Coordinating Actions

The motor system composes complex actions by combining simpler submovements. This presumably involves sharing information about the progress of one submovement with the centres controlling another submovement, to ensure that the second happens in an appropriate relation to the first. This process is called coordination. In this paper Idiscuss evidence that coordinating actions indeed involves an active process of sharing information about the current state of movements. Coordination appears to be qualitatively different from the process of reacting to external stimuli. This may reflect the importance of predictive representations in coordination. Finally, the processes underlying coordination appear to be organized in a response-specific fashion, as a number of relatively independent circuits. The development and tuning of these circuits may, in part, be what makes an action "skilled".     

Book reviews

Encyclopaedia of Linguistics, Information and Control. Edited by A. R. Meetham with the assistance of R. A. Hudson. Oxford: Pergamon Press. 1969. Pp. xiv + 718. 300s.

The Biological Basis of Personality. By H. J. Eysenck. Springfield: Thomas. 1968. Pp. xv + 399. $18.50.

Scientific Basis of Dvug Dependence. Biological Council Symposium. Edited by H. Steinberg. London: Churchill. 1969. Pp. 429. 100s.

Minnesota Symposia on Child Psychology, Vol. 2. Edited by John P. Hill. Minneapolis: University of Minnesota Press. 1969. Pp. viii + 172.

Memory and Attention: an introduction to human information processes. By Donald A. Norman. Chichester, Sussex: John Wiley. 1969. Pp. ix + 201. 84s. (cloth); 44s. (paper). Verbal Learning and Memory: selected readings. By Leo Postman and Geoffrey Keppel. Harmondsworth: Penguin Books. 1969. Pp. 501. 12s.

Handbuch der Kinderheilkunde. Edited by H. Opitz and F. Schmidt. Rand VIII/I: Neurologie-Psychologic-Psychiatrie. Redigiert von F. Schmidt und H. Asperger. Berlin: Springer Verlag. Pp. 1060. Price DM385, S96.25.

Digital Computing. By R. S. Lehman and D. E. Bailey. London: John Wiley & Sons Ltd. 1969. Pp. xxiv + 303. 79s.

Real-Time Computers. By W. R. Uttal. New York: Harper & Row. 1968. Pp. xiv + 338. 93s.     

Book reviews

Animal Discrimination Learning. Edited by R. M. Gilbert and N. S. Sutherland. London: Academic Press. 1969. Pp. xvi + 501. 1358.

Luce, R. D. and Tukey, J. W. (1964). Simultaneous conjoint measurement: a new type of fundamental measurement. J. math. Psychol. I, 1-27.

Discrimination Learning. By D. A. Riley. Boston: Allyn and Bacon Inc. 1968. Pp. 172. Paperback 21s.

Annual Review of Psychology. Vol. 20. Palo Alto: Annual Reviews Inc. 1969. Pp. ix + 544. $9.00.

Cutaneous Sensation. By David Sinclair. London: Oxford University Press. 1967. Pp. xii + 306. 63s.

Modelling of Thinking and the Mind.. By N. M. Amosov. Translated by L. Finegold. New York: Spartan Books. London: Macmillan. 11967. Pp. xiii + 192.

The Mind of Mnemonist. By A. R. Luria. London: Jonathan Cape. 1969. Pp. xi + 160. 25s.

Determinants of Infant Behaviour IV. Edited by B. M. Foss. London: Methuen. 1969. Pp. 303. £3 10s.

Brain and Behaviour. Volumes 1-4. Edited by Karl Pribram. Harmondsworth: Penguin Books Ltd. 1969. Pp. 496 +573 + 523 + 524. 12s. 6d. per volume.     

Perception of voicing and place features in whispered speech: A dichotic choice analysis

To offset shortcomings of existing demonstrations of right-ear superiority in the analysis of formant transitions, an experiment was performed on whispered speech. Two aspects of dichotic listening performance were examined in a single-report paradigm: the right-ear advantage (REA) for the perception of the voicing distinction and the feature sharing advantage (FSA) for both voicing and place features. A significant REA was obtained for the voicing distinction cued by first formant transition in the absence of a switch from aperiodic to periodic excitation. This, plus a greater incidence of voiced responses to right-ear stimuli, suggests that a distinction involving transitions can specifically augment the REA. The data also showed better identification of place and of voicing feature values when the competing dichotic speech stimuli shared these respective features (FSA) than when they did not. This FSA was restricted to the feature shared and hence not an effect of response uncertainty. The implications of these results for models of speech processing are discussed.     

The perceived position of the hand in space

This paper reports a series of experiments of the perceived position of the hand in egocentric space. The experiments focused on the bias in the proprioceptively perceived position of the hand at a series of locations spanning the midline from left to right. Perceived position was tested in a matching paradigm, in which subjects indicated the perceived position of a target, which could have been either a visual stimulus or their own fingertip, by placing the index finger of the other hand in the corresponding location on the other side of a fixed surface. Both the constant error, or bias, and the variable error, or consistency of matching attempts, were measured. Experiment 1 showed that (1) there is a far-left advantage in matching tasks, such that errors in perceived position are significantly lower in extreme-left positions than in extreme-right positions, and (2) there is a strong hand-bias effect in the absence of vision, such that the perceived positions of the left and right index fingertips held in the same actual target position in fact differ significantly. Experiments 2 and 3 demonstrated that this hand-bias effect is genuinely due to errors in the perceived position of the matched hand, and not to the attempt at matching it with the other hand. These results suggest that there is no unifying representation of egocentric, proprioceptive space. Rather, separate representations appear to be maintained for each effector. The bias of these representations may reflect the motor function of that effector.     

The rubber hand illusion revisited: visuotactile integration and self-attribution

Watching a rubber hand being stroked, while one's own unseen hand is synchronously stroked, may cause the rubber hand to be attributed to one's own body, to "feel like it's my hand." A behavioral measure of the rubber hand illusion (RHI) is a drift of the perceived position of one's own hand toward the rubber hand. The authors investigated (a) the influence of general body scheme representations on the RHI in Experiments 1 and 2 and (b) the necessary conditions of visuotactile stimulation underlying the RHI in Experiments 3 and 4. Overall, the results suggest that at the level of the process underlying the build up of the RHI, bottom-up processes of visuotactile correlation drive the illusion as a necessary, but not sufficient, condition. Conversely, at the level of the phenomenological content, the illusion is modulated by top-down influences originating from the representation of one's own body.     

A cross-modal interference effect in grasping objects

The aim of the present paper was to investigate how the kinematics of a hand reaching toward a visual target would be influenced by haptic and proprioceptive input from an unseen distractor actively grasped in the other, nonreaching hand. The main results were that the amplitude of maximum grip aperture was smaller and the time to maximum grip aperture was earlier when the distractor was smaller than the target. The interference effect from the distractor was similar for both hands as they reached. Furthermore, results from a vibrating-distractor condition for passive tactile input revealed that the interference effects were evident only when the distractor was actively grasped. We suggest that neural processing of proprioceptive and tactile information relevant to distractor size produced the observed interference effects. We also emphasize the importance of active manipulation of the distractor stimulus in eliciting such interference effects.     

Effects of response type on coordinated responses during arm movement

This paper reports some experimental results on the coordination of finger and vocal responses with passing through a target position in multjjoint arm movement. In Experiment 1, we found that the difference in the timing of finger and vocal responses cannot be attributed entirely to efferent or representational effects. Instead, it appears to reflect the extent to which information about the internal stimuli generated by the arm movement are available to the centers controlling these different responses. That is, it is a compatibility effect. In Experiment 2, the case in which a finger response is made on the same side of the body as the moving arm was compared with the case in which it is made with the contralateral hand, which remains static. The interaction effect observed suggests that the path-ways subserving coordinated responses are informationally encapsulated, so that information about arm movement is not shared between the neural centers controlling different coordinated responses.     

Mentoring and Psychological Contract Breach

Purpose

Mentoring and psychological contracts are related and important organizationally based social exchange relationships. Research indicates that social support from internal mentors might buffer the negative effects of psychological contract breach (PCB), but less is known about the possible negative influence that mentors might have on psychological contracts. This study investigates protégés' perceptions of their mentors?? failure to fulfill mentoring obligations and protégés?? perceptions of PCB. Because either the formality of the mentoring relationship or the supervisory status of the mentor might serve as additional signals of the mentor??s status as an organizational agent, and, therefore, exacerbate the negative association between mentoring breach and PCB, both are investigated as potential moderating variables.

Design/Methodology/Approach

A sample of 144 protégés from various occupations completed a questionnaire assessing mentoring breach, PCB, job satisfaction and organizational commitment.

Findings

Results indicate the relations between mentoring breach and the outcome variables of interest were mediated by PCB, and that the relation between mentoring breach and PCB is stronger in supervisory mentoring relationships. A similar result was expected, but not confirmed, for formal mentoring relationships.

Implications

The current study provides evidence that the actions (or inactions) of mentors contribute to PCB and related negative outcomes. Such knowledge might encourage organizations to provide training to potential mentors in managing the mentoring relationship to minimize the probability of mentoring breach.

Originality Value

The current study is the first to examine the potential negative effect that mentoring relationships might have on protégé psychological contracts.