Subject knowledge of the Experimenter''s interest in handedness and familial sinistrality variables and laterality test outcomes

We investigated the possible influence of common "demand characteristics" on the results on behavioral language laterality tasks. The demand characteristics were (1) whether Ss were or were not recruited for study according to their handedness, and (2) whether a detailed familial sinistrality inquiry was conducted before or after the tasks. Tasks were the Dichotic Consonant Vowel Task (DCVT) and the Bilateral Object Naming Latency Task (BONLT). Results showed no effect of demand characteristics on the BONLT. On the DCVT, however, prior inquiry regarding familial sinistrality was associated with significantly reduced right ear advantages (REAs). Interactions showed that the greatest reduction in REAs occurred in Ss with left-handedness in their families, who were asked about familial sinistrality prior to the tasks, who took the DCVT after the BONLT, and who were also recruited by handedness. Results, though generally reassuring regarding the robustness of the tasks against these sources of bias, raise some cautions for the DCVT.     

Interactions between area and numerosity

Summary The concept of filled area, i.e. the impressionistic ensemble of parts of a stimulus field occupied by dots, is used to account for various kinds of numerosity illusions due to perceptual interaction between a number of dots and their spatial arrangement. A measure of filled area is derived from a model for the perceptual clustering of dots on the basis of relative proximity. It is shown that the quantified concept of filled area successfully predicts illusion data from earlier studies. Subsequently, a two-alternatives forced-choice numerosity experiment is reported, the data of which gave further evidence of the predictive power of the filled-area hypothesis. Our approach is discussed with respect to spatial features of dot stimuli that might be in rivalry with the filled-area factor in numerosity-estimation tasks.     

Many stimuli are frightening,but some are more frightening than others: The contributions of preparedness,dangerousness, and unpredictability to making a stimulus fearful

The nonrandom distribution of situational fears has been explained by evolutionary survival relevance of specific fears. Thirty-eight stimuli were taken from the literature on preparedness and were scored on fearfulness, objective dangerousness, and spatiotemporal unpredictability by three separate groups of students. The same items were scored on survival relevance by 15 biologists. Fearfulness of cues significantly correlated not only with survival relevance but also, and even more strongly, with dangerousness and unpredictability. While the fear/survival relevance association virtually disappeared when the unpredictability contribution was partialed out, the fear/unpredictability correlation was only marginally affected when controlling for survival relevance. This suggests that nonrandomness of feared stimuli may result from the spatiotemporal unpredictability that is attributed to these stimuli. The current practice of using snakes and spiders as phobia-relevant, and flowers and mushrooms as neutral, cues was not justified by the ratings of the 15 independent experts.This study was supported in part by a grant from the Dutch Organization for Fundamental Research (ZWO/Psychon, 560-268-001).     

Risk and behavior: The mediating role of risk appraisal

The main issue of this paper concerns the mediating role of risk appraisal in the relation between past and future behavior. We expected previous risky behavior to heighten risk appraisal, which, in turn, should stimulate preventive behavior. Results ofthree tests of this mediation hypothesis showed that past behavior was strongly related to future behavior; people who behaved hazardously in the past indicated that they tend to do so in the future. Generally, the expected relation between past behavior and risk appraisal was supported. More risky behavior in the past was associated with a heightened risk appraisal. Results also indicate a relation between risk appraisal and future behavior, but in the opposite direction as predicted. Heightened risk appraisal was related to increased levels of risk in future behavior. When predicting future behavior by both risk appraisal and past behavior the effect of risk appraisal on future behavior disappeared, while past behavior remained a strong predictor of future behavior. In a few cases risk appraisal still predicted future behavior when past behavior was controlled for. Unfortunately, these cases showed the opposite relation; i.e., heightened risk appraisal was related to more risky future behavior. Implications of these findings for research on the role of risk appraisal will be discussed.     

No counterregulation after breaking the external restraint of children.

At the present, it is unknown how restraint and binge eating/counterregulation are exactly related. Earlier studies on this relationship suffer from two main shortcomings: the studies are all correlational in nature or could not rule out the contribution of confounding variables such as weight loss. The present study investigated whether a break of restraint is a sufficient condition for the occurrence of counterregulation by studying a restrained sample which is not liable to dieting practices and weight loss. The externally imposed restraint on children with regard to eating sweets was broken. However, after breaking their external restraint the children did not counterregulate. It is discussed whether restraint of food intake is really as important for binge eating as it is claimed to be or whether it is merely a consequence or an epiphenomenon of binge eating.     

Surface perception in pictures.

Subjects adjusted a local gauge figure such as to perceptually "fit" the apparent surfaces of objects depicted in photographs. We obtained a few hundred data points per session, covering the picture according to a uniform lattice. Settings were repeated 3 times for each of 3 subjects. Almost all of the variability resided in the slant; the relative spread in the slant was about 25% (Weber fraction). The tilt was reproduced with a typical spread of about 10 degrees. The rank correlation of the slant settings of different observers was high, thus the slant settings of different subjects were monotonically related. The variability could be predicted from the scatter in repeated settings by the individual observers. Although repeated settings by a single observer agreed within 5%, observers did not agree on the value of the slant, even on the average. Scaling factors of a doubling in the depth dimension were encountered between different subjects. The data conformed quite well to some hypothetical fiducial global surface, the orientation of which was "probed" by the subject's local settings. The variability was completely accounted for by single-observer scatter. These conclusions are based upon an analysis of the internal structure of the local settings. We did not address the problem of veridicality, that is, conformity to some "real object."     

Imputation of missing categorical data by maximizing internal consistency

This paper suggests a method to supplant missing categorical data by reasonable replacements. These replacements will maximize the consistency of the completed data as measured by Guttman's squared correlation ratio. The text outlines a solution of the optimization problem, describes relationships with the relevant psychometric theory, and studies some properties of the method in detail. The main result is that the average correlation should be at least 0.50 before the method becomes practical. At that point, the technique gives reasonable results up to 10–15% missing data.We thank Anneke Bloemhoff of NIPG-TNO for compiling and making the Dutch Life Style Survey data available to use, and Chantal Houée and Thérèse Bardaine, IUT, Vannes, France, exchange students under the COMETT program of the EC, for computational assistance. We also thank Donald Rubin, the Editors and several anonymous reviewers for constructive suggestions.     

Variations in characteristic perceptual asymmetry: modality specific and modality general components.

The current study investigates sources of between-subjects variation in asymmetry scores on visual half-field and dichotic listening tasks. For each of these presentation modalities, subjects were given multiple laterality tasks. Results indicate that about 50% of the between-subjects variations in asymmetry scores in each modality is attributable to individual differences in perceptual asymmetries that are not stimulus-specific, referred to as "characteristic perceptual asymmetries" in this paper. In addition, the question of whether individual differences in characteristic perceptual asymmetries are modality specific, modality general, or both was investigated by entering subjects' asymmetry scores from visual half-field and dichotic listening tasks into a principal component analysis. The results of this analysis indicate that there are both modality specific and modality general influences on subjects' characteristic perceptual asymmetries.     

The development of general competence and domain-specific competencies

The development of competence was studied in a longitudinal sample of 98 children, with measurement points when the children were 7, 10, and 12 years old. Competence was defined in terms of adequate adaptation to developmental tasks, both on a general and on a domain-specijic level. The general form of competence was measured by ego-resiliency, reflecting fexibility and ability to solve developmental problems Domain-specific competencies were measured by school achievement and social preference. The results showed that ego-resiliency was related to the two domain-specific competencies, although the hypothesized causal direction from general competence to specific competencies was not supported. Both domain-specific competencies were found to have a feedback effect on ego-resiliency. This feedback effect was stronger for social preference. These results suggest a transactional relationship between general and domain-specific competencies, and point to the importance of domain-specific competencies (especially social preference by the peer group) in the development of general competence in the child.