On the Relation Between Time Perception and the Timing of Motor Action: Evidence for a Temporal Oscillator Controlling the Timing of Movement

Studies of time estimation have provided evidence that human time perception is determined by an internal clock containing a temporal oscillator and have also provided estimates of the frequency of this oscillator (Treisman, Faulkner, Naish, & Brogan, 1992; Treisman & Brogan, 1992). These estimates were based on the observation that when the intervals to be estimated are accompanied by auditory clicks that recur at certain critical rates, perturbations in time estimation occur. To test the hypothesis that the mechanisms that underlie the perception of time and those that control the timing of motor performance are similar, analogous experiments were performed on motor timing, with the object of seeing whether evidence for a clock would be obtained and if so whether its properties resemble those of the time perception clock. The prediction was made that perturbations in motor timing would be seen at the same or similar critical auditory click rates. The experiments examined choice reaction time and typing. The results support the hypothesis that a temporal oscillator paces motor performance and that this oscillator is similar to the oscillator underlying time perception. They also provide an estimate of the characteristic frequency of the oscillator.     

Environmental factors in suicide in long-term care facilities.

One major purpose of this study was to identify environmental factors related to suicide in long-term care facilities. Questionnaires were mailed to a random sample of administrators at 1,080 facilities. Information was collected on facility characteristics, overt suicide, and intentional life-threatening behavior. Chi-square analyses revealed 4 environmental characteristics related to suicidal behavior and deaths from suicide: staff turnover, size, auspices, and per diem cost. More suicides occurred in larger facilities and facilities with higher staff turnover. Religious or "other" facilities experienced more suicidal deaths than public or private facilities; facilities charging less experienced more deaths.     

Perception of complex geometric figures in chimpanzees (Pan troglodytes) and humans (Homo sapiens): analyses of visual similarity on the basis of choice reaction time.

In a conditional-discrimination task (matching-to-sample), we assessed similarities among figures consisting of 2 elemental figures through the choice reaction time, nonmetric multidimensional scaling, and hierarchical cluster analysis data from chimpanzees (Pan troglodytes) and humans (Homo sapiens). Humans also rated similarities among figures. The results of the 3 experiments clearly indicated that the reaction time data obtained from chimpanzees' performances were useful measures of the similarities among figures. The results suggested that chimpanzees and humans perceived the complex figures similarly. The outer-contour elements were perceived most dominantly by both species, and the straight-line elements were perceived least dominantly. Both species showed the same perceptual hierarchy or dominance among perceptual categories, as determined by the similarity of simple elements, on the basis of transformational invariances.     

The effect of gender and time-of-day on time perception and mental workload

Two experiments are reported which investigated how subject gender and time-of-day influenced the estimation of duration and the perception of task-related mental workload. In the first experiment, 24 subjects performed a filled time-estimation task in a constant blacked-out, noise-reduced environment at 0800h, 1200h, 1600h, and 2000h, respectively. In the second experiment, 12 different subjects performed an unfilled time estimation task in similar conditions at 0900h, 1400h, and 1900h. At the termination of all experimental sessions, participants completed the NASA Task Load Index workload assessment questionnaire as a measure of perceived mental workload. Results indicated that physiological response, reflected in body temperature change, followed an expected pattern of sequential increase with time-of-day. However, estimates of duration and the perception of mental workload showed no significant effects for time-of-day. In each of the experiments there were significant differences in time estimation and mental workload response contingent on the gender of the participant. These results are interpreted in light of the previous positive findings for circadian fluctuation in performance efficiency and the equivocal findings of a gender difference in time estimation. A unifying account of these collective results is given based on gender by time-of-day interactional effects. An earlier version of this paper was presented at the 32nd Annual Meeting of the Human Factors Society, Anaheim, CA, October, 1988.     

Dimensions of affective experience in three age groups.

The dimensions by which adults of differing ages experience emotion were studied by self-administering questionnaires administered to older adults (n = 828) recruited from Elderhostel programs, middle-aged (ages 30-59) children of Elderhostel attenders (n = 231), and young adult (ages 18-29) subjects recruited from college classes or through Elderhostel participants (n = 207). Elders were higher in emotional control, mood stability, and emotional maturity through moderation and leveling of positive affect and lower in surgency, psychophysiological responsiveness, and sensation seeking. These findings are consistent with the hypothesized increase in self-regulatory capacity with age. These cross-sectional differences cannot, however, be distinguished from cohort-related explanations; they require considerable replication across different types of subjects and further characterization of the dimensions in terms of their functions for self-regulation.