Binaural summation after learning psychophysical functions for loudness

Do response-related processes affect perceptual processes? Sometimes they may: Algom and Marks (1990) produced different loudness exponents by manipulating stimulus range, and thereby also modified the rules of loudness summation determined by magnitude scaling. The present study manipulated exponents by having a dozen subjects learn prescribed power functions with exponents of 0.3, 0.6, or 1.2 (re sound pressure). Subjects gave magnitude estimates of the loudness of binaural signals during training, and of monaural and binaural signals after training. During training, subjects’ responses followed the nominal functions reasonably well. Immediately following training, subjects applied the numeric response scales uniformly to binaural and monaural signals alike; the implicit monaural-binaural loudness matches, and thus the basic rules underlying binaural summation, were unaffected by the exponent learned. Comparison of these results with those of Algom and Marks leads us to conclude that changing stimulus range likely influences underlying perceptual events, whereas “calibrating” a loudness scale through pretraining leaves the perceptual processes unaffected.     

An N-channel stroboscopic tachistoscope for typewritten stimuli

The n-channel tachistoscope described employs the principle of “stopping” a continuously moving list of words by means of stroboscopic flashes of light. It can present as many as 50 stimuli per trial at any rate between 5 and 40 items per second. Stimulus materials can be prepared on an electric typewriter. It provides only partial control over the various time parameters.     

Perceived warmth and skin temperature as functions of the duration and level of thermal irradiation!

This study examined the correlations among the degree of perceived warmth. the level and duration of irradiant flux. and the thermal response of the skin. For any constant duration. perceived warmth grew as a power function of the difference between the irradiant flux of the stimulus and the flux that approximates the absolute threshold for warmth. The exponent of the power function was about 0.87 for the shortest durations (2—6 sec). but rose to 1.04 for the longest duration of exposure (12 sec). For any constant level of flux. perceived warmth changed only slightly with duration. In contrast, superficial skin temperature. and inferred temperatures of deeper layers of the skin, rose continuously and markedly with duration. Neither the change in tissue temperature. nor the rate of change of tissue temperature, nor thermal gradient correlated consistently with level of perceived warmth. The change in the difference between the temperature 0.2 mm and that 1.0 mm below the skin surface provided a fairly good but not perfect correlate to perceived warmth. The findings suggest the possibility that sensory adaptation at the site of the receptor system mediating warmth could act in such a way as nearly to offset the effect of rising skin temperature with increased duration ofstimulation.     

Apparent warmth as a function of thermal irradiation

The skin of the back was periodically exposed to a source of radiant heat. In Experiment 1, 20 Ss matched numbers to the apparent warmth aroused by various levels of irradiant flux (method of magnitude estimation). In Experiment 2, 15 Ss matched the loudness of a white noise to the apparent uwmth aroused by the same levels used in Experiment I (method of cross-modality matching). Both experiments showed that apparent warmth is related to absorbed irradiance by a power function whose exponent is approximately 0.7.     

Some new hypotheses on the mediation of loudness judgments 1

A new solution to the problem of relating equal-interval and ratio scales is proposed. It is shown that it is also possible, with the type of theory proposed, to predict results of cross-modality matching experiments.     

Reviews of current books

Pastoral Psychology -     

Legal ethics and the use of mental health experts in criminal cases

The ethical norms of attorneys in mental health law practice are guided by regulatory codes, professional standards, constitutional, evidentiary, and procedural laws, and personal moral values. This article addresses the contours of ethical practice for attorneys in their relationship with mental health experts. In particular, it examines the attorney's responsibility to zealously represent their clients and the ethical limits on such advocacy.