Increasing word distinctiveness eliminates the picture superiority effect in recognition: Evidence for the physical-distinctiveness account

A well-established phenomenon in the memory literature is the picture superiority effect—the finding that, all else being equal, memory is better for pictures than for words (Paivio & Csapo, 1973). Theorists have attributed pictures’ mnemonic advantage to dual coding (Paivio, 1971), conceptual distinctiveness (Hamilton & Geraci, 2006), and physical distinctiveness (Mintzer & Snodgrass, 1999). Here, we present a novel test of the physical-distinctiveness account of picture superiority: If the greater physical variability of pictures relative to words is responsible for their mnemonic benefit, then increasing the distinctiveness of words and/or reducing the physical variability of pictures should reduce or eliminate the picture superiority effect. In the present experiments we increased word distinctiveness by varying font style, font size, color, and capitalization. Additionally, in Experiment 3 we reduced the distinctiveness of pictures by presenting black-and-white pictures with similar orientations. In Experiment 4, a forced choice procedure was used in which subjects were asked to identify the form that each probe had taken during the study phase. The results were consistent with the distinctiveness prediction and, notably, were inconsistent with dual coding.