A Temporal Same-Object Advantage for Persisting Objects: Change-Detection Studies of the 'Tunnel Effect'

Meaningful visual experience requires computations that identify objects as the same persisting individuals over time and motion. How does the visual system manage this task for scenes that contain occlusion and featural change? Here we explore this question using a new variant of the ‘tunnel effect’: When an object moves behind an occluder (the ‘tunnel’) and then an object later emerges, we often irresistibly perceive the continuous motion of a single persisting object. This percept occurs even when the pre- and post-occlusion views are featurally distinct, so long as the perceived trajectory is spatiotemporally consistent. Previous studies of the this phenomenon have relied on verbal reports which are notoriously susceptible to higher-level response biases. Here we introduce the first implicit measure of the tunnel effect, involving change detection in dynamic displays. Observers viewed displays in which several objects oscillated behind occluders, each emerging (a) on a spatiotemporally continuous trajectory (‘Tunnel’ events); (b) after a delay (‘Temporal Gap’ events); or (c) in an incongruous location, displaced along the occluder boundary (‘spatial Gap’ events). Objects occasionally changed color while occluded, and observers had to detect these changes. Performance was significantly more accurate for Tunnel events than for either Spatial Gap or Temporal Gap events. We argue that these and related results reflect a new type of dynamic ‘same-object advantage’, in which change detection is improved across temporal scene fragments that are bound into the same persisting object representations. This work also illustrates how spatiotemporal properties play a key role in the perception of persisting objects even in the face of conflicting featural information. We demonstrate how several variants of this task can be used to explore the relative contributions of various cues used by the visual system in the construction of coherent visual experience.