No Verbal Overshadowing in Aphantasia: The Role of Visual Imagery for the Verbal Overshadowing Effect

Abstract

The verbal overshadowing effect refers to the phenomenon that the verbal description of a past complex stimulus impairs the subsequent recognition performance for the same stimulus. Theoretical explanations range from an assumed interference between different mental representations, to the activation of different mental processes, to a provoked shift in the recognition criterion. In our study, 118 participants with aphantasia (= lack of mental imagery) and 119 controls participated in a verbal overshadowing paradigm. The verbal overshadowing effect did not occur in individuals with aphantasia, although the effect was replicated in controls. We propose that this is either due to the lack of visual representations in people with aphantasia with which a verbal description could interfere, or to the absence of a shift in processing orientation during verbalisation. In contrast, a shift in recognition criterion seems unlikely against the background of our results, as people with aphantasia would also be expected to have a more conservative recognition criterion after having difficulties in extensively describing the stimulus in its absence.

Note:
Funding Declaration: None

Conflicts of Interest: None

Ethical Approval: The study was conducted as part of a research project for which no ethics approval was required according to German laws and ethical regulations for psychological research (see section 7.3: https://www.dgps.de/die-dgps/aufgaben-und-ziele/berufsethische-richtlinien/#c53). Informed consent was obtained in accordance with the World Medical Association Declaration of Helsinki (World Medical Association, 2013).

Keywords: recognition memory, verbal overshadowing, eyewitness testimony, aphantasia, visual imagery