二重符号化理論への挑戦：失顔症における図説優位効果の持続

Dual-coding theory proposes that superior recall for pictures relative to words (the picture superiority effect; PSE) results from encoding information both verbally and visually, creating dual memory codes that aid subsequent retrieval. The current study tested this dual-coding theory by examining recall in individuals with aphantasia, who cannot voluntarily generate mental imagery and thus should not benefit from a secondary visual memory code. We compared recall performance between aphantasics and typical imagers across four stimulus types: pictures, symbols, picture names, and symbol names. Contrary to what dual-coding theory would predict, aphantasic individuals showed a robust picture superiority benefit in memory. While typical imagers recalled pictures and symbols at similar rates, aphantasics recalled symbols significantly better than pictures. These findings challenge dual-coding theory's account of the PSE, revealing that its core assumption-that conscious access to image codes is required for enhanced picture recall-is flawed. Alternative accounts based on distinctiveness are offered, as well as potential substantive revisions that would be required for dual coding to remain a tenable explanation of picture superiority.