Abstract
When an object becomes occluded, many of its visual features (e.g. its colour or form) remain represented by the observer. Here we investigated whether changes in the object’s visual features and the rate at which these changes occur, are also represented during occlusion. We focused on the temporal frequency content of a contrast-modulated stimulus. It has been shown that an increase in a stimulus’ temporal frequency content causes an increase in its perceived duration (Kanai et al., 2006). If this temporal frequency induced time dilation also occurs in situations were the object becomes occluded, it provides evidence that information about temporal frequency content is represented during occlusion. Observers performed an online duration judgement task in which they matched the duration of a contrast modulated test stimulus (static, 4Hz, or 8Hz) to a previously presented (static) standard stimulus (600, 800, 1000, or 1200 ms in duration). During the test phase a black square moved behind or in front of the stimulus, causing it to either remain visible or to become occluded after a short delay. The results show that compared to the 4Hz and static conditions, the duration of the 8Hz condition was perceived to be longer (i.e. time dilation). This temporal frequency induced time dilation occurred both when the object was continuously visible and, more importantly, when it became occluded. Additionally, the amount of time dilation for the different standard durations did not differ between the two visibility conditions. Our findings show that dynamic stimulus properties are maintained in the representation of an object, even when it is temporarily occluded and therefore not visible. Furthermore, this representation affects the timing of the occluded object in a similar fashion as to when the object remains visible.
Meeting abstract presented at VSS 2015