Petrizzo, I., Pellegrino, M., Navicelli, I., Anobile, G., Doricchi, F. & Arrighi, R.

Task-dependent interaction between stimulus numerosity and duration.

43rd European Conference on Visual Perception (ECVP) 2021 Online. (2021)


The ATOM Theory suggests that space, time and numerosity might be encoded by a common neural mechanism to pro- mote the interplay between perception and action (Walsh, 2003). In line with that, Xian et al. (2007) demonstrated via a discrimination task that larger or more numerous sti- muli are judged to last longer than smaller/less numerous sti- muli of the same physical duration. However, Yates et al. (2012) reported that the interaction between stimuli dur- ation and size is intrinsically task dependent: the duration of larger stimuli was over-estimated in comparative judg- ments (which stimulus lasts longer?) but the opposite occurred during equality judgments (are the stimuli matched for duration?). Here we investigated whether a task depend- ent interaction also occurs for estimates of the duration of stimuli with different numerosities. Participants judged the duration of a variable test stimulus (duration: 400 -1600 ms; numerosity: 12 or 48; tested in separate sessions) against the duration of a reference (duration: 800 ms; numerosity: 24) in a discrimination and a same/different task. Numerosity strongly affected perceived duration in the dis- crimination task, with more numerous stimuli being per- ceived as lasting longer, but no significant interaction was found for the same/different task. On top of this, duration estimates for stimuli of different numerosity turned out in being rather identical also in a duration reproduction task. Taken together our results suggest that the interactions between magnitudes might not be the automatic outcome of a shared perceptual mechanism, but the result of a percep- tual/cognitive strategy employed in the behavioral task.