Effect of bandwidth knowledge of results on the learning of a grip force control task

An experiment was conducted to investigate the persistence of the effect of "bandwidth knowledge of results (KR)" manipulated during the learning phase of performing a manual force-control task. The experiment consisted of two phases, an acquisition phase with the goal of maintaining 60% maximum force in 30 trials, and a second phase with the objective of maintaining 40% of maximum force in 20 further trials. There were four bandwidths of KR: when performance error exceeded 5, 10, or 15% of the target, and a control group (0% bandwidth). Analysis showed that 5, 10, and 15% bandwidth led to better performance than 0% bandwidth KR at the beginning of the second phase and persisted during the extended trials.     

Insanity and responsibility

This paper attempts to set forth, in the context of Anglo‐U.S. criminal law, the meaning of the concept of insanity, its necessary relation to absence of responsibility, and its bearing on some relevant psychiatric concepts and legal controversies. Irrationality is a distinctive and necessary (but not sufficient) condition for insanity. Irrationality consists in failure even to grasp the relevance of what is ‘essentially’ relevant. To that extent there obviously can be no responsibility. A mental makeup which renders one (who would not normally be so) substantially incapable of rational conduct constitutes insanity, and in that respect renders the person non‐responsible. Much more broadly and roughly speaking, the mind that is ill is the mind that is irrational (and hence in that respect non‐responsible).     

Election predictions: Reply

Contrary to Aubert's claim, my paper on election predictions does not seek to draw empirical conclusions from mathematical premisses alone. The empirical premiss, approximated by the continuity assumption, is that sufficiently small changes in the predicted vote will cause only small changes in the actual vote. The technical criticisms by Øfsti and Østerberg of the reaction function are answered by specifying the function's domain. Other criticisms are also answered, and the reply concludes by placing the election prediction theorem in the context of other theorizing about human expectations and outguessing phenomena.     

The Deaf and Their Problems by Kenneth W. Hodgson

Abstract

This article is an attempt to develop a coherent, unified, and consistent conceptualization of dreaming and dreamtelling in the clinical setting. Dreams told in a therapeutic setting are challenging events: fantastically rich in content, but often overwhelming in their implications for peoples’ relationships. When told in therapy groups, dreams provide additional challenges for all participants. Learning to work with dreams not only enhances understanding of unconscious intrapsychic and group processes, but may also have a strong impact on the therapeutic culture and working relationships in the group. After differentiating dreaming from dreamtelling, I briefly describe three uses of dreams in groups—the classical “informative” and more familiar “formative” uses, and a new perspective that focuses on the “transformative” aspects of a dream told. According to this perspective, a dream told has an interesting past, an important present, and a worthwhile future because of its interpersonal, intersubjective influence on the dreamer–audience relationship.     

Static and Phasic Cross-Talk Effects in Discrete Bimanual Reversal Movements

The authors examined the hypothesis that the phasic and the static cross-talk effects found in bimanual movements with different target amplitudes originate at different functional levels of motor control, which implies that the effects can be dissociated experimentally. When the difference between the short and the long amplitudes assigned to the 2 hands of 12 participants was decreased, the static effect disappeared. In contrast, the phasic effect, which can be observed only at short preparation intervals, did not disappear; although it became smaller in absolute terms, in relative terms it did not. In addition, the authors compared the time course of amplitude assimilation with the time course of amplitude variability and examined the correlation between left hand and right hand amplitudes. The disappearance of the phasic amplitude assimilation at increasing preparation intervals turned out to be delayed relative to the decline of the correlation between amplitudes. That finding suggests that the assimilation of mean amplitudes and the correlation between left hand and right hand amplitudes are not fully equivalent indicators of intermanual interactions, but may indicate different kinds of inter-limb coupling.     

Intermanual Interactions During Simultaneous Execution and Programming of Finger Movements

In bimanual movements, some differences between the movements performed by the two hands cause interference, while others do not. Similarly, in choice between responses with the left and right hand some differences between the two movements increase RT, while others do not. It is suggested that both kinds of effects are, at least in part, due to the incompatibility between processes that determine characteristics of movements jointly for both hands and that are present during preparation as well as during execution. This hypothesis implies that during execution of one movement, programming of a different movement to be performed with the other hand should be impaired, as compared to a condition in which the successive movements of both hands are the same. This expectation was confirmed for finger movements of different forms where an effect on choice RT had been shown previously. On the other hand, interference between execution and programming is not to be expected when successive movements differ in characteristics that are likely to be specified separately for each hand, as indicated by a lacking effect in choice experiments. This expectation was confirmed for successive movements performed with different fingers of either hand as compared to movements performed with the same fingers.     

Blocking in Rapid Finger Tapping: The Role of Variability in Proximodistal Coordination

In rapid finger tapping, occasional intertap intervals of about twice the normal length or even longer, called blockings, can be observed. Skilled rapid tapping requires that flexor and extensor activity be timed so that they coincide with certain phases of the finger movement. In the present study, the hypothesis examined was that blockings are associated with a deviation from the proper timing relations between the more proximal signals (electromyographic [EMG] bursts) and the more distal signal (position-time curve of the finger). Participants (N = 8) performed up-and-down tapping. Blockings were compared with the preceding normal tapping cycles; a temporal forward shift of the flexor burst in the time interval between two kinematic landmarks—the lifting of the finger and the reversal of the movement—was found consistently in the blockings The phase shift of the flexor burst relative to the kinematic landmarks did not develop gradually in the course of the tapping cycles that preceded the blocking but was an abrupt deviation, which suggests that blockings occur with an increased likelihood as the extremes of the normal variability of the phase relation are approached.