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.     

Decision time and movement time in depression: differential effects of practice before and after clinical improvement

Choice reaction time involves, at least two components of response latency, decision time and movement time. Studies of choice reaction time usually provide values of these two components averaged over a given number of trials. The aim of the present study of depressed subjects was to investigate changes across practice on Decision Time (DT) and Movement Time (MT) before and after clinical improvement. 19 depressed subjects were given two sessions of 50 trials each, one before treatment (Di) and one after recovery (Df). Decision time and movement time exhibited quite different patterns. Decision time significantly decreased with clinical improvement. No significant variation across trials was found, in either session. Movement time values varied across trials but the variations observed on Di and Df were significantly different, whereas before treatment latencies recorded at the end of the session were greater than those scored at the start, the contrary was observed after clinical recovery. No significant difference was found between values of movement time scored at the start of the two sessions.     

On the logic of causally necessary and sufficient conditions: Towards a theory of motive-explanations of human actions

Research carried out under the auspices of the Bank of Sweden. Tercentenary Foundation project RJ 86/183: Basic Concepts of Procedural Law in the Light of Present-Day Philosophy of Language and Linguistics.     

HyperCard administration of a block-design task

HyperCard (Atkinson, 1987) is a new development environment for the Macintosh that shows promise for use in psychological research and testing. In this paper, we discuss the development of HyperCard stackware with which a block-design task similar to that of the Wechsler Adult Intelligence Scale-Revised (WAIS-R) can be administered. The reliability and validity of the computerized block-design task was evaluated by administering both the computerized task and the WAIS-R subtest to college undergraduates. Results indicated that the computerized task’s reliability compared favorably with that of the WAIS-R subtest. Validity coefficients were equivocal; although an elapsed-time measure showed moderate correlation between the tasks, the numbers of designs correctly completed in each condition were not significantly correlated.     

Cerebral laterality and depression: differences in perceptual asymmetry among diagnostic subtypes

Examined the influence of diagnostic subtype of depression on perceptual asymmetry for dichotic listening and visual tachistoscopic tasks. A total of 65 unmedicated patients with major depressive disorders and 30 normal controls were tested on a verbal and nonverbal task in each modality. Patients diagnosed according to the DSM-III with melancholia had abnormal perceptual asymmetry for dichotic nonsense syllable and complex tone tasks. In contrast, patients having a nonmelancholic "atypical depression" (reactivity of mood with preserved pleasure capacity and associated features) did not differ from normal controls on these tasks, but had an increased incidence of left handedness. Bipolar depression (history of hypomania) differed from unipolar depression in showing abnormal perceptual asymmetry for a tachistoscopic dot enumeration task. Alterations of perceptual asymmetry in melancholia and bipolar depression were consistent with hypothesized right hemisphere dysfunction.     

Residential density and psychological health: the mediating effects of social support

People report excessive, unwanted social interactions, insufficient privacy, and are observed to be more socially withdrawn under crowded living conditions. If people socially withdraw from one another as a way to cope with crowding, this could lead to an unintended side effect of breakdowns in socially supportive relationships. A breakdown in socially supportive relationships could, in turn, account for some of the pathological consequences of chronic, high density living conditions. An empirical study of 175 male heads of household among inner city residents in India suggests that the adverse effects of residential crowding on psychological health are mediated by a breakdown of social support systems. The study also points to the value of examining social support as an endogenous variable in the stress and health process.     

ASSESSMENT OF STIMULUS PREFERENCE AND REINFORCER VALUE WITH PROFOUNDLY RETARDED INDIVIDUALS

We evaluated a procedure for identifying potential reinforcers with profoundly retarded individuals. In Experiment 1, six persons were repeatedly exposed to 16 stimuli, and approach behaviors to each stimulus were used to identify preferred and nonpreferred stimuli. In Experiment 2, we examined the reinforcing properties of preferred and nonpreferred stimuli by delivering them contingently on the occurrence of arbitrarily selected responses. Results revealed that the preferred stimulus conditions typically produced higher rates of responding than did either the baseline or the nonpreferred stimulus conditions, suggesting that the procedure can be used to assess reinforcer value for individuals with limited behavioral repertoires.