Tracking by location and features: Object correspondence across spatiotemporal discontinuities during multiple object tracking

We examined whether surface feature information is utilized to track the locations of multiple objects. In particular, we tested whether surface features and spatiotemporal information are weighted according to their availability and reliability. Accordingly, we hypothesized that surface features should affect location tracking across spatiotemporal discontinuities. Three kinds of spatiotemporal discontinuities were implemented across five experiments: abrupt scene rotations, abrupt zooms, and a reduced presentation frame rate. Objects were briefly colored across the spatiotemporal discontinuity. Distinct coloring that matched spatiotemporal information across the discontinuity improved tracking performance as compared with homogeneous coloring. Swapping distinct colors across the discontinuity impaired performance. Correspondence by color was further demonstrated by more mis-selected distractors appearing in a former target color than distractors appearing in a former distractor color in the swap condition. This was true even when color never supported tracking and when participants were instructed to ignore color. Furthermore, effects of object color on tracking occurred with unreliable spatiotemporal information but not with reliable spatiotemporal information. Our results demonstrate that surface feature information can be utilized to track the locations of multiple objects. This is in contrast to theories stating that objects are tracked based on spatiotemporal information only. We introduce a flexible-weighting tracking account stating that spatiotemporal information and surface features are both utilized by the location tracking mechanism. The two sources of information are weighted according to their availability and reliability. Surface feature effects on tracking are particularly likely when distinct surface feature information is available and spatiotemporal information is unreliable.