Reviews

The Gulag Archipelago (Vols. 1 and 2) by Alexander Solzhenitsyn, Collins, 1974 and 1975, 600 pp. and 712 pp. £3.50 and £4.95.

Arkhipelag Gulag (Vols. 1, 2 and 3) YMCA Press, Paris, 1973, 1974 and 1976, 606 pp., 657 pp. and 581 pp. No price.

A Marxist Looks at Jesus by Milan Machovec, Darton Longman & Todd, 1976, 220 pp. £2.95.

White Book on Restrictions of Religion in the USSR by Michael Bourdeaux, Committee for the Defence of Human Rights in the USSR, Brussels, 1976, 66 pp., 65p.

Religious Liberty in the Soviet Union: WCC and USSR—A Post‐Nairobi Documentation edited by Michael Bourdeaux, Hans Hebly and Eugen Voss, Keston College (CSRC), 1976, 96 pp., £1.50.     

Modeling the Neurological Control of Human Movements

Although computer models have been extensively used in recent years to understand the way physical systems operate and interact, the enormous power of mathematical modeling and computer simulations has been difficult to implement for the benefit of neuroscientists studying the human motor control system. Nevertheless, homeomorphic models are now being used to explain and predict the neural and biomechanical aspects of different human movements. This paper argues for the importance of regarding model simulations as a supplementary approach to traditional methods of experimental investigation by drawing examples from both the experimental and the modeling literature. The discussion focuses on studies of the triphasic control signal for fast, goal-directed movements and on aspects of sampled data control for slow, tracking movements. The aim of this viewpoint article is to promote a more widespread use of modeling and simulation in the field of motor control.     

Selling and Sales Management in Action: Sales Training: Status and Needs

Initial training, continuing education and management development activities continue to receive attention in the industrial sector (Honeycutt and Ford 1991). For example, recent reports indicate that organizations spend upwards of $30 billion annually for training programs involving 15 billion work hours (Huber 1985), with the objective being to improve the profitability of the firms.     

Grasping spheres,not planets

Memory for objects helps us to determine how we can most effectively and appropriately interact with them. This suggests a tightly coupled interplay between action and background knowledge. Three experiments demonstrate that grasping circumference can be affected by the size of a visual stimulus (Experiment 1), whether that stimulus appears to be graspable (Experiment 2), and the presence of a label that renders that object ungraspable (Experiment 3). The results are taken to inform theories on conceptual representation and the functional distinction that has been drawn between the visual systems for perception and action.     

Temporal control of internal states in pigeons

To understand how animals serially organize complex competing behaviors, we tested pigeons in a sequential task-switching procedure. Daily sessions involved two conditional discrimination tasks that were presented in sequence. In Experiment 1, the first half of a session employed a matching-to-sample task, and the second half tested an oddity-from-sample task. Because the same colors were used for both tasks, these tasks could be solved only by employing a modulating sequential cue. The results of the first experiment revealed that the pigeons could learn this task-switching procedure and that an internal clock was the critical modulator between the tasks. In Experiment 2, we tested a three-alternative choice task. By examining the pattern of errors among choices, the results of this experiment revealed that pigeons learned and used different representations of the choice rules for each half of the experiment. This modulation of the pigeons’ internal states by time has implications for how animals organize their behavior in different settings and holds clues as to the evolution of the serial organization of behavior.