Object-based Implicit Learning in Visual Search: Perceptual Segmentation constrains Contextual Cueing

In visual search, detection of a target is faster when it is presented within a layout of nontarget items that is repeatedly encountered, indicating that contextual invariances can guide selective attention (contextual cueing; Chun & Jiang, Cogn. Psychol., 1998). However, perceptual regularities may interfere with contextual learning; for instance, there was no contextual facilitation when four nontarget items formed a global square-shaped grouping, even though the shape was predictive of the target location (Conci & von Mühlenen, Atten. Percept. Psychophys., 2009). Here, we extend our previous findings by showing that contextual cueing can reliably occur for targets located within the region of a globally segmented object, but not for targets presented outside of the object’s boundaries. Four experiments demonstrate an object benefit in contextual cueing, with a modulation of context-based learning by relatively subtle grouping cues including closure, symmetry, and spatial regularity. Moreover, the lack of contextual cueing for targets located outside of the segmented region was due to an absence of (latent) learning of contextual layouts, rather than to attention being biased towards memory-based retrieval of only the item layout in the area defined by the grouped region. Taken together, these results indicate that perceptual segmentation provides a basic structuring within which contextual scene regularities can be acquired. This in turn argues that contextual learning is fundamentally constrained by object-based selection