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Alan D Pickering

Publications and source records attributed to Alan D Pickering.

6 recordsLinked to original sources
PubMed2006

The new reinforcement sensitivity theory: implications for personality measurement.

In this article, we review recent modifications to Jeffrey Gray's (1973, 1991) reinforcement sensitivity theory (RST), and attempt to draw implications for psychometric measurement of personality traits. First, we consider Gray and McNaughton's (2000) functional revisions to the biobehavioral systems of RST. Second, we evaluate recent clarifications relating to interdependent effects that these systems may have on behavior, in addition to or in place of separable effects (e.g., Corr, 2001; Pickering, 1997). Finally, we consider ambiguities regarding the exact trait dimension to which Gray's "reward system" corresponds. From this review, we suggest that future work is needed to distinguish psychometric measures of (a) fear from anxiety and (b) reward-reactivity from trait impulsivity. We also suggest, on the basis of interdependent system views of RST and associated exploration using formal models, that traits that are based upon RST are likely to have substantial intercorrelations. Finally, we advise that more substantive work is required to define relevant constructs and behaviors in RST before we can be confident in our psychometric measures of them.

Humans↗
PubMed2004

Disrupting feedback processing interferes with rule-based but not information-integration category learning.

The effect of a sequentially presented memory scanning task on rule-based and information-integration category learning was investigated. On each trial in the short feedback-processing time condition, memory scanning immediately followed categorization. On each trial in the long feedback-processing time condition, categorization was followed by a 2.5-sec delay and then memory scanning. In the control condition, no memory scanning was required. Rule-based category learning was significantly worse in the short feedback-processing time condition than in the long feedback-processing time condition or control condition, whereas information-integration category learning was equivalent across conditions. In the rule-based condition, a smaller proportion of observers learned the task in the short feedback-processing time condition, and those who learned took longer to reach the performance criterion than did those in the long feedback-processing time or control condition. No differences were observed in the information integration task. These results provide support for a multiple-systems approach to category learning and argue against the validity of single-system approaches.

Feedback↗
PubMed2002

The partial reinforcement extinction effect in humans: effects of schizophrenia, schizotypy and low doses of amphetamine.

The partial reinforcement extinction effect (PREE) was studied in human subjects. It has been suggested that the PREE depends on neural mechanisms critical to the cognitive dysfunction which underlines acute schizophrenia. We therefore predicted that the PREE should be reduced, through decreased resistance to extinction in the partial reinforcement (PR) condition, in various types of individual: (a) healthy volunteers given low doses of oral amphetamine; (b) those in the acute (but not chronic) phase of a schizophrenic illness and; (c) healthy volunteers with high scores on personality measures of schizotypy. Despite obtaining robust demonstrations of PREE in all experiments, none of these predictions were confirmed. A single, low dose, of amphetamine had no effect on either continuous reinforcement (CR) or partial reinforcement (PR). Acute and chronic schizophrenic patients showed a reduced PREE compared to controls. However this was due to increased resistance to extinction in the CR groups. Finally, high schizotypy scores were associated with greater PREE, attributable to both decreased extinction in the CR condition and increased extinction in the PR condition. The results of these experiments on human PREE provide no support that PREE is a valid paradigm with which to explore the cognitive dysfunction underlying schizophrenia.

Acute Disease↗
PubMed2002

Perceptual organization deficits in psychotic patients.

It has been proposed that a characteristic of schizophrenic processing is an abnormality of top-down processing. The relationship between impaired top-down processing and symptoms of reality distortion was investigated using a 'degraded interference' task. In this task, fragmented stimuli (Stroop words, control words and crosses) are presented on a computer screen, and the extent to which they are visually integrated is inferred by their interfering properties. It was predicted that psychotic individuals would fail to show an interference effect with degraded Stroop stimuli. This predicts the absence of a delay in reaction time in the experimental condition, which therefore cannot be attributed to a generalized deficit. A sample of inpatients experiencing positive symptoms was compared to a healthy control group. The results provided support for a deficiency in top-down processing, with the psychotic group failing to show the significant degraded interference effect found in the healthy controls. Degraded interference was associated with low verbal IQ, but with no other symptomatic or demographic variables.

Adult↗
PubMed2000

The relationship between cognitive inhibition and psychotic symptoms.

Cognitive models of schizophrenia have highlighted deficits of inhibitory attentional processes as central to the disorder. This has been investigated using "negative priming" (S. P. Tipper, 1985), with schizophrenia patients showing a reduction of negative priming in a number of studies. This study attempted to replicate these findings, but studied psychotic symptoms rather than the broad diagnostic category of schizophrenia. Psychotic individuals exhibiting positive symptoms were compared with asymptomatic psychiatric patients and with a normal control group. As predicted, the symptomatic group failed to show the usual negative priming effect, which was present in the asymptomatic and normal groups. A modest but significant correlation was found between negative priming and delusions. Neither diagnosis, nor affective or negative symptoms, nor chronicity, nor medication, was related to negative priming. These data replicate previous findings that positive symptoms are related to a reduction in cognitive inhibition, although considerable variability was observed among the psychotic patients.

Adult↗