7^−/− compared to wildtype animals. The observed delays in the acquisition of complicated stimulus associations across conditioning procedures may suggest a critical role for mGluR7 in neurocognitive functions and psychopathology.     

Non-ruminative processing reduces overgeneral autobiographical memory retrieval in students

It has been suggested that overgeneral memory (OGM) represents a vulnerability marker for depression [Williams, J. M. G., Barnhofer, T., Crane, C., Hermans, D., Raes, F., Watkins, E., et al. (2007). Autobiographical memory specificity and emotional disorder. Psychological Bulletin, 133, 122-148]. One important underlying mechanism involved is rumination [e.g., Watkins, E., & Teasdale, J. D. (2001). Rumination and overgeneral memory in depression: Effects of self-focus and analytic thinking. Journal of Abnormal Psychology, 110, 353-357; Watkins, E., & Teasdale, J. D. (2004). Adaptive and maladaptive self-focus in depression. Journal of Affective Disorders, 82, 1-8]. It is as yet unclear to what extent the relationship between rumination and OGM also applies to nonclinical groups. The present study investigated this relationship in a nonclinical student sample, using an innovative sentence completion procedure to assess OGM. As hypothesized, the experimental induction of a concrete, process-focused (or non-ruminative) thinking style (n=102) led to less OGMs as compared to the experimental induction of an abstract, evaluative (or ruminative) thinking style (n=93). The present results add to the accumulating body of evidence that abstract, evaluative (or ruminative) thinking is a crucial underlying process of OGM, and expand prior literature by extending this idea to nonclinical individuals and by using a new procedure to assess OGM.     

Cognitive confidence in obsessive-compulsive disorder: distrusting perception, attention and memory

Previous studies have established that obsessive-compulsive disorder (OCD) is characterised by significant levels of distrust in memory (e.g. for actions). Ironically, this lowered confidence is at least in part due to repeated checking, which is assumed to lower perceptual processing and thereby reduces vividness and detail of the recollections. In a previous study, Hermans, D., Martens, K., De Cort, K., Pieters, G., and Eelen, P. [(2003). Reality monitoring and metacognitive beliefs related to cognitive confidence in OCD. Behaviour Research and Therapy, 41, 383-401] observed that OCD is not only characterised by reduced confidence in memory, but also by a similar distrust in attention (Hermans et al., 2003). The present study aimed at replicating and extending this finding. It was observed (a) that patients suffering from OCD showed less confidence in attention and memory than a clinical and a nonclinical control group; (b) that confidence in attention was uniquely related to checking behaviour, and (c) that repeated checking caused increased levels of distrust in attention. In addition, it was observed that cognitive distrust while performing OCD-related actions not only extends to attention, but also to perception. It is argued that research on metacognition in OCD should move beyond the study of memory.     

Time course of the Simon effect in pointing movements for horizontal, vertical, and acoustic stimuli: evidence for a common mechanism

In the Simon effect, responses to a non-spatial attribute are faster when the irrelevant spatial position of the stimulus corresponds to the position of the response. It was suggested that there are two distinct mechanisms involved in the Simon effect. In the visuomotor Simon effect, the stimulus transiently activates the corresponding response which results in a decaying Simon effect function (i.e., the Simon effect decreases in slower reaction time [RT]-bins). In contrast, the cognitive Simon effect arises from a conflict between stimulus and response codes and is associated with a stable Simon effect function (i.e., the Simon effect is the same in fast and slow RT-bins). We recorded RTs and motor parameters of pointing movements in a Simon paradigm. Consistent with the previous research, the time course of the Simon effect in RTs was stable with vertical visual and horizontal acoustic stimuli (cognitive Simon tasks), but decreased with horizontal visual stimuli (visuomotor Simon task). In contrast, the Simon effect in motor parameters decreased across RT-bins in all conditions, supporting the idea that only a single, common mechanism underlies the Simon effect.     

The extrinsic affective Simon task as an instrument for indirect assessment of prejudice

We report one study that explored the applicability of the Extrinsic Affective Simon Task (EAST) as an indirect measure of prejudice. The EAST detected known differences in reactions revealing that a Turkish outgroup was spontaneously evaluated more negatively than the German ingroup. More importantly, EAST effects were meaningfully correlated with measures of explicit prejudice expression. This relation, however, was moderated by participants' motivation to control prejudice expression. In addition, we tested considerations regarding the role of a task‐switch account for the explanation of EAST scores and found that only EAST scores of task‐switch trials were related to explicit prejudice expression. This supports a task‐switch explanation of the EAST. Results indicate that the EAST is suitable for the assessment of interindividual differences in intergroup prejudice. Implications for the indirect assessment of automatic prejudice activation are discussed. Copyright © 2008 John Wiley & Sons, Ltd.     

Design and power analysis: n and confidence intervals of means

In this study, we analyzed the validity of the conventional 80% power. The minimal sample size and power needed to guarantee non-overlapping (1-alpha)% confidence intervals for population means were calculated. Several simulations indicate that the minimal power for two means (m = 2) to have non-overlapping CIs is .80, for (1-alpha) set to 95%. The minimal power becomes .86 for 99% CIs and .75 for 90% CIs. When multiple means are considered, the required minimal power increases considerably. This increase is even higher when the population means do not increase monotonically. Therefore, the often adopted criterion of a minimal power equal to .80 is not always adequate. Hence, to guarantee that the limits of the CIs do not overlap, most situations require a direct calculation of the minimum number of observations that should enter in a study.     

Counter-regulation in affective attentional biases: a basic mechanism that warrants flexibility in emotion and motivation

We investigated whether anticipating positive or negative future outcomes during goal pursuit has a modulatory effect on attentional biases for affectively congruent and incongruent distractor stimuli. In two experiments using a flanker task, we found that distractor interference of stimuli signaling opportunities or dangers was stronger after inducing an outcome focus of the opposite valence. The second experiment provided additional evidence that the incongruency effect reflects a global shift in affective attentional biases and is not mediated by changes in strategies or in the perceived valence of the stimuli. It is argued that counter-regulation in affective attentional biases serves an important function for the regulation of emotion and action.     

Associations between emotions: correspondence across different types of data and componential basis

Two issues regarding associations between negative emotions are addressed: (i) whether different types of data imply similar associations and (ii) whether these associations can be accounted for by the overlap between emotion components. In study 1, issue (i) was examined using individual differences covariation, situational covariation, and judged emotion similarity data. Results showed that the associations implied by the different data types were highly similar. Regarding issue (ii), we argue theoretically that component overlap may account for the obtained correspondence. Study 2 empirically demonstrated that the different types of association were strongly related to overlap in appraisals and action tendencies. Similarity judgments, however, seemed to be primarily based on emotion co‐occurrence, and were only to a smaller degree directly related to component overlap. Copyright © 2004 John Wiley & Sons, Ltd.     

Manipulating self‐esteem with subliminally presented words

A method for the unobtrusive manipulation of self‐esteem is presented. In four experiments, participants were subliminally exposed to either negative or positive adjectives paired with a self‐referring word (‘I’). The manipulation affected both self‐esteem and a probable consequence of self‐esteem (self‐serving bias) but did not affect mood or evaluation of a non‐self‐related object. When the adjectives were paired with a non‐self‐referring word, the manipulation had no effects. Together, the findings suggest that a) the method is an effective means of manipulating self‐esteem without side‐effects on mood and b) selective activation of evaluative self‐knowledge is the mediating process. Thus, the method promises to be a useful tool for the experimental investigation of the consequences of self‐esteem. Copyright © 2003 John Wiley & Sons, Ltd.     

Anticipated Success at Unconscious Goal Pursuit: Consequences for Mood, Self-Esteem, and the Evaluation of a Goal-Relevant Task

This study extends recent research showing that fulfillment of unconscious goals can have the same affective consequences as fulfillment of conscious goals (T. L. Chartrand, 2001). Participants were unobtrusively primed with stimuli either relevant or irrelevant to the goal to seek knowledge. Next, an opportunity to fulfill the knowledge-seeking goal was announced (i.e., a test and subsequent feedback on a fictitious cognitive ability). As expected, participants in the knowledge-goal condition responded more positively to the announcement in terms of mood, self-esteem, and test evaluation than did participants in the no-goal condition. Consistent with a motivational account, the priming procedure did not influence mood and self-esteem when these variables were measured before test announcement.