Page 101 - It' about time: Studying the Encoding of Duration

Chapter 5 during the period of occlusion. We observed clear time dilation, with longer reproductions for the luminance-modulated stimuli (5 & 10 Hz) compared to the static stimuli. Moreover, this effect was larger for the 10 Hz modulation compared to the 5Hz modulation. Furthermore, time dilation occurred in all three occlusion conditions, with the effect being larger for the Non-Occluded condition compared to the Occlusion and Extinction conditions. More importantly, time dilation was larger in the Occluded condition compared to the Extinction condition. This was true only for the 10 Hz luminance modulation, with no difference being observed for the 5 Hz modulation. This result indicates that the time dilation in the Occluded condition cannot be fully explained by the pre- and post- occlusion presentation of the stimulus. Instead, it argues for a representation of temporal frequency content during periods of occlusion. In a second experiment we manipulated the expected temporal frequency of stimuli during occlusion by presenting occlusion events in different contexts of non-occluded presentations. These contexts consisted of blocked presentations of stimuli that were either static, continuously modulated at 10 Hz, or modulated at 10 Hz with a temporary disruption occurring in line with the occlusion event. The goal of these blocked presentations was to strengthen the assumption that the occluded stimulus had the same visual properties as its non-occluded counterpart. Since the disruption of temporal frequency content occurred during the occlusion of the stimulus, the continuous and disrupted modulations were visually identical when the stimulus became occluded. This allowed us to compare reproductions for occlusion events that were visually identical, but differed in the expected temporal frequency content of the stimulus during occlusion. We observed time dilation for the continuously modulated and disrupted stimuli, both when they were occluded as well as when they remained visible. We also observed larger time dilation for stimuli that were continuously modulated compared to the disrupted stimuli. This was true for the non-occluded presentations, which differed in their visual properties, but also for the occluded presentations, which were visually identical. Because the occluded presentations were visually identical, these observed difference between continuously modulated and disrupted stimuli cannot be explained by pre- and post- occlusion presentations of the stimulus. Together, these results demonstrate that dynamic stimulus properties can be represented during occlusion, and that this representation can be modulated by expectations about the stimulus during the occlusion event. Correlation 100