Psychophysiological aspects of time perception (the memory of speed)



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In order to test and measure visual temporal behavior, two rotating disks were built to simulate clocks with variable angular velocities. Thirty-five subjects had to memorize the angular speed of the reference disk (independent variable) and be able to reproduce it later on the adjustable disk (dependent variable) The task of reproduction had to be accomplished under the following conditions: (a) while observing both disks at the same time, (b) 5 sec., 30 sec., 120 sec. later, (c) 5 sec. later but with an adjustable disk half the size of the reference disk, (d) after 120-sec. of physical exercise, (3) after 120 sec. of relaxation, (f) after 120 sec. of arithmetical exercises. Three main hypotheses were stated: (a) The organism makes use of internal physiological clocks, (b) The. organism uses cognitive strategies such as the construction of a "sequential internal model" which is temporally associated with the stimulus, both during the perception phase (learning) and the reproduction phase (Memory, motor program output). (c) The organism stores the speed information directly, through the mediation of the visual system which acts like a tachometer (i.e. without the use of a clock mechanism). The results indicated that: (a) Subjects can memorize angular speeds of 0.88 RPM and 3.16 RPM to at.least within a 13% accuracy, (b) Subjects do not rely on internal physiological clocks, such as heart rate, breathing rate, etc. for perceiving, storing and retrieving angular speed cues. Thus the first hypothesis was rejected, (c) Subjects tend to overestimate the angular speed after relaxation, while they tend to underestimate it after physical or arithmetical exercises, (d) Subjects rely on both inner speech and eye movement to store and retrieve angular speed information from Short-Term-Memory (STM). Thus, both the second and the third-hypotheses were accepted. (e) The rate of inner speech, (i.e. counting of 4 beats by musicians), is increased after relaxation and decreased after physical or mental exercise, even though the subjects are instructed to produce as equal intervals as possible. (f) Continuous counting of 4 beats under any condition, for the purpose of creating equal intervals, produces the next interval to be shorter than the previous interval, (for 3 or 4 consecutive trials), while the 4th or the 5th trial contains longer intervals. This phenomenon is repeated for the first 20 to 25 trials and is independent of any Reaction Time Measurements, (g) Minimum perceptual angular speed measurements did not reveal any significant differences when they were taken under normal, after exercise and after relaxation conditions, (h) The time estimation of an interval produced by a 700 Hz sound stimulus is proportional to the attention span allocated to that stimulus, (i) The experience of the duration of an interval is a function of the "storage size" and the "present level of adaptation."