Integrated versus segregated accounting and the magnitude effect in temporal discounting

Temporal discounting rates in humans generally decrease as the amount of reward increases, a phenomenon known as themagnitude effect. In the present study, we examined whether temporal discounting and the magnitude effect are related to segregation of choices in terms of gains or losses for waiting for or expediting receipt of a reward. Subjects (N = 24) responded to a series of hypothetical choices about amounts of money available either immediately or after a delay. The immediate and delayed amounts either were presented as integrated amounts in the baseline condition or were segregated as differential gains or losses for choosing delayed or expedited consumption (delay and speedup conditions, respectively). Temporal discounting rates decreased in the segregated conditions, in accord with the standard discounted utility model but contrary to the hypothesis that the subjects were choosing on the basis of reward differentials in the baseline condition. The size of the magnitude effect was comparable in the baseline and the delay conditions but decreased in the speed-up condition. These results challenge explanations of the magnitude effect in terms of an increasing proportional sensitivity property of the utility function (Loewenstein & Prelec, 1992) and the hypothesis that subjects choose on the basis of differentials even when the rewards are presented as integrated amounts.     

The effect of midazolam on implicit and explicit memory in category exemplar production and category cued recall

Transfer-appropriate processing theory (Roediger, Weldon, & Challis, 1989) proposes that dissociations between performance on explicit and implicit memory tests arise because these tests often rely on different types of information processing (e.g., perceptual processing vs conceptual processing). This perspective predicts that implicit and explicit memory tasks that rely primarily on conceptual processing should show comparable results, not dissociations. Numerous studies have demonstrated such similarities. It is, however, possible that these results arise from explicit memory contamination of performance on implicit memory tasks. To address this issue, an experiment was conducted in which participants were administered the sedative midazolam prior to study. Midazolam is known to create a temporary, but dense, period of anterograde amnesia. The effects of blocking stimulus materials by semantic category at study and generation at study were investigated on category exemplar production and category-cued recall. The results of this study demonstrated a dissociation of the effects of midazolam on category exemplar production and category-cued recall. Specifically, midazolam reduced the effect of blocking stimulus materials in category-cued recall, but not in category exemplar production. The differential effect of midazolam on explicit and implicit memory is at odds with transfer-appropriate processing theory and suggests that theories of memory must distinguish the roles of different types of conceptual processing on implicit and explicit memory tests.     

The use of imagery in cognitive therapy for psychosis: a case example

There has been a long tradition of studying imagery in relation to psychotic symptoms. Recent studies have suggested that imagery may be involved in the development and maintenance of psychotic symptoms (hallucinations and delusions in particular). Following a review of this literature, including work conducted by the author and colleagues, a case study is used to illustrate the clinical applications of this work. Working with images that were associated with persecutory delusions appeared to contribute to a reduction in distress, preoccupation, and conviction in relation to these beliefs, which were assessed using a standardised measure (PSYRATS). The implications for theory, practice, and future research are considered.     

And when shall a little child lead them? evidence for an altercasting theory of source credibility

In two crucial test experiments pitting altercasting against traditional source credibility theories (Hovland, Janis, & Kelley, 1953; Kelman, 1958), students received a message emphasizing either technical or protective themes attributed to a child or an expert. Traditional theories predict an expert should be more effective than a child. According to altercasting theory, credibility is a function of the privileges and responsibilities associated with positions in a role-set. A child places a message recipient into the role of protector and is most effective when arguing for protective as opposed to technical messages. An expert is most effective when arguing within a domain of expertise (technical issues) as opposed to common opinion. The results overwhelmingly support an altercasting interpretation of source credibility.     

Linguistic focus and good-enough representations: An application of the change-detection paradigm

A number of lines of study suggest that word meanings are not always fully exploited in comprehension. In two experiments, we used a text-change paradigm to study depth of semantic processing during reading. Participants were instructed to detect words that changed across two consecutive presentations of short texts. The results suggest that the full details of word meanings are not always incorporated into the interpretation and that the degree of semantic detail in the representation is a function of linguistic focus. The results provide evidence for the idea that representations are only good enough for the purpose at hand (Ferreira, Bailey, & Ferraro, 2002).     

Adolescent personality: a five-factor model construct validation

The purpose of this study was to investigate convergent and discriminant validity of the five-factor model of adolescent personality in a school setting using three different raters (methods): self-ratings, peer ratings, and teacher ratings. The authors investigated validity through a multitrait-multimethod matrix and a confirmatory factor analysis correlated trait, uncorrelated method model. With the exception of Emotional Stability, each analysis demonstrated similar patterns and together provided support for the convergent and discriminant validity of the five-factor model structure of adolescent personality. However, among the three raters, self-ratings of personality provided a comparatively weaker method for assessing adolescent personality. The influences of agreement between self and other raters are discussed in relation to contrast, perceiver, and target effects; expert observer effects; the degree of acquaintanceship; and the effect of the social context.     

Data quality affects meta-analytic conclusions: a response to Miner and Raju (2004) concerning entrepreneurial risk propensity

J. B. Miner and N. S. Raju (2004) contended that there are additional studies that compare the risk propensity of entrepreneurs and managers, which, when added to the data from W. H. Stewart and P. L. Roth (2001) and meta-analyzed, produce relationships between risk propensity and entrepreneurial status that are substantially weaker than previously believed. This conclusion was evaluated by identifying and examining methodological problems associated with their inclusion of effect sizes (i.e., ds) from studies with variables not relevant to research questions, dependent samples, extraneous variance in outcome variables, and confusion of constructs. When these methodological issues were addressed, a new meta-analysis indicated an overall conclusion consistent with that of Stewart and Roth, but the results varied according to instrumentation, particularly objective instrumentation (observed d = 0.31) versus the Miner Sentence Completion Scale-Form T (observed d = -0.35).