Grip strength and fatigue in junior college tennis players.

Change in grip strength over 30 trials was documented in two samples of junior college tennis players to assess possible fatigue. Eight men and eight women performed 30 maximum-grip strength tests with 25-sec. rests between trials. Significant positive correlations (.38 and .53 for men and women) were observed between grip strength and trials. In practical terms, grip strength did not change over 30 trials in these tennis players. The data suggested that the repetitive gripping patterns used by these players in tennis play resulted in consistent maximum-grip strengths across 30 trials.     

Our Eyes Do Not Always Go Where We Want Them to Go: Capture of the Eyes by New Objects

Observers make rapid eye movements to examine the world around them. Before an eye movement is made, attention is covertly shifted to the location of the object of interest. The eyes typically will land at the position at which attention is directed. Here we report that a goal-directed eye movement toward a uniquely colored object is disrupted by the appearance of a new but task-irrelevant object, unless subjects have a sufficient amount of time to focus their attention on the location of the target prior to the appearance of the new object. In many instances, the eyes started moving toward the new object before gaze started to shift to the color-singleton target. The eyes often landed for a very short period of time (25–150 ms) near the new object. The results suggest parallel programming of two saccades: one voluntary, goal-directed eye movement toward the color-singleton target and one stimulus-driven eye movement reflexively elicited by the appearance of the new object. Neuroanatomical structures responsible for parallel programming of saccades are discussed.     

Social values and cooperative response to a simulated resource conservation crisis

The present study examined the relationship between individuals social motives or values and their level of cooperation during a simulated resource conservation crisis Prior to the resource task, a decomposed game procedure was used to classify subjects as cooperatively or noncooperatively oriented Subjects, in groups of six, were led to believe that they shared access to a replenishing resource pool via a system of linked computer terminals Across a series of trials, subjects had to choose between maximizing their own short-term gain and exercising personal restraint to preserve the collective resource False feedback about the group's use of the resource and the rate at which it was replenished was varied to indicate either that the resource was being sustained or that collective overuse was rapidly depleting it As predicted, cooperatively oriented individuals responded to resource depletion with greater self-restraint than did those classified as noncooperators Analvsis of pretrial and posttrial data indicated that social values were also related to individuals expectations about the task and perceptions of others     

WISCONSIN MANPOWER COUNSELORS AND MANPOWER SPECIALISTS' PERCEPTIONS OF EXISTING AND DESIRED COUNSELOR ACTIVITIES

Seventy-three counselors and 72 manpower specialists in Wisconsin were surveyed to ascertain the perceptions both groups had regarding actual and ideal counselor function. A cross-break analysis to determine if responses varied according to years in the employment service, office size, and educational background produced no differences. Counselors and manpower specialists were in close agreement. (Rho .96) in ranking the time assigned to 12 functions by the counselor and were closely agreed (Rho .94) in ranking how counselors should spend their time. Other similarities and differences were presented followed by a discussion of the implications these findings have for in-service training.     

Untersuchungen und Überlegungen zur Richtungswahrnehmung bei willkürlichen sakkadischen Augenbewegungen

Zusammenfassung Die vorliegende Arbeit hatte das Ziel, die Umstimmung der retinalen Raumwerte während willkürlicher horizontaler Blicksprünge (Sakkaden) zu untersuchen.Die Methodik bestand darin, während oder nach der Augenbewegung kurzzeitig einen ca. 1° großen Lichtreiz (Elektronenblitz) im Gesichtsfeld der Vp zu exponieren, den diese in bezug auf eine kopffeste Skala zu lokalisieren hatte. Die Auslösung des Lichtreizes erfolgte auf elektrookulographischem Weg durch die Augenbewegung selbst.Bei diesen Versuchen traten in systematischer Abhängigkeit vom retinalen Ort des Reizes und von der zwischen Sakkadenbeginn und Reizexposition verstrichenen Zeit deutliche Verlagerungstäuschungen auf. Sie lassen sich am besten interpretieren, wenn man die Umwertungsprozesse als Wanderung eines lokalisatorischen Bezugssystems über ein zentralnervöses Projektionsfeld der Retina auffaßt. Diese Wanderung wird eingeleitet und angeführt durch ein rasches Einschwingen der Koordinate des Zielpunktes der Blickbewegung in die Fovea; in der zielabgekehrten Netzhauptperipherie vollzieht sich die Umwertung wesentlich langsamer. Dabei kann es vorübergehend zu topologischen Veränderungen des Bezugssystems kommen, deren Genese noch unklar ist.Ausgehend von den bislang vorliegenden Ansätzen zur Erklärung der Richtungskonstanz (insbesondere vom Reafferenzprinzip, den Aufmerksamkeitstheorien und der Theorie MacKays) wird ein eigenes Modell entwickelt, in dessen Rahmen die Versuchsergebnisse diskutiert werden.

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Investigations and considerations of directional perception during voluntary saccadic eye movements

Summary This investigation attempts to examine the change of retinal local signs during voluntary horizontal saccadic eye movements. The method used was to expose the S. to a short light stimulus (electronic flash) of approximately one degree angular width during or after a 16 degree eye movement. The stimulus was released by the eye movement itself via the retino-corneal potential. The S.'s task was to localize the stimulus on a fixed luminous scale.Clear translatory illusions occurred in these experiments. They depended systematically on the spot on the retina stimulated, and on the time elapsed between the onset of the saccade and the release of the stimulus. These illusions are best interpreted as due to the shift of a coordinate system across the retinal field. The shift is initiated by the coordinate of the retinal spot on which the target of the eye movement was projected before the saccade began. This coordinate rapidly swings into the fovea. The processes on the retinal hemisphere opposite to the target occur at a much slower rate. Moreover, temporary changes of the topology of the coordinate system may take place during the saccade. Their origin is still unclear.The results of the experiments are discussed in terms of a special model based on the previous explanations of the phenomenon of directional constancy (especially the reafference principle, the attention theories, and MacKays theory).

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Diese Arbeit wurde mit Unterstützung der Deutschen Forschungsgemeinschaft ausgeführt. Wir danken unseren Versuchspersonen für ihre ausdauernde Mitarbeit sowie Frau Dipl.-Psych. Doris Bischof, Herrn Peter Heinecke und Frau Dr. Maria V. Schaetz für ihre Hilfe bei der Durchführung und Auswertung der Versuche.