Acquired equivalence and distinctiveness of cues: II. Neural manipulations and their implications

Neural manipulations were used to examine the mechanisms that underlie the acquired equivalence and distinctiveness of cues in rats. Control rats and those with excitotoxic lesions of either the hippocampus (HPC) or entorhinal cortex (EC) acquired the following conditional discrimination: In Contexts A and B, Stimulus X-->food and Stimulus Y-->no food, and in Contexts C and D, Y-->food and X-->no food. Rats then received many food pellets in A but not in C. After this treatment, control rats showed more magazine activity in B than in D--an acquired equivalence-distinctiveness effect. This effect was also evident in HPC rats but not in EC rats. These results indicate that changes in stimulus distinctiveness are dissociable from the process of conditional learning.     

The accuracy of abstracts in psychology journals

This article provides an empirically supported reminder of the importance of accuracy in scientific communication. The authors identify common types of inaccuracies in research abstracts and offer suggestions to improve abstract-article agreement. Abstracts accompanying 13% of a random sample of 400 research articles published in 8 American Psychological Association journals during 1997 and 1998 contained data or claims inconsistent with or missing from the body of the article. Error rates ranged from 8% to 18%, although between-journal differences were not significant. Many errors (63%) were unlikely to cause substantive misinterpretations. Unfortunately, 37% of errors found could be seriously misleading with respect to the data or claims presented in the associated article. Although deficient abstracts may be less common in psychology journals than in major medical journals (R. M. Pitkin, M. A. Branagan, & L. F. Burmeister, 1999), there is still cause for concern and need for improvement.     

Action-based and vision-based selection of input: Two sources of control

In the first part of this paper we review evidence suggesting that there exists a mechanism that selects input on the basis of its similarity to the required action. This response-based input selection differs from the more established space- and object-based input selection in that it is not constrained by the structure of the input. Our evidence suggests that the two-choice Stroop effect is caused by this response-based selection mechanism. By contrast, it is known that the flanker effect is determined by the space- and object- based selection mechanisms. We explore whether the conflict resolution of the Stroop and flanker tasks is different as well by embedding these two tasks in a PRP (Psychological Refractory Period) paradigm. We show that the Stroop and the PRP effects are additive whereas the flanker and the PRP effects are underadditive, suggesting that the processes in charge of the conflict resolution in the Stroop and the flanker tasks are indeed different. We discuss possible reasons for this difference, and discuss possible ways in which the response-based mechanism can be implemented in information processing models.     

Win-shift and win-stay learning in the short-beaked echidna (<Emphasis Type="Italic">Tachyglossus aculeatus</Emphasis>)

Numerous previous investigators have explained species differences in spatial memory performance in terms of differences in foraging ecology. In three experiments we attempted to extend these findings by examining the extent to which the spatial memory performance of echidnas (or "spiny anteaters") can be understood in terms of the spatio-temporal distribution of their prey (ants and termites). This is a species and a foraging situation that have not been examined in this way before. Echidnas were better able to learn to avoid a previously rewarding location (to "win-shift") than to learn to return to a previously rewarding location (to "win-stay"), at short retention intervals, but were unable to learn either of these strategies at retention intervals of 90 min. The short retention interval results support the ecological hypothesis, but the long retention interval results do not. Electronic Publication     

Dimensional complexity and power spectral measures of the EEG during functional versus predicative problem solving

Electroencephalograms were recorded in 22 men while solving tasks of visual-pattern completion and during mental relaxation. They were primed (by foregoing trials) to solve these tasks either in a predicative or functional mode of thinking. Predicative thinking required that in order to complete the pattern the subject had to get involved with the logic of the static structure of the pattern and therefore had to recognize the recurrence of certain features of the elements (e.g., shape, color, and size). Functional thinking required involvement in a dynamic reading of the logic of the pattern and therefore to search for operations and actions to be performed on the pattern elements (e.g., pushing, mirroring, and rotating). The EEG complexity during predicative thinking decreased in comparison to functional thinking and mental relaxation, with this reduction being most pronounced over the right parietal cortex. A reduction in dimensional complexity during functional thinking as compared to mental relaxation, which was concentrated over the left central cortex, although significant, was less clear. The reduced EEG complexity during predicative thought, dominant over the right hemisphere, could reflect increased competitive inhibition among respective cortical neuron assemblies in association with the visual analysis of static element features, converging upon those predicates relevant for the solution.     

The Factor Structure of the Beavers Interactional Scales

Confirmatory factor analysis and regression analyses of the Beavers Interactional Scales did not appear to support the model offered by its developers, namely, several specified family attributes contributing respectively to two global factors of Family Competence and Family Style. Moreover, regression analysis indicated that only three of 12 items predicted raters' assessments of Global Family Health, and one of seven items predicted Global Family Style. Individuals interested in the family dynamic centripetal/centrifugal might best think of that as a unitary entity and rate it accordingly.     

The role of mental relaxation in experimental desensitization

Certain evidence indicates that training in peripheral muscle relaxation is not an essential factor in the successful experimental desensitization of phobias. Rachman (1968) has suggested that a sense of calmness or mental relaxation is the necessary component and that all the preliminary training techniques leading to successful desensitization, have, as the basis for their success, the inadvertent induction of this state of mental calmness. The direct induction of mental relaxation then, ought to be at least as effective an adjunct to desensitization as training in muscle relaxation. Using spider phobia as the target behaviour, the present study compared the effectiveness of (a) hierarchy presentation paired with deep muscle relaxation; (b) hierarchy presentation paired with instructions to feel calm and relaxed and alternated with imagining a pleasant scene; (c) a combination of these two procedures paired with hierarchy presentation; and (d) a placebo control procedure. The treatment groups all improved significantly more than controls and there there were no differences between treatments. The results were seen as offering strong support of Rachman's position. Both theoretical and practical implications of the results are discussed with consideration being given to the nature of “mental calmness”.     

Plantinga’s Reformed Epistemology: What’s the Question?

Alvin Plantingas Warranted Christian Belief is without questionone of the central texts of the Reformed epistemology movement. Critiques of Plantingas defence have been both multiple and varied. As varied as these responses are, however, it is my contention that many of them amount to the same thing. It is the purpose of this paper to offer an overview of the main lines of attack that have been directed as Plantingas project, and thereafter to show how many, if not most, of these objections can be understood as versions or aspects of the same criticism, what I call the Inadequacy Thesis.