Κωνσταντίνος Μουτούσης, Επίκουρος Καθηγητής, Ι.Θ.Ε., Εθνικό και Καποδιστριακό Πανεπιστήμιο Αθηνών
Αργυρώ Βατάκη, Επίκουρη Καθηγήτρια, τμήμα Ψυχολογίας, Πάντειο Πανεπιστήμιο
ΕΙρήνη Σκαλιόρα, Εντεταλμένη Ερευνήτρια, Ίδρυμα Ιατροβιολογικών Ερευνών
To inform our sense of the elapsed time, we intergrade temporal cues based on changes of our internal and external world over time. Therefore, dynamic stimuli have long been studied on their effects on duration estimates. However, it is not yet clear which aspect of change is the critical factor that affects perceived time. In our study, we tested three theories that account for how the transformations of a stimulus in a time interval relate to its perceived duration, where the first one emphasizes the role of the absolute number of presented changes, the second one the saliency of the changes, and the third one the neural energy expended to processing its content. We examined, additionally, the significance change’s awareness and the modulatory role of attention on perceived duration of suprasecond intervals. Our experimental method included a dual task in a flickering paradigm with a change detection task and a temporal reproduction task. We used simple visual geometrical stimuli one of which had a positional change, throughout a trial’s duration, which was masked due to the flickering presentation. The timing of perceived change was recorded to examine how attentional distribution affects duration estimates and change’s awareness was assessed in a 4 alternative forced choice task. To independently modulate the neural energy for stimulus processing and the change’s saliency, we manipulated: the number of presented objects (Experiment 1), their presented duration, without changing the interval’s duration (Experiment 2), and the color of the stimuli with a positional change (Experiment 3). Our results did not consistently follow the predictions of any change-related account, although judged duration was affected from the number of perceived changes in about half of our experimental conditions (in Exps. 1 and 2). Change’s detection influenced perceived time only when reached awareness. Attention elicited a minor direct impact on duration judgments and had a weak effect in cases where increased allocation to temporal processing lengthened subjective time according to the Attentional Gate Model. Overall, our findings indicate that in the presence of a salient and predictable flickering stimulus that provides a coherent temporal structure and entrains attention to oscillate, events presented out of this temporality and other, non-temporal, parameters, cannot override the influence of flicker’s frequency on duration estimates.
perceived duration, change perception, phenomenal awareness, attention