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A hand-held tachistoscope for use at the bedside was constructed and used to examine 40 normal controls and 170 psychiatric and neurological patients. This instrument quickly provided an index (perception time) which distinguished between idiopathic psychiatric illness and delirium, and between cortical and subcortical neuropathology. Slow perception time was seen in patients with delirium or cortical neuropathology.
The effects of acute pentobarbital treatment were assessed using a complex operant test battery containing five tasks in which correct performance is thought to depend upon processes associated with short-term memory and attention [delayed-matching-to-sample (DMTS)], color and position discrimination [conditioned position responding (CPR)], motivation [progressive ratio (PR)], time perception [temporal response differentiation (TRD)], and learning [incremental repeated acquisition (IRA)]. Adult, male rhesus monkeys were tested 15 min after IV injection of saline or pentobarbital (1, 3, 5.6, 10, or 15 mg/kg). Behavioral endpoints measured included percent task completed, response rate or latency, and response accuracy. The order of task sensitivity to disruption by PBT was TRD > IRA = DMTS = PR > CPR, in which sensitivity was defined as a significant disruption in any aspect of task performance. PBT slowed response rates at 10.0 and/or 15.0 mg/kg in all tasks. Accuracy was decreased in the TRD task at > or = 5.6 mg/kg but doses of > or = 10.0 mg/kg were required to decrease accuracy in the IRA, DMTS, and CPR tasks. Thus, behavior thought to model time perception (TRD) was more sensitive than behavior modeling learning (IRA), short-term memory and attention (DMTS), and motivation (PR). CPR was the least sensitive behavior. Because pentobarbital exerts its effects at least in part via GABA systems, the effects in the current study were compared with those of a previous study of the acute effects of diazepam. The two compounds exerted fundamentally different effects on operant test battery performance.
Two experiments are described. In Exp. 1, subjects compared the apparent numerosity of two kinds of dot patterns, regular vs irregular, with two different exposures (160 vs 2000 msec.). In Exp. 2, the subjects had to estimate the numerosity of the same patterns, presented one at a time. Analysis showed a relative overestimation of the regular patterns in Exp. 1 but not in Exp. 2. In general an overestimation occurred with an increase in exposure. Such results support our hypothesis of two separate processes as the basis of the two kinds of performance (estimating vs comparison).
Thirty methadone maintenance outpatients were measured 1 and 25 hours after ingestion of methadone on auditory threshold, distance perception, simple and differential reaction time, time perception, attention span, and short-term memory. The results revealed a small but statistically significant difference between the two tests for distance perception. In addition, treatment interacted with preparatory interval on differential reaction time and with sex on attention span.
Research indicates that health beliefs and perceptions are shaped and organized by life experiences. Time perception, also structured by life experiences, can systematically alter individuals' perceptions of disease and evaluations of treatment options. Using the Health Belief Model (HBM), this study examines the effects of ethnicity and hypertension temporal orientation on the health perceptions of 300 African Americans and White Americans with hypertension. Results revealed that African Americans were more present-oriented than White Americans regarding their daily experiences with managing hypertension. Compared to more future-oriented respondents, present-oriented people perceived themselves to be less susceptible to the consequences of hypertension, believed more in the benefits of home remedies and negative aspects of prescribed medication, and believed less in the benefits of prescribed medication and negative aspects of home remedies. We concluded that ethnicity influences hypertension temporal orientation and that hypertension temporal orientation affects perceptions about hypertension and its management. Implications for health and medical care are addressed.
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Monkey performance of operant tasks was used to model several brain functions and monitor the acute effects of MK-801 and phencyclidine (PCP). MK-801 is a relatively selective N-methyl-D-aspartate (NMDA) receptor antagonist, while PCP is an NMDA antagonist that is also active at sigma opiate receptors. A comparison of these drugs' effects may indicate the relative importance of certain neurotransmitter receptor systems for specific behaviors. Learning and time perception behaviors are more sensitive (affected at lower doses) to the disruptive effects of MK-801 than are behaviors that model short-term memory, motivation, and color and position discrimination. Such selective disruption was not obtained for PCP: learning, short-term memory and attention, time perception, and motivation tasks are all equally sensitive to disruption. These findings suggest that specific brain functions are differentially affected by modulation of the NMDA and sigma opiate systems.
Certain empirical evidence suggests that subjects prone to delinquent activity may have faster internal clocks than others. To investigate the relationship between antisocial behavior and time perception and its dependence on the experimental time interval and method and on whether the subject is institutionalized we obtained verbal and production estimates of 5-, 15-, 30-, and 60-sec. intervals from 249 adolescents (156 school attenders and 93 institutionalized subjects) classified into 3 groups according to the intensity of their antisocial activity. Results provide no support for the hypothesis that overestimation of short time intervals is associated with either juvenile delinquency or institutionalization.
Sensory thresholds for vibrations and electrical shocks and the sensory nerve conduction velocity (median nerve) were measured during 30 minutes of induced limb ischaemia in 10 normal subjects and 15 patients with chronic hepatic failure. Sensory action potentials were recorded simultaneously at the wrist and elbow. Seven patients (group A) had a normal perception time for vibrations. As in normal subjects, the potential amplitude decreased from the onset of ischaemia, more pronounced at the elbow than at the wrist, and the conduction velocity became reduced more rapidly in the wrist-elbow than the first digit-wrist segment, indicating impulse propagation with decrement. Eight patients (group B) had a markedly prolonged perception time for vibrations. The reduction of potential amplitude and conduction velocity was considerably delayed, and the impulse propagation showed no evidence of decrement for 20-25 minutes of ischaemia. A rise of the threshold for electrical shocks was absent or very delayed. As in the two other groups, the rise was abrupt and occurred at the moment when the potential below the occluding cuff (elbow) was extinct. In both groups of patients there was an increasing temporal dispersion of action potentials and in patient group A a desynchronization of the late phase of the potential took place early in the course of ischaemia. Differences between groups A and B could not be predicted from the pre-ischaemic nerve conduction data.
By applying multidimensional scaling procedures and other quantitative analyses to perceptual dissimilarity judgments, we compared the perceptual structure of visual line graphs depicting simulated time series data with that of auditory displays (musical graphs) presenting the same data. Highly similar and meaningful perceptual structures were demonstrated for both auditory and visual modalities, showing that important data characteristics (function slope, shape, and level) were perceptually salient in either presentation mode. Auditory graphics may be a highly useful alternative to traditional visual graphics for a variety of data presentation applications.
Study participants performed time perception and production tasks over a set of 4 intervals ranging from 325 to 550 ms. In 3 experiments, variability on both the production and perception tasks was found to be linearly related to the square of the target intervals. If the perception and production of short temporal intervals use a common timing mechanism, the slopes of the functions for the 2 tasks should be identical. The results of Experiment 1 failed to support this prediction. However, when the 2 tasks were made more similar by providing a single (Experiment 2) or multiple (Experiment 3) presentations of the target interval per judgment or production, the perception and production functions were nearly identical. The results suggest that temporal judgments and productions are based on an integrated internal representation of the target interval rather than reference to an internal oscillatory process.
This study sought to uncover information regarding prenatal care services as reported by primiparas. Inadequate prenatal care has been linked with the delivery of low birth weight (LBW) infants and infant mortality. This secondary analysis of a larger study (N = 426) examined the need for and availability, accessibility, and use of prenatal care services by primiparas (n = 141). Results indicated that primiparas delivering LBW infants reported less satisfaction with information on birth control and less information on infant feeding. In addition, mothers of LBW infants reported more often than mothers of normal birthweight infants that transportation and finances were barriers to prenatal care. Childbirth preparation class was the only predictor variable for birth weight in this study.
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Patterning of time is a frequently ignored aspect of human behavior. Individuals handle time durations differently. Responses to time durations were first outlined in the classic work of Hall (in 1959) and include urgency, activity, variety, and whether multiple or isolated tasks are attempted in the same time duration. When patients or other staff vary from the nurse in the way in which time or time perception is handled, difficulty can occur. Understanding the way individuals handle time can assist in dealing with patients and colleagues and is of particular significance in interacting with people from other cultures and races.
The prevalence of episodic macropsia, micropsia, and distortions of time perception was examined by questionnaire in 3,224 high-school students aged 13 to 18 years. About 9% of the students reported having experienced one or more types of episodic illusion within the past 6 months. The prevalence of probable migraine was more than three times higher in students with episodic illusions than in those with no episodic illusions. Experiencing more than one type of illusion was found to be associated with probable migraine. Illusions appeared only during fever or while falling asleep in 25% of a subsample of 1,315 students.
AIMS: To investigate whether heroin addicts demonstrate shortened time horizons and decreased sensitivity to future consequences of their behavior compared to non-drug users. DESIGN SETTING AND PARTICIPANTS: Thirty-four heroin addicts enrolled in a buprenorphine treatment clinic and 59 non-drug-using controls completed a personality questionnaire and two laboratory tasks. MEASUREMENTS: The Stanford Time Perception Inventory (STPI) personality questionnaire assessed orientation to the future, and the Future Time Perspective (FTP) task elicited predictions of the timing and ordering of future events. The Bechara card task measured preferences for decks of cards that range in magnitude and probability of delayed and immediate rewards and punishers. FINDINGS: Heroin addicts scored significantly lower than controls on the STPI scale indicative of future orientation. In the FTP, heroin addicts were less likely to predict events far into the future and less likely to systematically organize events in the future. In the card task, heroin addicts were less likely to win money than controls. They were more likely to play from a deck that contained greater immediate gains but that resulted in large, delayed punishers and overall net losses. They also made fewer selections from a deck that provided an overall net gain via relatively low immediate rewards and frequent small punishments. CONCLUSIONS: Shortened time horizons and decreased sensitivity to delayed consequences may explain drug abusers' persistent use of drugs, despite the long-term negative consequences associated with drug use.
Developmental psychological approaches to the study of time have fallen into 3 categories: studies of time perception; studies of logical, reconstructive abilities; and studies of the understanding of conventional time systems. The present work examines problems spanning the latter 2 categories--the development of children's understanding of temporal cycles and the relationship between cyclic concepts and cognitive development. 62 children, ranging in age from 4 to 10 years, were administered Piagetian tests of classification and seriation and a variety of specially designed cyclic tasks. Results show major progress in the representation of cyclic order and recurrence during the age period examined. For a variety of particular cycles, order responses were shown before continuity responses. The ability to produce a correct order is related to seriation performance but not classification performance when the variance attributable to age is partialed out. Continuity responses appear to be unrelated to performance on either of the Piagetian tasks tested when age is controlled.