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The ability of humans and animals to perceiving time intervals is analyzed. The fundamental and applied aspects of the problem are considered, in particular, from the standpoint of solving chronopharmacological tasks.
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Cross-language research using synthetic voice-onset-time series over the past 40 years suggests that the Spanish lead contrast is acoustically less salient than the English lag contrast. This study examined monkey identification of a labial consonant-vowel voice-onset-time (CV VOT) series (-60 to +70 ms) in order to obtain a linguistically unbiased estimate of lead versus lag salience. Comparisons were made with both English and Spanish adult human listeners. In a classic two-choice identification test, monkey and Spanish functions were quite variable and showed evidence of sensitivity to three types of voicing cues (lead versus simultaneous versus lag). In contrast, English functions were highly categorical and showed sensitivity to only two types of cues (combined lead/simultaneous versus lag). Next, listeners were explicitly trained via feedback to differentiate stimuli crossing lead and lag boundaries. Here, monkey and Spanish performance was initially more symmetrical than English performance, with the latter showing reduced sensitivity to the lead boundary, but group differences disappeared after extended training. These results provide evidence for perceptual loss in English listeners for aspects of Spanish voicing lead perception.
A time production test was performed in seven normal females and seven females with premenstrual syndrome (PMS). We used a time production test for six time intervals (6, 12, 24, 36, 48, 60 s). Time production tests were performed at 08:00, 14:00 and 20:00 h in the follicular, early luteal and late luteal phases (LLP), respectively. The results are as follows. (1) Normal females showed diurnal variations in time production only in the follicular phase (FP). In this phase, they overproduced time at 08:00 h suggesting that the interval clock in normal females was slowest in the morning. (2) Normal females showed menstrual variations in time production only at 20:00 h. They overproduced time in the LLP suggesting that the interval clock in normal females was slowest in the LLP. (3) Neither diurnal nor menstrual variation was found in PMS subjects at any menstrual stage or at any time of the day. These results suggest that the interval timing system in normal females is under the control of ovarian steroid hormones and the circadian clock, but the control of ovarian steroid hormone or the circadian clock does not operate in PMS subjects.
A pilot study on the time sense of ten depressed patients was performed before and during, as well as after, antidepressant therapy with tricyclic compounds. Short time spans were measured by two methods, giving then two different tasks. Measurements were performed in the morning as well as evening hours, in order to take into account diuranl variations. Accuracy of time estimation was considerably deviant. All except one patient overestimated time. With improvement, time sense also improved. Errors were still greater in the morning. The value of the results are discussed.
The paper is concerned with a model for subjective time estimation as determined by processing effort and number of changes. In a previous paper, a proposal was made that should solve a problem of confounded variables in the area of time estimation. An experimental design was developed to allow for the independent manipulation of processing effort and number of changes. It is shown that this proposal is valid only under the assumption that Stevens' law holds with exponent one. Therefore, another way of conceptualizing this problem is advanced in which one asks for the relative impact of processing effort and change on the parameters of Stevens' law. It can be demonstrated that this law yields considerable fit despite interindividual differences.
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This paper describes the slope transition paradigm (STP), a variant of rapid serial visual presentation (RSVP) that separates early (perceptual) processing time from total response time. The paradigm is based on a very simple idea: provide varying amounts of time for perceptual processing and find the moment when the subject begins to waste time waiting for more data. That moment is a measure of how much time was actually needed. The method was used in two experiments. Results are discussed in relation to set-size effects, perceptual capacity limits, attentional dwell times, and some related neurophysiological findings. The method appears to tap aspects of information processing that differ from those tapped in studies of the psychological refractory period, the attentional blink, and repetition blindness.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
We have studied the distortion of perceived time in a patient with left neglect. This patient consistently over-estimated the duration of stimuli in the neglected space. Overestimation was observed both with an interval comparison (300/700 ms) and with a time production (1 s) paradigm. We suggest that encoding duration in the hundreds of milliseconds range is a process based on an internal clock mechanism. The functioning of that clock varies as a function of the processing load.
Psychopathology, psychometric variables, central arousal and time experience were studied in 30 hyperthyroid female outpatients. While these patients could be significantly discriminated in several of the above-described measures during the acute state of the disease, the intergroup differences disappeared after thyreostatic therapy. The thyroxine level was correlated with elevated beta-activity and the latter with variables of psychopathology and time experience. Hormonal dysbalance in hyperthyroidism is discussed as a biological substrate for neurophysiological changes which in turn causes deterioration in mood and behavior.
Living in isolation from time cues under relatively high and low light intensities for a total (on average) of 24 days, 18 subjects estimated the passage of time by "producing" short (10 to 120 seconds) and long (1h) intervals throughout the experiments. The 1h productions were independent of light intensity and highly positively correlated with the duration of wake times. The short-interval productions were markedly increased under high light intensity. In a subsample of 6 subjects, the interaction between effects of body temperature and light condition on 10-second production was analyzed. Productions were negatively correlated with body temperature. In both dim and bright light, productions decreased by a factor of 0.7 per degree C. In bright light, production was increased by a factor of 1.2 relative to dim light. This effect was not mediated by body temperature, which itself was on average slightly increased in bright light. Since subjective time is slowed by bright light, objective time seems to pass faster in bright light.