Orienting the finger opposition space during prehension movements

Two experiments are reported that examined the act of prehension when subjects were asked to grasp with their thumb and index finger pads an elongated object resting horizontally on a surface and placed at different orientations with respect to the subject. In Experiment 1, the pad opposition preferences were determined for the six angles of orientation examined. For angles of 90 degrees (object parallel to frontal plane) or less, no rotation of the wrist (pronation) was used; for angles 110 degrees or greater, pronation was systematically employed to reorient the finger opposition space. Only one angle, 100 degrees , produced any evidence of ambiguity in how to grasp the object: Approximately 60% of these grasps involved pronation and 40% did not. Using the foregoing grasp preference data, in Experiment 2 we examined the kinematics of the wrist and elbow trajectories during prehension movements directed at an object in different orientations. Movement time, time to peak acceleration, velocity, and deceleration were measured. No kinematic differences were observed when the object orientation either required (110 degrees ) or did not require (80 degrees ) a pronation. By contrast, if the orientation was changed at the onset of the movement, such that an unpredicted pronation had to be introduced to achieve the grasp, kinematics were affected: Movement time was increased, and the time devoted to deceleration was lengthened. These data are interpreted as evidence that when natural prehension occurs, pronation can be included in the motor plan without affecting the movement kinematics. When constraints are imposed on the movement execution as a consequence of a perturbation, however, the introduction of a pronation component requires kinematic rearrangement.     

Pharmacological dissociation of memory: anisomycin, a protein synthesis inhibitor, and leupeptin, a protease inhibitor, block different learning tasks

Inhibition of protein synthesis by anisomycin for a short duration impairs memory of a one-trial inhibitory avoidance task in rats. Memory of escape conditioning involving eight trials is disrupted only if the duration of protein synthesis is prolonged by repeated injections. In marked contrast, olfactory memory of rats trained on two odor discriminations is not affected by anisomycin even if the duration of inhibition is prolonged and the number of trials is reduced to a minimum. In previous work, leupeptin, a thiol proteinase inhibitor, was shown to impair olfactory discrimination learning, but left inhibitory and avoidance conditioning intact. Together, these results provide a pharmacological double dissociation of memory, and suggest that the same chemistries, or mixtures of chemistries, may not be involved in all types of memory.     

Social facilitation during the initial stage of motor learning: a re-examination of Martens' audience study

This study partially replicated Martens' (1969a) social-facilitation study of motor behavior. His very robust performance findings provided impressive confirmation for Zajonc's hypothesis, and his arousal findings have since been used as evidence for a nonlearned-drive basis for social facilitation. The present study also extended Martens' investigation by examining the separate and combined effects of an audience and videotape camera. The effects due to the presence of the audience and camera were not additive; instead, the audience detrimentally affected subjects' performance consistency and the camera resulted in more trials with errors greater than 30 msec after the performance criteria had been attained. Martens' most robust findings for constant error were not replicated, nor were some of his physiological arousal findings. His pattern of constant error results over all trials is atypical of known learning strategies that subjects use to reduce error over successive trials. Overall, audience effects accounted for only a very small portion of the variance.     

Differential indications for desipramine--results of a controlled multiclinical study]

The antidepressants desipramine and imipramine were compared within the framework of a multiclinical study performed under the conditions of a controlled clinical experiment. There has been found a time-different remission of affective symptoms, which was not detectable for the inhibition of drive. The tachythymoleptic action of desipramine is discussed with reference to these results. Evaluation of the possibility of controlling affects shows different ranges of activity of desipramine and imipramine, with desipramine influencing especially negative psychoenergetic symptoms in the area of drives and emotions and imipramine, restrictive symptoms in addition to differential phenomena of the psychomotor expression.     

Barriers to Adult Career Change

Adults have unique problems in making career changes. They face crucial economic, educational, and psychological barriers that require special guidance services. In this article, barriers to adult career change are identified and a five-county regional learning service using paraprofessionals is described. Results in working with more than 200 adults making career changes is reported. Suggestions for overcoming some of the problems adults face in making career changes are explained.     

A vector graphic CRT display system

A vector graphic CRT display system for research in visual information processing is described. The vector graphic processor includes a 4K-byte display memory. The processor communicates with the controlling computer via a serial channel. The system is capable of exposure durations below 1 msec, and it allows on-line generation and modification of display files during an experiment. Brightness can be controlled separately for each vector of a picture. A graphic display editor in FORTRAN IV for interactive editing and debugging of display files has been developed.     

Irrelevant differences in the "same"--"different" task

This article examines the effects of irrelevant information on the multidimensional "same"--"different" task. Subjects were instructed to compare two geometric figures with respect to certain attributes but to ignore other attributes in making the "same"--"different" decision. The irrelevant attributes were chosen in such a way that they could not easily be ignored to see how the existence of irrelevant differences would affect the comparison process. As expected, the overall latencies were longer than is usually found in tasks with no irrelevant differences. However, the nature of the comparison process appeared unchanged. The usual finding of a "fast-same" phenomenon persisted even when irrelevant information was present. The similarity of the results in this task to results in the "same"--"different" task with no irrelevant features supports the idea that the same comparison mechanism is used whether or not irrelevant differences are present in the stimulus pairs. The results suggest a more general-purpose comparison mechanism than is usually included in models of this task. Two-process models of visual comparisons are thus ruled out entirely. A modified version of Krueger's noisy-operator theory does appear consistent with the results.     

Perception of American sign language in dynamic point-light displays

Perception of dynamic events of American Sign Language (ASL) was studied by isolating information about motion in the language from information about form. Four experiments utilized Johansson's technique for presenting biological motion as moving points of light. In the first, deaf signers were highly accurate in matching movements of lexical signs presented in point-light displays to those normally presented. Both discrimination accuracy and the pattern of errors were similar in this matching task to that obtained in a control condition in which the same signs were always represented normally. The second experiment showed that these results held for discrimination of morphological operations presented in point-light displays as well. In the third experiment, signers were able to accurately identify signs of a constant handshape and morphological operations acting on signs presented in point-light displays. Finally, in Experiment 4, we evaluated what aspects of the motion patterns carried most of the information for sign identifiability. We presented signs in point-light displays with certain lights removed and found that the movement of the fingertips, but not of any other pair of points, is necessary for sign identification and that, in general, the more distal the joint, the more information its movement carries.     

A two-year follow-up study of a preventive mental health program for preschoolers

The long-term effects of a preschool intervention program for high-risk experimental children were assessed and compared to a high-risk placebo control group and low-risk normal controls. Seventy first-grade children were involved in this 2-year follow-up. The experimental treatment group was superior to that of the placebo control group at follow-up on the criteria measures of behavioral adjustment and achievement. The low-risk normal control group was significantly different from that of the placebo control groups, but generally not significantly different from that of the experimental groups, suggesting that the intervention had boosted the high-risk experimental treatment children to the point where their performance was comparable to that of children who had not experienced behavioral or learning difficulties.The study was supported by grants from the McGregor Fund and the Eloise and Richard Webber Foundation, and by the Detroit Public Schools, for which the authors express grateful appreciation. A version of this paper was presented at the Annual Meeting of the American Psychological Association, New York, September 1979.     

The treatment of epilepsies with Convulsofin

The testing of Convulsofin carried out in 220 patients at 14 clinics over a period of six months confirms the international experience gained with valproic acid and sodium valproinate. The main field of application of Convulsofin according to the experience gained will again be the treatment of fits in generalised primary epilepsy for which it permits to carry out a monotherapy to a remarkable extent. The favourable effect of the preparation in photosensitivity could be confirmed. Also in generalised secondary epilepsy and in fits of partial epilepsy. Convulsofin is partly effective, so that it can recommended as a co-medication in the treatment of therapy-resistant forms of these epilepsies which are difficult to treat. Decrease in thrombocytes, transient increase in serum transaminases, gastrointestinal disorders, loss of hair and undesired increases in body-weight were the more frequently occurring side-effects.