Dissociation between activation and attention effects in time estimation: Implications for internal clock models.

Abstract

In a time production task, the participants' activation level and attention devoted to time were manipulated respectively by means of click trains delivered at 2 different intensities during the task and by introducing a concurrent reaction time task. Activation level is classically considered to affect the rate of an internal pacemaker, whereas the way attention affects time estimation is a matter of debate. Three models that differ as to the effect of attention were evaluated. Predictions on the interaction pattern between activation and attention were derived for each of the 3 models. When manipulated jointly, these 2 factors proved to be independent, as they had additive effects on the performance. This finding suggests that the activation level affects the pacemaker rate, whereas the attention level affects an accumulation process by directly acting on a switch functioning in an all-or-none fashion.

Shortening of subjective tone intervals followed by repetitive tone stimuli

“…In agreement with the previous studies (Burle & Bonnet, 1997;Burle & Casini, 2001;Ortega & López, 2008), the psychometric function in Figure 5B shows that the 25-Hz series lasting for 1,000 msec was generally perceived as being longer than the 5-Hz series of the same duration. The intercept of the psychometric function with P .5 shows that the 25-Hz series lasting for 937 msec was equivalent in subjective duration to the 5-Hz series lasting for 1,000 msec.…”

“…Duration of a rapid series of tones (Burle & Bonnet, 1997;Burle & Casini, 2001;Ortega & López, 2008) or duration of a series of flickering visual stimuli (Kanai, Paffen, Hogendoorn, & Verstraten, 2006) themselves are perceived as being longer than that of a static stimulus of the same duration. To explain these changes in time perception, researchers generally hypothesize that some kind of internal pacemaker (Creelman, 1962;Treisman, 1963) is accelerated by the repetitive stimulation.…”

Action, arousal, and subjective time

“…Nonetheless, when arousal has been invoked to explain experimental effects on time perception (e.g. following a train of clicks) effect size increases in a roughly linear manner out to stimulus durations of at least a second (Burle et al, 2001;Wearden et al, 1998). Hence any increase in arousal would have to be maintained for a similar interval.…”

“…Divided attention, for example, typically investigated in a dual-task paradigm (e.g. Burle et al, 2001) now seems an unlikely explanation. Both "attentional gate" and "flickering switch" accounts of attentional effects (Lejeune, 1998;Lejeune, 2000;Zakay, 2000) predict a proportional effect, unless we once again assume that the effect is very brief.…”

“…Various studies have attempted to relate specific effects found in duration discrimination tasks to the function of these clock components (Burle & Casini, 2001;Franssen & Vandierendonck, 2002;Wearden & Culpin, 2002). The broad aim of the experiments described here was to characterise saccadic chronostasis in a similar manner, i.e.…”