The kinematics,movement phasing and timing of a skilled action in response to varying conditions of uncertainty

This study was designed to provide a detailed analysis of the parameters which interact to produce a field hockey drive. The drive was performed by an elite performer under two conditions of uncertainty (Blocked and Random). The subject was asked to drive a field hockey ball toward a specified target. In the Blocked condition the speed of the approaching ball remained constant (20, 30 and 40 m.p.h.) while in the Random condition these speeds were randomly assigned to each trial. Cine analysis of the subject's successful responses under the two experimental conditions led to an investigation of the kinematics, phasing, and timing of the stroke. The subject placed emphasis upon varying the initial phases of the stroke (i.e., backswing and preparatory phases) in order to produce a temporally consistent ballistic downswing to ball contact. It seemed likely that the subject appraised the ball speed that was being delivered and then incorporated additional stick movement to ‘mark time’ before initiating temporally consistent movement phases, as spatial uncertainty increased, the subject delayed her response initiation, but then tended to respond in intervals of one reaction time for each stroke phase. Consistency was evident for displacement and initiation point values, but to a lesser extent than existed for the other variables. However, as a result of this adjustment in spatial location and displacement of the stick end during the preliminary phases of the response, the subject was able to produce a consistent and accurate ballistic downswing.     

Figurai vs. configural effects in the filled duration illusion

Patterns varying in form goodness and size were presented for 15, 30, and 45 msec. The experiment included three independent groups of subjects. Half of the first group were presented size variations with good figures, while the other half were shown size variations with poor figures. Half of the second group were presented goodness variations with small figures, while the other half were shown goodness variations with large figures. A third group experienced variations in both goodness and size. The major findings were: (1) poor figures and large figures were judged “longer” than good or small figures when varied within a session; (2) this effect vanished when the different levels of size or goodness were presented to separate groups of subjects; (3) the magnitude of the difference in temporal estimation was the same for size and goodness when each was varied in isolation; (4) when size and form goodness were varied orthogonally in the same session, both dimensions produced reliable changes in temporal estimation. These data are discussed in light of current theoretical explanations of the filled duration illusion.     

The morphological asymmetry of the hemispheres and cerebral dominance for speech: A possible relationship

The asymmetry of the posterior Sylvian branches of the middle cerebral artery was examined on the carotid angiograms of 59 patients in whom the lateralization of speech representation was known from sodium amobarbital (Amytal) studies. The usual asymmetry of these vessels was found to be present in the group of patients with left-hemisphere speech representation but significantly reduced in patients with atypical cerebral dominance for speech. A model of the inheritance of handedness and cerebral dominance is extended to take account of these results.     

A reexamination of sex differences in job preferences

Previous research has found conflicting answers to the question of whether males and females share similar preferences for various job characteristics. It is difficult to determine if the different findings are due to the different populations sampled, the various methodologies employed, or to a real change in the phenomenon itself. This study essentially replicates earlier work by having 130 male and 84 female college students rate the importance of 10 job characteristics for both themselves and members of the opposite sex. Both sexes rated motivators as important, but females also placed importance on the hygienes. Males tended to underestimate the importance of the motivators for females, while females overestimated the importance of hygienes for males. The subject's sex could be predicted by both the importance for self and importance for opposite sex ratings, contrary to the earlier study. The difference in results and interpretation was shown to be due to the type of analyses used. Additionally, it was found that females' job preferences were related to their mothers' educational achievement.     

Incorporating inferences in narrative representations: A study of how and why

Four experiments examined the conceptual organization of narrative passages and the extent to which these representations were explanatory in a variety of experimental tasks. The conceptual representation of a passage consisted of a graph of labeled nodes and labeled, directed arcs which were adopted from the Conceptual Dependency Theory. These representations included both explicitly stated information and inferences which had been empirically extracted by a question-answering procedure. Symbolic procedures for answering how- and why-questions were also delineated. The conceptual representations and the symbolic procedures that operate on these representations together accounted for 91% of the answers generated from question-answering protocols in Experiment 1, and also the rated quality of specific answers to specific questions in Experiment 2. Experiments 3 and 4 supported the hypothesis that structural properties of the representations can predict recall of explicitly stated nodes and verification ratings of inference nodes. The results provide encouraging support for the proposed graphic representations and also for the use of question-answering protocols in uncovering prose inferences.     

Social influence processes affecting adolescent substance use

Social influence is central to models of adolescent substance use. Nonetheless, researchers fail to delineate the various forms of social influence. A framework that distinguishes between active (explicit drug offers) and passive (social modeling and overestimation of friends' use) social pressure was tested. The effect of these processes on alcohol and cigarette use was examined with 526 seventh graders taking part in an alcohol prevention program. Hierarchical regression analyses demonstrated that pretest measures of alcohol use, offers, modeling, and overestimation each accounted for unique variance in posttest alcohol use. Similar results were obtained for cigarette smoking. The general model was not significantly different for boys and girls, or for prior users and prior nonusers, supporting the generalizability of the framework. Implications for intervention programs are discussed.     

Three methods of developing MMPI taxonomies of sexual offenders

In a sample of 261 state hospital sexual offenders, Minnesota Multiphasic Personality Inventory (MMPI) profiles did not differ for offenders with adult victims versus offenders with child victims when offender age was controlled. MMPI 2-point analyses for the whole sample revealed five common codes that were independent of victim maturity. The sample was randomly divided in half and subjected to a cluster-analytic procedure which revealed two MMPI clusters. The first cluster was unelevated, with Scale 4 as its high point. The second cluster had multiple elevations, with Scales 8, 4, 2, and 7 as the highest scales. These clusters were replicated in a cluster analysis of the second half of the sample. However, when the sample was recombined, the two clusters were not externally validated basis on demographic and criminological variables. The results suggest that common psychological variables among sexual offenders may have more discriminative value than victim maturity in developing sexual offender taxonomies.