A note on the information-theoretic basis of Fitts' law

Fitts' law is an information-theoretic view of human motor behavior developed from Shannon's Theorem, 17, a fundamental theorem of communications systems. Using data from Fitts' original experiments, we demonstrate that Fitts' choice of an equation that deviates slightly from the underlying principal is perhaps unfounded, and that the relationship is improved by using an exact adaptation of Shannon's equation.     

The influence of sex bias upon compliance with expert power

The present study evolved from the belief that sex bias influences the degree of expert power which the expert has in relation to the perceiver. Therefore, the influence of level of expertise, sex of the expert, sex of the influencee, and sex domination of the expert's occupation upon compliance was examined. Separate experiments were conducted for the male- and female-dominated occupations. Subjects' degree of compliance was measured by their responses to three recommendations contained in an in-basket. The three-way analyses of variance revealed that only expertise significantly affected subjects' degree of compliance. Results are discussed in terms of the presence of outside recognition of competence and legitimate power.     

Visual movement perception: A comparison of sensitivity to vertical and horizontal movement

A psychophysical model that provides separate measures of judgmental standards and sensitivity is utilized to compare an O’s visual sensitivity for vertical and horizontal movement. The analysis indicates no consistent difference in sensitivity; those asymmetries that do exist simply appear to be due to idiosyncratic judgmental standards.     

In search of personality traits: A multimethod analysis of naturally occurring prosocial and dominance behavior

Naturally occurring prosocial and dominance behaviors were observed via multiple methods in four groups of adolescents. Individuals varied considerably in their frequency of prosocial and dominance behaviors, regardless of the method employed. These interindividual differences were maintained across situations and over time. The data are consistent with a trait conceptualization of dominance and prosocial behavior. The strength of the present findings suggest that personality researchers need to employ research strategies which extensively observe individuals in the contexts in which they live.     

Social skills training: the generalisation problem—some further data

In a previous short report the author described a pilot investigation into the effectiveness or a Social Skills training group for chronic patients in a psychiatric day hospital. (Shepherd, 1977). The results were not encouraging and there is still a shortage of evidence from controlled trials concerning the effectiveness of social skills training with clinical populations (Hersen and Bellack, 1976). These authors also comment on the tendency to ignore the problem of how to generalise treatment gains from one setting to another and the failure to incorporate generalisation procedures into treatment programmes.Our own preliminary findings caused us to make a number of changes in procedure. These may be summarized as: (1) an increase in the duration and frequency of treatment sessions, (2) a much greater emphasis on setting targets, organising reinforcements, and even conducting complete sessions, in contexts other than the treatment group, and (3) a greater attempt to take account of individual differences and their influence on treatment outcome. In this connection it seemed important to acknowledge the role of cognitive factors in social problems (Nichols, 1974), and also the special learning difficulties of schizophrenic patients as highlighted by the recent research on their information-processing deficits (Hemsley, 1977). The details of these changes in technique and a fuller discussion of their theoretical rationale can be found in Shepherd (1978). The present paper reports the results of a second trial using these modified procedures.     

Sex-role identity,sex of other,and affective relationship as determinants of interpersonal conflict-management styles

Previous research in sex-role identity has explored behavioral differences in a variety of contexts. Only recently, however, have differences in interaction style been investigated. The study reported here was designed to assess behavioral differences in one important type of interaction: interpersonal conflict. Of 143 college students responding to the Bem Sex-Role Inventory (BSRI), a final sample of 57 subjects provided questionnaire data on five conflict-management modes in hypothetical conflicts with others who varied on factors of sex and affective relationship with respondent. Results of the MANOVA analysis suggested that feminine persons disapprove of competition more than persons of masculine and androgynous sex-role identification. The results further suggested that masculine persons may differentiate less between liked and disliked others in their competitive behavior than do feminine and androgynous persons. Finally, results suggested that conflicts with liked, as opposed to disliked, others are managed with less competition and more accommodation, collaboration, and compromise for all sex-role identity groups.     

Influence of aging on recovery from aphasia in polyglots

We analyzed patterns of recovery, according to the rules of Pitres [1895, Revue de Medecine (Paris), 15, 873–899] and Ribot (1881, Les Maladies de la Memoire, Paris: Libraire Germer Baillere et Cie, pp. 146–147), in polyglot aphasics divided into subgroups by age. The rule of Ribot did not apply predictably for any age group. Pitres' rule clearly applied, but only for the nonelderly groups. Aging and its concomitant deterioration of recent memory seem to influence patterns of recovery from aphasia in polyglots.     

Similarity effects in face recognition

Three experiments are described which examine the effects of similarity on face recognition using a new application of hierarchical clustering analysis (HCS). Experiments I and II employed a within-groups design where subjects attempted to recognize targets among decoys from the same and different cluster to the target. Common cluster membership accounted for 72% and 84%, respectively, of all false alarms in the two experiments. Absolute error rates were affected by the number of targets actually present in the array and the style of the instructions given to subjects but were not influenced by whether successive or simultaneous test presentation was employed. Experiment III used a between-subject design where targets were embedded in arrays composed from same or different clusters. False alarm rates were significantly higher for the same cluster condition, but hit rates were unaffected by recognition context. The significance of these findings for theories of face identification is discussed.     

The effects of object weight on the kinematics of prehension

The purpose of these experiments was to determine the effects of object weight and condition of weight presentation on the kinematics of human prehension. Subjects performed reaching and grasping movements to metal dowels whose visible characteristics were similar but whose weight varied (20, 55, 150, 410 g). Movements were performed under two conditions of weight presentation, random (weight unknown) and blocked (weight known). Three-dimensional movements of the thumb, index finger, and wrist were recorded, using a WATSMART system to obtain information regarding the grasp and transport components. The results of the first experiment indicated that object weight and condition of presentation affected the temporal and kinematic measures for both the grasp and transport components. In conjunction with the results of a second experiment, in which time in contact with the dowel was measured, it was shown that the free-motion phase of prehension (i.e., up to object contact) was invariant over the different conditions, however. The changes were observed in the finger-object interaction phase (when subjects applied forces after contact with the dowel), prior to lift-off. These results were interpreted as indicating (a) object weight does not influence the planning and execution of the free-motion phase of prehension and (b) there are at least two motor control phases involved in prehension, one for making contact with the object and the other for finger-object interaction. The changing contributions of visual, kinesthetic, and haptic information during these two phases is discussed.