Page 114 - It' about time: Studying the Encoding of Duration

duration encoding. Historically, the occurrence of temporal illusions has been a fertile ground for speculations about the mechanisms underlying duration encoding. In particular, duration illusions are often assumed to reflect direct changes in the encoding process (i.e. changing the clock speed), and as such have frequently been used to study the mechanisms underlying the encoding of duration information from sensory information (e.g. Droit-Volet & Wearden, 2002; Eagleman, 2008; Kanai et al., 2006; Pariyadath & Eagleman, 2007; Xuan et al., 2007). The Temporal Frequency Induced Time Dilation (TFITD) illusion used in chapter 4 is a good example of this, since it is assumed to reflect changes in the rate at which temporal information is accumulated during duration encoding (Kanai et al., 2006). In contrast with this assumption, our results suggest that the TFITD illusion does not affect the (channel-based) encoding of duration and likely reflects modulation during subsequent processing. This suggestion is similar to reports demonstrating that the effects of stimulus size and numerosity on duration perception occur during the maintenance of duration information in memory, instead of during duration encoding (Cai & Wang, 2014; Rammsayer & Verner, 2015). While the results reported in chapter 4 only concern a single temporal illusion, our findings do call into question the extent to which duration illusions reflect direct changes in the encoding of duration information. The perception of temporal frequency In chapter 5, we focused on a different topic: the encoding and maintenance of temporal information during occlusion. It is well documented that human observers maintain a representation of the visual features of objects when these objects become occluded. These internal representations allow observers to extrapolate events occurring during occlusion and quickly identify objects 6 upon reappearing. Earlier work has focused mostly on the representation of static properties of objects under occlusion. However, in many situations visual features change as a function of time. Representing these changes, and the rate at which they occur, could provide additional benefits for extrapolation during occlusion and identification of objects upon reappearance. In chapter 5, we investigated whether information about the rate of change of visual information is also represented during occlusion. We used the TFITD illusion in which the perceived duration of an event increases as a function of its temporal frequency content (Kanai et al., 2006). By combining this illusion with General discussion 113