Beyond Words: Examining the Role of Mental Imagery for the Stroop Effect by Contrasting Aphantasics and Controls

One of the best replicated and most famous effects in experimental psychology, the Stroop effect, describes interferences in cognitive processing when a color word is printed in a conflicting ink color. Recently, the controversial hypothesis was proposed that reading the color word triggers visual imagery, which then interferes with the perceived color, leading to the Stroop effect. Thus, the Stroop effect should not occur in aphantasics, i.e., in individuals with impaired mental imagery. We tested this intriguing hypothesis in a rare sample of 151 aphantasics and 110 controls. Results show that the Stroop effect was reduced in aphantasics, albeit still existing. For the first time, the present data show that an interference between mental imagery and perception is partially responsible for the Stroop effect.