Abstract
A variety of perceptual and attentional processes contribute to the persistence of object identity during occlusion. Do these processes also constrain our implicit learning of new visual features in unfamiliar contexts, or does statistical learning operate equally well on all available information in a scene? To address this question, we studied statistical learning in ‘bouncing vs. streaming’ displays: two objects moved along the diagonals of a square, passing briefly behind a central occluder at the same moment. Observers can perceive this ambiguous display as either two objects ‘streaming’ past each other on linear trajectories, or as two objects ‘bouncing’ off each other while occluded (each changing direction by 90 deg). We first demonstrated that manipulating the acceleration/deceleration profiles of the objects can reliably determine whether bouncing or streaming is perceived, even when the colors and shapes of the objects change randomly each time they pass behind the occluder. Subjects in the main experiment then viewed such displays in which there were statistically reliable patterns in the transition between different features over time. Subjects viewed 192 such displays (half biased to ‘bouncing’, half to ‘streaming’) with no explicit task during familiarization. In the test phase, they then viewed two pairs and judged which was more familiar. They could readily identify coherent pairs over random pairs [t(35)=10.58, p<.0001]. More importantly, when their choice involved pairs that always appeared together in the same display during familiarization, their selection was biased to those pairs that were consistent with the bouncing or streaming interpretations imposed by the spatiotemporal characteristics of the display [t(35)=2.17, p<.05]. These results suggest that statistical learning of new visual features is constrained by perceptual and/or attentional processes involved in the computation of object persistence during occlusion.
Supported by NIH HD037082, NIH T32 EY07125-13, and NSF 0132444.