Page 56 - It' about time: Studying the Encoding of Duration

Attention gates the selective encoding of duratione duration after-effect of their model, which can lead to a decrease or increase in perceived duration depending on the state of the switch (Gibbon et al., 1984; Zakay & Block, 1997). This switch is often postulated to be a gating mechanism for duration signals, where changes in attention will change the amount of temporal information that is accumulated during an interval. While these studies provide evidence for a link between attention and perceived duration, they focus on manipulating the extent to which a single, task-relevant stimulus is attended. As such, these studies do not provide insight into the selective encoding of a relevant duration that is embedded in a scene with multiple sources of duration information. Our findings clearly demonstrate that attention does not only change the encoding of a single duration, but also plays a crucial role in selecting which of multiple source of duration information are encoded for further processing. 3 The current study shows that attention allows for the selective encoding of duration information. Given the role of attention in the selective encoding of duration, it is likely that attentional limits dictate the extent to which multiple durations can be effectively selected. In line with this idea, several studies have reported behavioral detriments when processing multiple, temporally overlapping durations (Ayhan, Revina, Bruno, & Johnston, 2012; Cheng et al., 2014; Morgan, Giora, & Solomon, 2008; van Rijn & Taatgen, 2008). Together with the current results, these findings point towards attentional limits in the encoding of duration, suggesting that duration processing is an effortful process with a limited capacity. Interestingly, capacity limits have been suggested to be related to the amount of overlap between the onsets and offsets of stimuli (van Rijn & Taatgen, 2008). This suggests that attention for the entire interval might not be needed and that attending the on- and offset of an interval could be sufficient to encode its duration. It would be interesting to further explore this relation and investigate whether selectively attending the onsets and offsets of stimuli is sufficient to allow for the selective encoding of duration. The extent to which attention can modulate responses to a certain feature have been shown to reflect complexity of the feature and its position in the visual processing hierarchy (Suzuki, 2001). Several studies have shown that the magnitude of attentional modulation of after-effects increases as a function of the complexity of the encoded feature (Alais & Blake, 1999; Festman & Ahissar, 2004; Gibson, 1937; Lankheet & Verstraten, 1995; Rhodes et al., 2011; Spivey & Spirn, 2000; Suzuki, 2001, 2003). Furthermore, neurophysiological studies have demonstrated that attentional modulation of single cells 55