Remembering Visual Feature Conjunctions: Visual Memory for Shape-Colour Associations is Object-based

Abstract

Visual features can be separately represented in short-term memory so that remembering how they were conjoined to form distinct objects presents additional problems. The involvement of visuo-spatial and verbal representations in memory for visual feature conjunctions is examined in both a review of recent research and a series of five experiments exploring the unitization effect in memory for shape-colour associations. In these experiments, the involvement of verbal representations is controlled in three ways: first, by using shapes varying in nameability; second, by imposing articulatory suppression during encoding of to-be-remembered displays; and, finally, by eliminating all non-visual representational forms through creating sets of shapes based on a single letter of the alphabet. Results concurwiththe conclusions drawn from recentresearch. Verbal representations support memory for shape-colour associations equally well whether the individual features are perceived to belong to the same object or to different objects. In contrast, visual representations support memory for shape-colour associations only when the individual features are perceived to belong to the same object, implying that visual representations are strictly object-based. Object-based visual processing is thus shown to extend beyond selective attention to briefly presented displays and to incorporate the representation in memory of stimuli presented for more extended periods.