The forest, the trees, or both? Hierarchy and interactions between gist and object processing during perception of real-world scenes

Abstract

The global-to-local theories of perception assume that the gist of a scene is computed early and automatically, whereas objects are recognized at later stages and in relation to the gist. To test these theoretical predictions we investigated the time course of gist- and object-recognition, and their interaction in two experiments (total N = 60). Scene images consisting of a background and a foreground object were displayed briefly (between 8 ms and 100 ms) and backward masked. As expected, we found better categorization of backgrounds than objects, and impaired categorization of objects semantically incongruent with backgrounds. But we also observed impaired recognition of backgrounds when an incongruent object was present in the scene, an effect not predicted theoretically. Therefore, we confirm that gist is recognized first and affects subsequent object recognition, but the fact that objects also influence gist processing suggests a bidirectional interaction between both processes.