Common response processing and psychological refractoriness

This experiment examined whether structural considerations, that is the functional closeness of limb control centres (Kinsbourne and Hicks 1978), have a role to play in common processing models of psychological refractoriness. A typical double stimulation paradigm was used (Kantowitz 1974). On experimental trials, subjects responded with the right hand (RT1) to an auditory signal (0.80 probability). After a varied interstimulus interval (ISI) of 100, 200, 300 or 700 msec, one of three lights corresponding to one of the other limbs provided the signal for the second response (RT2). Control trials for RT1 and RT2 involved both stimuli, but subjects were required to make only one response. Results indicated that experimental RT1 was lengthened considerably over control values. While typical double stimulation effects were found at short ISIs, that is RT2 was lengthened, RT2 at long ISIs was actually faster than double stimulation control values. Although the RT results were not in a pattern that would be predicted by functional distance (Kinsbourne and Hicks 1978), within subject correlations of RT1 and RT2 by limb condition suggest that structural considerations may have a role to play. While within subject correlations were positive at all levels of ISI, they decreased as the interval between the two signals increased. The implications of these results for common processing models are discussed.     

The significance of unusual acts in sexual homicide

In addition to being an unusual form of crime, sexual homicide (SH) sometimes includes unusual crime scene behaviours, such as carving on the victim, evisceration (i.e., removal of internal organs), skinning the victim, cannibalism and vampirism. The current study investigates these unusual crime scene behaviours to better understand their meaning as well as to explore whether such behaviours are associated with a specific crime-commission process. Using a sample of 762 SH cases, the study uses a combination of chi-square and stepwise forward logistic regression analyses to identify the differences between cases with and without unusual acts. Findings reveal that SH cases with unusual acts present a specific crime-commission process. This crime-commission process is characterised by a greater level of sadism—as demonstrated by the presence of mutilation and foreign object insertion—as well as a greater level of organisation from the selection of a contact location where the risk of being seen or heard was low. These findings provide a better understanding of these behaviours and could help investigators facing such cases.     

The relation between hierarchical and euclidean models for psychological distances

In one well-known model for psychological distances, objects such as stimuli are placed in a hierarchy of clusters like a phylogenetic tree; in another common model, objects are represented as points in a multidimensional Euclidean space. These models are shown theoretically to be mutually exclusive and exhaustive in the following sense. The distances among a set ofn objects will be strictly monotonically related either to the distances in a hierarchical clustering system, or else to the distances in a Euclidean space of less thann — 1 dimensions, but not to both. Consequently, a lower bound on the number of Euclidean dimensions necessary to represent a set of objects is one less than the size of the largest subset of objects whose distances satisfy the ultrametric inequality, which characterizes the hierarchical model.This work was supported in part by Grant GB-13588X from the National Science Foundation. I would like to thank L. M. Kelly and A. A. J. Marley for their helpful comments and suggestions.     

The effects of test anxiety, sex of subject, and type of verbal reinforcement on maze performance of elementary school children

The purpose of this study was to account for children's performance in an educational setting by evaluating individual difference factors and the subjects' differential responsivities to social reinforcement The child subjects performed on Porteus mazes, which were viewed as complex, stress-inducing tasks They were differentiated in terms of sex and test anxiety levels. Each child received the same number of noncontingent reinforcements, which consisted of either verbal praise or verbal criticism or no feedback The data yielded significant triple interaction effects among anxiety, sex, and social reinforcement for the time and error scores on the mazes The data were discussed in terms of their implications for remediating performance in educational settings and their support for the theoretical conception of test anxiety as a chronic drive state The authors concluded that the extrinsic, motivating effects of verbal reinforcement can be reasonably characterized, but only if one attends to individual differences among those subjects being reinforced.     

Reaction time as a function of the intensity and probability of occurrence of vibrotactile signals

Three Ss made judgments of the presence or absence of a burst of 60-cps vibration onthe index fingertip.The probability of S’s reporting the presence of a signal was found to be influenced by signal probability and signal intensity. Mean reaction time for reporting the presence of a signal decreased as a function of signal intensity and signal probability whereas mean reaction time for reporting the absence of a signal increased as a function of signal intensity and signal probability. On trials where no signal was presented mean R T for reporting a signal decreased with increases in the signal probability whereas mean RT for reporting the absence of a signal increased with increases in signal probability. The results were interpreted as support for the hypothesis that S’s decision time was longer the closer on the sensory continuum a particular observation was to his criterion.     

The number of ways to label a structure

It has been observed that the number of different ways in which a graph withp points can be labelled isp! divided by the number of symmetries, and that this holds regardless of the species of structure at hand. In this note, a simple group-theoretic proof is provided.This work was supported by Grant MH 10834 from the National Institute of Mental Health.     

Psychometric properties and factor structure of the Fear Questionnaire phobia subscale items in two normative samples

Normative data for the Fear Questionnaire (Marks & Mathews, 1979), a popular self-report instrument measuring phobic concerns, were collected from both a community and a collegiate sample. The covariation and internal consistency of the blood-injury phobia (BI), social phobia (SO), and agoraphobia (AG) subscales were assessed in each sample, and the factor structure of the items from these three subscales was examined. Results indicated that, in general, community subjects reported more phobic concerns than did collegiate subjects, and females reported greater phobic concerns than did males. Results from confirmatory factor analyses suggest that the three factors of BI, SO, and AG did not emerge from either data set. Follow-up exploratory factor analyses did identify the general factors of blood-injury phobia and agoraphobia. Normative data from the present study are compared to those obtained previously, and directions for future research are provided.     

VSearch: Macintosh software for experiments in visual search

In this paper, we describe software that turns a Macintosh computer into an off-the-shelf tool for experiments on visual search. Our design goals included portability (between members of the Macintosh computer family and between various research settings), user-friendliness (equivalent to Macintosh programming standards), flexibility (to allow replication and extension of important experiments on visual search), and adaptability (very short design-to-data and data-to-analysis turnaround times). We describe how the software meets these goals in three major phases of an experiment: stimulus construction, experimental control, and statistical analysis. We then list several landmark studies of visual search that can be easily designed and extended with the software. Finally, we outline plans for expanding the experimental variations that will be supported in future versions of the software.