Time perception: effects of sex and sound intensity on scales of subjective duration.

Six women and six men reproduced ten time intervals varying in logarithmic steps between 1.3 and 20 s. The durations were indicated by white noise of 10, 25, 40 and 55 dB SL, different sound intensities in different sessions. It was found that (i) greater sound intensity entails shorter reproductions, and (ii) reproductions by male observers are shorter than those by female, although for both (i) and (ii) there is an interaction with the standard durations. The data were treated in accordance with the "parallel-clock model" (Eisler, 1975), whereby the parameters of the psychophysical power function are determined from duration reproduction data. As in previous experiments (Eisler, 1975), the data showed a break in the function entailing two segments. The effect of sound intensity could be attributed to the exponent, which was lower for stronger noise, and the effect of sex to the weight coefficient of the upper relative to the lower segment of the psychophysical function, the coefficient being lower for men.

A mathematical model for time perception with experimentally obtained subjective time scales for humans and rats.

The concept of sensation measurement with the entailing subjective scales is explained. It is shown that linearity between, e.g. sensation halving values and standard values implies that subjective sensation (output) grows as a power function of the physical measure of the stimulus (input). This outcome can be used in the scaling of subjective duration, based on reproduction experiments, i.e., experiments in which the participants are required to reproduce given time intervals, e.g., indicated by noise. It will be shown that what is reproduction for the participant is halving for the experimenter, making it possible to determine the parameters of the power function. The model is confirmed experimentally for humans and rats, the rats having a lower exponent than adults. In a recent experiment it was shown that the reproduced durations differ between female and male observers as well as for different sound intensities. These differences could be attributed to differences in parameter values. An interesting observation is that almost all power functions exhibit a discontinuity, possibly indicating a switch between different neural loops as the durations become longer.

Subjective time scaling: influence of age, gender, and Type A and Type B behavior.

Forty-eight subjects, divided into 4 equal groups (young and older female, young and older male), reproduced 19 time intervals varying in logarithmic steps between 1.3 and 20 s. The durations were indicated by noise of 50 dB SL. To assess Type A and Type B behavior, the subjects were administered a Swedish version of Jenkins Activity Survey with 21 items. It was found that 1. reproductions of durations by older subjects are longer than those by younger subjects, and 2. reproductions by male subjects are shorter than those by female, although an interaction was also detected between gender and the standard durations. Type A and Type B behavior did not show any main effect. The data were treated in accordance with the "parallel-clock model", whereby the parameters of the psychophysical power function are determined from duration reproduction data. As in previous experiments, the data showed a break in the function, entailing two segments. The effect of both age and gender could be explained by the weight coefficient of the upper relative to the lower segment of the psychophysical function, the coefficient being lower for male and higher for older subjects.