Threshold tracking for assessment of long-term adaptation and sensitization in pain perception

To assess temporal variations in the perception of "phasic" heat pain stimuli a psychophysical tracking procedure was developed that enables repeated assessment of the pain threshold at short intervals. This "double-tracking" procedure produces two tracking curves simultaneously, one that approaches the pain threshold gradually from above, the other from below. The threshold for phasic heat pain was measured in 80 tracking trials with stimuli at temperatures near the pain threshold. Concurrently, the threshold for "tonic" heat pain was determined after every 20 tracking trials with a stimulus adjustment procedure. Eleven healthy subjects (age: 26.4 yr. +/- 6.0) participated in 2 sessions each. Phasic stimulation near the pain threshold did not produce any trends in either of the two threshold measures. Hence there was no long-term adaptation or sensitization. However, there were random variations (random walks) in the tracking curves, which we interpret as resulting from a stochastic relationship between stimulus and sensation. In agreement with other reports, discrimination seemed to be better at painful than at nonpainful temperatures.     

Distributed and massed practice effects on motor performance and learning of autistic children

The purpose of this study was to examine the effect of massed and distributed practice upon the learning by 8 autistic children of rotary pursuit tracking at 20 rpm. The massed practice group of four completed 10 30-sec. trials with 5-sec. rests for 10 consecutive days on the Photoelectric Pursuit Rotor. The distributed practice group completed 10 30-sec. trials with 30-sec. rests for 10 consecutive days on the same device. The results of a 2 x 10 x 10 (group x practice days x trials) analysis of variance with repeated measures on the last two factors indicated that learning occurred for both groups but no differences between groups were significant. It is suggested that further investigations into the applicability of motor learning principles to special populations be conducted using larger groups.     

Acquisition of self-control of a novel muscular activity with EMG and video feedback

To examine the acquisition of voluntary control of a novel muscular activity from the initial stage to the self-control stage, the m. auricularis posterior, which had generally degenerated and had nearly lost its function of drawing an auricle backward in the human body, was selected as a target muscle to be studied. One female undergraduate student who could not move her auricles intentionally was required to activate her left m. auricularis posterior and underwent rest, pretest, training, and posttest sessions once a day for five days. At the subject's request, the electromyograph (EMG) from her left m. auricularis posterior on an oscillograph was provided for her as the feedback signal on each training trial. The picture of her left ear on television was handled in the same way. The EMG measures indicated that the subject could learn to activate her left m. auricularis posterior differentially. The number of training trials on which the subject requested the feedback signals suggested that EMG feedback signal was more useful to her than the video and that the usefulness of the feedback signals varied as the training sessions advanced. It was also concluded from analysis of the self-report data that the acquisition process of self-control of a novel muscular activity could be divided into at least four stages.     

Behavioral sequelae of long-term self-attributed success and failure: an attribution theory analysis

Starting from earlier results that self-caused long-term failure improved performance, this experiment tested the effect of "working conditions" as well as successes and failures succeeding the experience of long-term success and long-term failure. 64 subjects participated in recognition tests, composed of 9 tasks (with 42 stimuli each), to be solved within five different experimental sessions. Subjects received false feedback concerning each judgement. The feedback was designed to correspond to Kelley's informational requirements for self-attributions. Results clearly show an impairment of performances within new "working conditions" if successes succeed long-term failure or long-term success. Failure succeeding long-term failure in new "working conditions", on the other hand, improves performance. Different attribution theories' capacity to explain these results is discussed.     

Objective and simulated stimulation: an empirical study of the effect of indirect suggestion on motor behavior

In an experimental investigation it is demonstrated that motor behavior-in contrast to the opinion forwarded in the literature-is not only elicitable by means of direct persuasion, but also to a great extend by mere indirect suggestion, (feigning of stimuli). A differential investigation of these effects provided evidence that reactions to feigned stimuli are highly person specific and relatively homogenous concerning the respective instruments whereas objective stimuli lead to reactions relatively specific for the respective instrument applied. The findings are interpreted as an analog on to placebo-effects in the area of motor behavior. Their extend may be seen as an argument for a stronger concern with subjective reaction tendencies in this field.     

Acquisition of strategies depending on the opponents' competence level

The development of problem-solving skills from novices to advanced subjects in dependence of the competence level of the opponent is examined in a two-person zero-sum game (Othello). In a repeated-measurement design 18 Ss. (6 Ss in 3 groups) played 10 games against one of three opponent-strategies (implemented on a computer): one "expertlike" strategy, which uses domain specific knowledge and local heuristics (minimax-algorithm with alpha-beta pruning); one "novicelike" strategy, in which global, domain independent problem solving strategies (means-ends analysis, goal-reduction) are implemented; and one strategy, which contradicts the supposed heuristics of the novices, but which results in a "weak" performance (minimization in move-selection). Contrary to our assumptions no significant effects of experience could be verified (win versus loss during single runs). An experience dependent differentiation of global problem solving strategies could not be shown for any of the groups. Neither could a general improving effect of the model for acquiring local, task specific heuristics be proved.     

On the concept of language in some recent theories of meaning

The work on this paper was done in the research project V ra begrepp om spr k supported byHumanistisk-samhälls-vetenskapliga forskningsr det. I am indebted to Per Martin-Löf, Hans Ruin, Pär Segerdahl, and Sven Öhman for valuable comments on a previous version of this paper. Thanks to the comments of the anonymous referee I was able to improve some formulations in the paper.     

Actions, intentions, and consequences: the doctrine of double effect

One interpretation of the doctrine of double effect (DDE) holds that in situations in which good can be secured for some only if others suffer harm, the pursuit of a good tends to be less acceptable when a resulting harm is intended as a means rather than when it is merely foreseen. The doctrine captures certain moral intuitions about pairs of cases which have the same consequential profiles but in which the character of the intention differs. Quinn examines the DDE using three pairs of contrasting cases, two of which are medical examples: the "Direction of Resources" case and the "Guinea Pig" case, both involving allocation of life-saving resources, and the "Craniotomy" case and the "Hysterectomy" case, both involving fetal vs. maternal life. He concludes that the DDE "embodies our sense that certain forms of forced strategic subordination are especially inappropriate among free and equal agents."