Showing papers on "Time perception published in 1985"

Time perception and attention: The effects of prospective versus retrospective paradigms and task demands on perceived duration

Abstract: This research was designed to compare time judgments obtained under prospective conditions (in which subjects are instructed to attend to time) and retrospective conditions (in which subjects are unaware that they will be required to judge time). In Experiment 1, subjects prospectively or retrospectively judged the duration of intervals spent performing a perceptual-motor task at different levels of difficulty. The results showed that subjects tested under both research paradigms tended to give increasingly shorter and/or more inaccurate time judgments with increases in nontemporal task demands. Experiment 2 was designed to test the effects of attentional deployment on perceived time by comparing prospective and retrospective judgments under control, selective attention, and divided attention conditions. Both types of time judgments became increasingly inaccurate as attention was more broadly deployed. The results of these experiments are consistent with an attentional allocation model, and they suggest that nontemporal task demands disrupt or interfere with timing in both prospective and retrospective situations.

The prefrontal cortex, mediator of cross-temporal contingencies.

Abstract: A large body of empirical evidence supports the notion of a critical role of the prefrontal cortex in the temporal organization of goal-directed behavioral sequences The key element of that role is the bridging of cross-temporal contingencies of behavior, in other words, the adjustment of the actions of the organism to temporally distant events and objectives By the analysis of lesion effects, neuroelectrical phenomena, and metabolic activity we are led to conclude that the prefrontal cortex subserves at least three cognitive functions that allow the mediation of cross-temporal contingencies and, thereby, the formation of temporally extended structures of behavior: short-term memory, preparatory set, and control of interference The three have a somewhat different topographic representation within the prefrontal cortex and thus the principle of its functional heterogeneity is upheld However, all three sustain the supraordinate role of the prefrontal cortex in the temporal integration of behavior

Time Psychophysics and Related Models

Abstract: This paper will deal with the major recent models of time (duration) perception and provide a brief summary of the psychophysical data on which these models are based. Three major issues which pertain to the question of temporal mechanisms will be considered successively: the thresholds for duration, the psychophysical function for time, and the interactions between temporal and nontemporal information.

Interhemispheric relations in patients with chronic alcoholism

Abstract: There have been many investigations of interhemispheric relations during visual perception in normal subjects and these have shown that verbal stimuli are recognized better when presented in the right visual field, whereas nonverbal stimuli are recognized better in the left. To explain the mechanism of lateralization of visual perception many authorities [i5] have emphasized the dominant role of the left hemisphere in the recognition of literal and verbal information and of the right hemisphere in visuospatial analysis of the external environment. However, the perception time of letter stimuli, i.e., the time taken up in analysis and synthesis of information, resulting in its recognition, is much shorter when stimuli are presented in the left visual field, i.e., when they are addressed "directly" to the right hemisphere [6]. The perception time is increased in normal subjects after taking a single small dose of alcohol, and under these circumstances interhemispheric functional relations are altered. The perception time of letters presented in the left visual field is increased and, conversely, it becomes longer than in the case of presentation in the right field. This suggested that the right hemisphere is more sensitive to the action of alcohol than the left. Other investigators also have obtained evidence of disturbance of the functions of the right hemisphere in acute alcohol intoxication [7, 8]. Meanwhile a certain similarity has been noted between the picture of alcoholic intoxication (euphoria, fatuousness, impairment of the critical attitude to their own state) and the psychopathological symptoms of right-sided organic brain lesions [9].

Dynamics of cortical evoked activity during human learning to discriminate microintervals of time using feedback

Abstract: The dynamics of the cortical evoked activity in the process of learning of time microintervals (10, 60 and 180 ms) discrimination was studied in healthy adults. Feedback stimulus visually informing of the real correlations of the differentiated pauses facilitates the discrimination. The factor of the visual field does not affect the estimation of brief time intervals. At correct identifications, the P300 wave is recorded with a higher amplitude, than at errors. In the trial following the "nonconfirming" feedback stimulus, the standard and test stimuli evoke in the left hemisphere a greater P300 wave, than in the trial after the "confirming" stimulus. Feedback influence is retained in the long-term memory.