On the transmission of partial information: inferences from movement-related brain potentials.

Results are reported from a new paradigm that uses movement-related brain potentials to detect response preparation based on partial information. The paradigm uses a hybrid choice-reaction go/nogo procedure in which decisions about response hand and whether to respond are based on separate stimulus attributes. A lateral asymmetry in the movement-related brain potential was found on nogo trials without overt movement. The direction of this asymmetry depended primarily on the signaled response hand rather than on properties of the stimulus. When the asymmetry first appeared was influenced by the time required to select the signaled hand, and when it began to differ on go and nogo trials was influenced by the time to decide whether to respond. These findings indicate that both stimulus attributes were processed in parallel and that the asymmetry reflected preparation of the response hand that began before the go/nogo decision was completed.     

The dimensionality of the flanker compatibility effect: A psychophysiological analysis

The psychophysiological approach was used to evaluate the effects of feature similarity and intrinsic response mapping on the flanker compatibility effect. Symbol (e.g., < > < and < / <) and letter arrays (e.g., HCH and SCS) were used. Results showed that delays in stimulus evaluation and both peripheral and central response competition contributed to the compatibility effect, with the contribution of these processes depending on feature similarity and the intrinsic response mapping of the stimuli. For letter stimuli, the difference in the size of the compatibility effect for similar and dissimilar arrays could be accounted for in terms of stimulus evaluation. For symbol arrays, differences in size of the compatibility effect could be accounted for by response competition. Thus, symbol and letter arrays do not appear to be processed differently; what is different is the degree to which stimulus and response-related processes are affected by incompatibility.     

The relationship between personality,anger expression,and perceived family control among incarcerated male juveniles

The literature suggests that a multitude of psychological and social factors can interact to place adolescents at risk for aggression and violence. This study examined three of these factors: personality, affect, and family. Using a heterogeneous sample of male adolescents at risk for violence, a hierarchical, agglomerative cluster analysis was conducted to categorize these adolescents in terms of personality characteristics. Results of the analysis suggested three clusters of at-risk adolescents. Examination of the three cluster types found distinctions between groups on anger expression, trait anger, and trait anxiety, but not family control. It was concluded that, among male delinquents, elevated psychopathology is associated with higher anger and anxiety, but not higher family control.     

A computational account of altered error processing in older age: Dopamine and the error-related negativity

When participants commit errors or receive feedback signaling that they have made an error, a negative brain potential is elicited. According to Holroyd and Coles’s (in press) neurocomputational model of error processing, this error-related negativity (ERN) is elicited when the brain first detects that the consequences of an action are worse than expected. To study age-related changes in error processing, we obtained performance and ERN measures of younger and high-functioning older adults. Experiment 1 demonstrated reduced ERN amplitudes in older adults in the context of otherwise intact brain potentials. This result could not be attributed to uncertainty about the required response in older adults. Experiment 2 revealed impaired performance and reduced response- and feedback-related ERNs of older adults in a probabilistic learning task. These age changes could be simulated by manipulation of a single parameter of the neurocomputational model, this manipulation corresponding to weakened phasic activity of the mesencephalic dopamine system.     

Implicit memory bias for threat-relevant information in individuals with generalized social phobia

The authors used a noise judgment task to investigate implicit memory bias for threat in individuals with generalized social phobia (GSP). Participants first heard neutral sentences (e.g., "The manual tells you how to set up the tent.") and social-threat sentences (e.g., "The classmate asks you to go for drinks."). Implicit memory for these sentences was then tested by asking participants to rate the volume of noise accompanying the presentation of these "old" sentences intermixed with "new" sentences that had not been previously presented. Implicit memory for old sentences is revealed when participants rate the noise accompanying old sentences as less loud than the noise accompanying new sentences. Those with GSP demonstrated an implicit memory bias for social-threat sentences, whereas controls did not. This differential priming effect suggests that information about threat may be automatically accessed in GSP.     

Effects of varying levels of anxiety within social situations: relationship to memory perspective and attributions in social phobia

Cognitive-behavioral theorists (Clark & Wells, 1995: Clark, D. M. & Wells, A. (1995). A cognitive model of social phobia. In R. G. Heimberg, M. R. Liebowitz, D. A. Hope, & F. R. Schneier (Eds.), Social phobia: Diagnosis, assessment, and treatment (pp. 69-93). New York: Guilford Press; Rapee & Heimberg, 1997: Rapee, R. M., & Heimberg, R. G. (1997). A cognitive-behavioral model of anxiety in social phobia. Behaviour Research and Therapy, 35, 741-756.) propose that individuals with social phobia form mental images of themselves as if from an external point of view. Research by Wells and colleagues has shown that, when recalling anxiety-provoking social situations, individuals with social phobia are more likely to take an observer perspective (seeing oneself as if from an external point of view) whereas control subjects are more likely to take a field perspective (as if looking out through one's own eyes). Furthermore, this pattern is specific to social events, as both groups recall non-social events from a field perspective (see Wells, Clark & Ahmad, 1998: Wells, A., Clark, D. M., & Ahmad, S. (1998). How do I look with my minds eye: perspective taking in social phobic imagery. Behaviour Research and Therapy, 36, 631-634; Wells & Papageorigou, 1999: Wells, A. & Papageorgiou, C. (1999). The observer perspective: Biased imagery in social phobia, agoraphobia, and blood/injury phobia. Behaviour Research and Therapy, 37, 653-658). In the current study, individuals with social phobia took more of an observer perspective than non-anxious controls when recalling high anxiety social situations. However, both groups took a predominantly field perspective for memories of medium or low anxiety social situations. As memory perspective has also been shown to be related to causal attributions, we examined this relationship in our sample. Memories of low, medium, and high anxiety social situations were differentially related to attributions for each group. Patients' attributions for their performance became more internal, stable, and global as the anxiety level of the situation increased, while the attributions of control subjects showed the opposite pattern.     

Distinguishing obsessive features and worries: the role of thought-action fusion

Obsessions are a key feature of obsessive-compulsive disorder (OCD), and chronic worry is the cardinal feature of generalized anxiety disorder (GAD). However, these two cognitive processes are conceptually very similar, and there is a need to determine how they differ. Recent studies have attempted to identify cognitive processes that may be differentially related to obsessive features and worry. In the current study we proposed that (1) obsessive features and worry could be differentiated and that (2) a measure of the cognitive process thought-action fusion would distinguish between obsessive features and worry, being strongly related to obsessive features after controlling for the effects of worry. These hypotheses were supported in a sample of 173 undergraduate students. Thought-action fusion may be a valuable construct in differentiating between obsessive features and worry.     

The effect of practice on recall of emotional information in individuals with generalized social phobia

Understanding memory processes in social anxiety is important because these individuals often report negative memories of anxiety-provoking situations and because of the recent emphasis on learning and memory in models of anxiety. The authors examined the effect of learning on memory for negative social, positive social, and nonsocial information using the retrieval-induced forgetting paradigm in individuals with generalized social phobia (GSPs) and in nonanxious controls (NACs). Words were presented in 1 of 3 practice conditions: practiced words from a practiced category, unpracticed words from a practiced category, and unpracticed words from an unpracticed category. GSPs and NACs showed the same patterns of memory for practice categories for positive social and nonsocial words. However, for negative social words, GSPs benefited less from practice and were hurt less from the effect of practicing competing negative social information than were NACs. This pattern of processing may hamper GSPs' learning of, and habituation to, negative social information.