The role of context on boundary extension

Boundary extension (BE) is a memory error in which observers tend to remember more of a scene than they are actually viewed, which reflects a good prediction of the natural continuation of a scene (Intraub & Richardson, 1989). According to the multisource model of scene perception, scene schema and contextual knowledge are main contributors to support these predictions (Intraub, 2012). In two separate experiments we investigated the necessity of context and scene schema in BE. In Experiment 1, observers viewed scenes that either contained semantically consistent or inconsistent objects as well as objects on white backgrounds. In Experiment 2, observers viewed abstract shapes on blank backgrounds. We also measured individual differences in visual and spatial imagery ability. In all types of scenes and the no background condition there was a BE effect; but critically, semantic inconsistency in scenes reduced the magnitude of BE. When abstract shapes were used instead of meaningful objects, no BE effect was seen. The results also showed that imagery abilities influenced BE ratings only when scenes had no element to trigger prediction. Our findings are consistent with the multisource model. We suggest that although scene schema is necessary to elicit BE, contextual consistency is not required but only increases the magnitude of BE.