Identification of everyday objects on the basis of fragmented outline versions

Although Attneave (1954 Psychological Review 61 183 193) and Biederman (1987 Psychological Review 94 115-147) have argued that curved contour segments are most important in shape perception, Kennedy and Domander (1985 Perception 14 367-370) showed that fragmented object contours are better identifiable when straight segments are shown. We used the set of line drawings published by Snodgrass and Vanderwart (1980 Journal of Experimental Psychology: Human Learning and Memory 6 174-215), to make outline versions that could be used to investigate this issue with a larger and more heterogeneous stimulus set. Fragments were placed either around the 'salient' points or around the midpoints (points midway between two salient points), creating curved versus relatively straight fragments when the original outline was fragmented (experiment 1), or angular and straight fragments when straight-line versions were fragmented (experiment 2). We manipulated fragment length in each experiment except the last one, in which we presented only selected points (experiment 3). While fragmented versions were on average more identifiable when straight fragments were shown, certain objects were more identifiable when the curved segments or the angles were shown. A tentative explanation of these results is presented in terms of an advantage for straight segments during grouping processes for outlines with high part salience, and an advantage for curved segments during matching processes for outlines with low part salience.     

Effector-related sequence learning in a bimanual-bisequential serial reaction time task

In a bimanual-bisequential version of the serial reaction time (SRT) task participants performed two uncorrelated key-press sequences simultaneously, one with fingers of the left hand and the other with fingers of the right hand. Participants responded to location-based imperative stimuli. When two such stimuli appeared in each trial, the results suggest independent learning of the two sequences and the occurrence of intermanual transfer. Following extended practice in Experiment 2, transfer of acquired sequence knowledge was not complete. Also in Experiment 2, when only one stimulus appeared in each trial specifying the responses for both hands so that there was no basis for separate stimulus-stimulus or separate response-effect learning, independent sequence learning was again evident, but there was no intermanual transfer at all. These findings suggest the existence of two mechanisms of sequence learning, one hand-related stimulus-based and the other motor-based, with only the former allowing for intermanual transfer.     

Psychotherapie und die Anerkennung des Fremden Kommentar zu D. Orlinsky

Die Arbeit setzt sich drei Ziele: Sie will Grenzen und Einschränkungen aufzeigen, die im aktuell gebräuchlichen Störungsbegriff enthalten sind. Sie will zeigen, was verloren geht, wenn die Person des einzelnen Kranken, verstanden als Individualität, Subjektivität und Identität, in Diagnostik und Therapie zu wenig beachtet wird, und sie will darauf hinweisen, dass soziale, kulturelle und gesellschaftliche Faktoren in der Psychiatrie und Psychotherapie zu berücksichtigen sind. Methodisch bedient sich die Arbeit v. a. wissenschaftstheoretischer und philosophischer Argumente. Sie kommt zur Schlussfolgerung, dass die Grenzen von Diagnostik und Therapie in allen drei Bereichen eine gemeinsame Grundlage haben. Sie lassen sich überwinden, wenn Psychiatrie und Psychotherapie selbstreflexiv die Grenzen der eigenen Verfahren berücksichtigen und wenn Fremdheit und Andersheit (des Symptoms, des Mitmenschen, des kulturellen und gesellschaftlichen Umfelds) prinzipiell anerkannt werden. Der Text versteht sich als Kommentar zu D. Orlinskys Ausführungen zur störungsspezifischen Psychotherapie aus der Sicht des Psychotherapieforschers in diesem Heft.     

Gender Differences in the Choice of Computer Courses: Applying an Expectancy-Value Model

The choice of computer courses has a direct influence on the development of computer literacy. It is alarming, therefore, that girls seem to choose computer courses less frequently than boys. The present paper examines (a) whether these often-reported gender differences also occur at the early high school level (Study 1) and (b) how these differences can be predicted by applying an expectancy-value model to the domain of computing (Study 2). Both studies clearly show gender differences in the choice of computer courses in children between 10 and 16 years in the real-life situation of choosing courses at school. In Study 2, the suggested expectancy-value model is tested using data from 159 students and 137 parents. The model shows a good fit to the data, and the observed gender differences in the choice of computer course could be predicted by differences in the value placed on computers and the expectations of success. However, these differences could only be partly explained by differences in perceived parental attitudes, and there were only weak relationships between parental attitudes and the corresponding perceptions of the students. Educational implications of the findings and suggestions for future research are discussed.     

A diffusion model decomposition of the practice effect

When people repeatedly perform the same cognitive task, their mean response times (RTs) invariably decrease. The mathematical function that best describes this decrease has been the subject of intense debate. Here, we seek a deeper understanding of the practice effect by simultaneously taking into account the changes in accuracy and in RT distributions with practice, both for correct and error responses. To this end, we used the Ratcliff diffusion model, a successful model of two-choice RTs that decomposes the effect of practice into its constituent psychological processes. Analyses of data from a 10,000-trial lexical decision task demonstrate that practice not only affects the speed of information processing, but also response caution, response bias, and peripheral processing time. We conclude that the practice effect consists of multiple subcomponents, and that it may be hazardous to abstract the interactive combination of these subcomponents in terms of a single output measure such as mean RT for correct responses. Supplemental materials may be downloaded from http://pbr .psychonomic-journals.org/content/supplemental.     

A Hierarchical Ornstein–Uhlenbeck Model for Continuous Repeated Measurement Data

In this paper, we present a diffusion model for the analysis of continuous-time change in multivariate longitudinal data. The central idea is to model the data from a single person with an Ornstein–Uhlenbeck diffusion process. We extend it hierarchically by allowing the parameters of the diffusion process to vary randomly over different persons. With this approach, both intra and interindividual differences are analyzed simultaneously. Furthermore, the individual difference parameters can be regressed on covariates, thereby providing an explanation of between-person differences. Unstructured and unbalanced data pose no problem for the model to be applied. We demonstrate the method on data from an experience sampling study to investigate changes in the core affect. It can be concluded that different factors from the five factor model of personality are related to features of the trajectories in the core affect space, such as the cross-correlation and variability of the changes.     

The assessment of self-oriented and socially prescribed perfectionism: subscales make a difference

Campbell and Di Paula (2002) suggested differentiating Perfectionistic Striving and Importance of Being Perfect subscales when measuring self-oriented perfectionism and Others' High Standards and Conditional Acceptance subscales when measuring socially prescribed perfectionism. In this study, we investigated the utility of this differentiation by analyzing data from 1,041 students and examining correlations with positive striving and maladaptive evaluation concerns aspects of perfectionism and with positive and negative indicators of well-being and psychological adjustment. As expected, (a) Perfectionistic Striving scores showed higher correlations with positive striving aspects of perfectionism and with positive indicators of well-being and adjustment than Importance of Being Perfect scores, and (b) Conditional Acceptance scores showed higher correlations with maladaptive evaluation concerns aspects of perfectionism and with negative indicators of well-being and adjustment than Others' High Standards scores. The findings indicate that Campbell and Di Paula's differentiation provides for a more detailed and informative assessment of multidimensional perfectionism and its different aspects. Moreover, it provides for new insights into self-oriented and socially prescribed perfectionism and their relationships and associations.     

International Union of History and Philosophy of Science Division of Logic,Methodology and Philosophy of Science (IUHPS/DLMPS)

International Union of History and Philosophy of Science Division of Logic, Methodology and Philosophy of Science (IUHPS/DLMPS)Bulletin no. 16     

Children's voluntary exploration and preference for tactually presented nonsense shapes differing in complexity

This study represents an extension of research on children's response to nonsense shapes varying in complexity to the tactual modality. Wooden cut-out shapes varying in number of turns from 3 to 40 were presented to children at Grades I, III, and VI, both for voluntary haptic exploration, and for preference choices. Both of these measures yielded monotonically increasing functions in the oldest group, while the youngest showed a similar but much flatter gradient for exploration times, and an inverted-U shaped preference function; data for the Third Grade subjects were in both cases intermediate. Supplementary data based on an analysis of preference choice latencies for stimulus pairs of adjacent levels of complexity, as well as on ratings of subject's mode of exploration of the stimuli under both response sets showed a marked shift from a predominantly passive to an increasingly active mode of exploration. These results are related to the age differences for the exploration-time and preference data, and discussed in relation to Schachtel's differentiation between allocentric and autocentric modes of perception.