Impact of imagery deficit on word-based object colour retrieval: Evidence from congenital aphantasia

Aphantasia is a form of neurodivergence characterized by an absence of voluntary mental imagery. This absence affects not only basic cognition but also the processing of complex semantic content such as object colour, which typically relies on both visual and verbal representations. According to the Dual Coding Theory (DCT), combining these representations enhances semantic processing. However, this advantage has not been fully investigated under cross-modal conditions. To address this, we tested 24 individuals with congenital aphantasia and 22 controls on object colour decision and retrieval tasks using picture and word stimuli. Unlike controls, individuals with aphantasia showed no benefit from picture-based learning when retrieving colour via words. While their accuracy was unimpaired, their response efficiency was reduced. These findings support DCT and demonstrate the importance of visual imagery in facilitating cross-modal retrieval of object colour under verbal conditions.