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Author: Fuat Balcı

The dopamine clock hypothesis suggests that the dopamine level determines the speed of the hypothetical internal clock. However, dopaminergic function has also been implicated for motivation and thus the effect of dopaminergic manipulations on timing behavior might also be independently mediated by altered motivational state. Studies that investigated the effect of motivational manipulations on peak responding are reviewed in this paper. The majority of these studies show that a higher reward magnitude leads to a leftward shift, whereas reward devaluation leads to a rightward shift in the initiation of timed anticipatory behavior, typically in the absence of an effect on the timing of response termination. Similar behavioral effects are also present in a number of studies that investigated the effect of dopamine agonists and dopamine-related genetic factors on peak responding. These results can be readily accounted for by independent modulation of decision-thresholds for the initiation and termination of timed responding.

In: Timing & Time Perception
In: Timing & Time Perception
Authors: Tutku Öztel and Fuat Balcı

Our subjective experience of time intervals is susceptible to the effects of the various properties of the timed stimuli/events (e.g., motion, size, affect). For instance, subjective time is considerably lengthened when observing faster and shortened when observing slower walking animations. Such effects on perceived time have been investigated widely in the field. What we do not know based on these studies is if participants are aware of these sorts of stimulus-induced timing illusions. Thus, the current study, using confidence ratings, investigated whether the participants are aware of their largely biased time perception induced by the observed walking speed in a temporal bisection task. After each categorization of a probe interval as ‘short’ or ‘long’, we asked participants to rate their confidence level regarding their categorization. We reasoned that if participants were aware of their biased time perception, the temporal modulation of confidence ratings regarding their categorization performance would not change between different walking speed conditions. We found that confidence ratings closely tracked shifts in the psychometric functions suggesting that participants were not aware of the stimulus-induced warping of perceived time. We replicated these findings in a second experiment. Our results show that human participants are not aware of the stimulus-induced temporal illusions they experience.

In: Timing & Time Perception

Forming temporal expectations plays an instrumental role for the optimization of behavior and allocation of attentional resources. Although the effects of temporal expectations on visual attention are well-established, the question of whether temporal predictions modulate the behavioral outputs of the autonomic nervous system such as the pupillary response remains unanswered. Therefore, this study aimed to obtain an online measure of pupil size while human participants were asked to differentiate between visual targets presented after varying time intervals since trial onset. Specifically, we manipulated temporal predictability in the presentation of target stimuli consisting of letters which appeared after either a short or long delay duration (1.5 vs. 3 s) in the majority of trials (75%) within different test blocks. In the remaining trials (25%), no target stimulus was present to investigate the trajectory of preparatory pupillary response under a low level of temporal uncertainty. The results revealed that the rate of preparatory pupillary response was contingent upon the time of target appearance such that pupils dilated at a higher rate when the targets were expected to appear after a shorter as compared to a longer delay period irrespective of target presence. The finding that pupil size can track temporal regularities and exhibit differential preparatory response between different delay conditions points to the existence of a distributed neural network subserving temporal information processing which is crucial for cognitive functioning and goal-directed behavior.

In: Timing & Time Perception
Editors-in-Chief: Argiro Vatakis, Hedderik van Rijn, and Fuat Balcı
Timing is ever-present in our everyday life – from the ringing sounds of the alarm clock to our ability to walk, dance, remember, and communicate with others. This intimate relationship has lead scientists from different disciplines to investigate time and to explore how individuals perceive, process, and effectively use timing in their daily activities.
Timing & Time Perception aims to be the forum for all psychophysical, neuroimaging, pharmacological, computational, and theoretical advances on the topic of timing and time perception in humans and other animals. We envision a multidisciplinary approach to the topics covered, including the synergy of: Neuroscience and Philosophy for understanding the concept of time, Cognitive Science and Artificial Intelligence for adapting basic research to artificial agents, Psychiatry, Neurology, Behavioral and Computational Sciences for neuro-rehabilitation and modeling of the disordered brain, to name just a few.
Given the ubiquity of interval timing, this journal will host all basic studies, including interdisciplinary and multidisciplinary works on timing and time perception and serve as a forum for discussion and extension of current knowledge on the topic.
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Timing is an integral part of physical activities. Walking as a routine form of physical activity might affect interval timing primarily in two different ways within the pacemaker–accumulator timing-theoretic framework: (1) by increasing the speed of the pacemaker due to its physiological effects; (2) by decreasing attention to time and consequently slowing the rate of temporal integration by serving as a secondary task. In order to elucidate the effect of movement on subjective time, in two different experiments we employed a temporal reproduction task conducted on the treadmill under four different encoding–decoding conditions: (1) encoding and reproducing (decoding) the duration while standing (rest); (2) encoding the duration at rest and reproducing it while moving: (3) both encoding and reproducing the duration while moving; and (4) encoding the duration while moving and reproducing it at rest. In the first experiment, participants were tested either in the 4 or the 8 km/h movement condition, whereas in the second experiment a larger sample was tested only in the 4 km/h movement condition. Data were de-trended to control for long-term performance drifts. In Experiment 1, overall durations encoded at rest and reproduced during motion were under-reproduced whereas durations encoded during motion and reproduced at rest were over-reproduced only in the 8 km/h condition. In Experiment 2, the same results were observed in the 4 km/h condition with a larger sample size. These effects on timing behavior provide support for the clock speed-driven effect of movement and contradicts the predictions of attention-based mediation.

In: Timing & Time Perception
Timing and Time Perception: Procedures, Measures, and Applications is a one-of-a-kind, collective effort to present the most utilized and known methods on timing and time perception. Specifically, it covers methods and analysis on circadian timing, synchrony perception, reaction/response time, time estimation, and alternative methods for clinical/developmental research. The book includes experimental protocols, programming code, and sample results and the content ranges from very introductory to more advanced so as to cover the needs of both junior and senior researchers. We hope that this will be the first step in future efforts to document experimental methods and analysis both in a theoretical and in a practical manner.

Contributors are: Patricia V. Agostino, Rocío Alcalá-Quintana, Fuat Balcı, Karin Bausenhart, Richard Block, Ivana L. Bussi, Carlos S. Caldart, Mariagrazia Capizzi, Xiaoqin Chen, Ángel Correa, Massimiliano Di Luca, Céline Z. Duval, Mark T. Elliott, Dagmar Fraser, David Freestone, Miguel A. García-Pérez, Anne Giersch, Simon Grondin, Nori Jacoby, Florian Klapproth, Franziska Kopp, Maria Kostaki, Laurence Lalanne, Giovanna Mioni, Trevor B. Penney, Patrick E. Poncelet, Patrick Simen, Ryan Stables, Rolf Ulrich, Argiro Vatakis, Dominic Ward, Alan M. Wing, Kieran Yarrow, and Dan Zakay.

Pacemaker-accumulator (PA) systems have been the most popular kind of timing model in the half-century since their introduction by Treisman (). Many alternative timing models have been designed predicated on different assumptions, though the dominant PA model during this period — Gibbon and Church’s Scalar Expectancy Theory (SET) — invokes most of them. As in Treisman, SET’s implementation assumes a fixed-rate clock-pulse generator and encodes durations by storing average pulse counts; unlike Treisman’s model, SET’s decision process invokes Weber’s law of magnitude-comparison to account for timescale-invariant temporal precision in animal behavior. This is one way to deal with the ‘Poisson timing’ issue, in which relative temporal precision increases for longer durations, contrafactually, in a simplified version of Treisman’s model. First, we review the fact that this problem does not afflict Treisman’s model itself due to a key assumption not shared by SET. Second, we develop a contrasting PA model, an extension of Killeen and Fetterman’s Behavioral Theory of Timing that accumulates Poisson pulses up to a fixed criterion level, with pulse rates adapting to time different intervals. Like Treisman’s model, this time-adaptive, opponent Poisson, drift–diffusion model accounts for timescale invariance without first assuming Weber’s law. It also makes new predictions about response times and learning speed and connects interval timing to the popular drift–diffusion model of perceptual decision making. With at least three different routes to timescale invariance, the PA model family can provide a more compelling account of timed behavior than may be generally appreciated.

In: Timing & Time Perception