Abstract
The verbal overshadowing effect refers to the phenomenon that the verbal description of a past complex stimulus impairs its subsequent recognition. Theoretical explanations range from interference between different mental representations to the activation of different processing orientations or a provoked shift in the recognition criterion. In our study, 61 participants with aphantasia (= lack of mental imagery) and 70 controls participated in a verbal overshadowing paradigm. The verbal overshadowing effect did not occur in people with aphantasia, although the effect was replicated in controls. We speculate that this is either due to the lack of visual representations in people with aphantasia that verbal descriptions could interfere with, or to the absence of a shift in processing orientation during verbalisation. To rule out criterion-based explanations, further research is needed to distinguish between discriminability and response bias in people with aphantasia. Finally, data indicated that the verbal overshadowing effect may even be reversed in individuals with aphantasia, partly due to a lower memory performance in the no verbalisation condition. Effects of further variables are discussed, such as mental strategies, memory confidence, and difficulty, quantity and quality of verbalisation.
Overview/Introduction
The verbal overshadowing effect is a fascinating psychological phenomenon where describing something verbally can actually make it harder to recognize that thing later. Imagine trying to describe a suspect's face after witnessing a crime, only to find it more difficult to pick them out of a lineup afterward. This study explores how this effect plays out in people with aphantasia, a condition where individuals lack mental imagery or the ability to visualize things in their mind's eye.
Methodology
Researchers conducted an experiment with 131 participants, 61 of whom had aphantasia and 70 who did not. Participants were shown a video of a bank robber and later asked to identify the robber from a lineup. Some participants described the robber's face before the lineup, while others did not. The study aimed to see if verbal descriptions would affect recognition differently for those with and without aphantasia.
Key Findings
Verbal Overshadowing in Controls: For participants without aphantasia, describing the robber's face before the lineup significantly reduced their ability to recognize the robber, confirming the verbal overshadowing effect.
Aphantasia and Recognition: Interestingly, participants with aphantasia did not experience this effect. In fact, they sometimes performed better when they described the robber's face, suggesting a possible reversal of the verbal overshadowing effect.
Memory Strategies: People with aphantasia relied less on imagination-based strategies and more on feature-based strategies, which might explain why verbal descriptions did not interfere with their recognition ability.
Implications
These findings have important implications, especially in fields like eyewitness testimony. Understanding that people with aphantasia process verbal and visual information differently could lead to more effective interviewing techniques that consider individual differences in mental imagery. This could improve the accuracy of eyewitness identifications and reduce wrongful convictions.
Limitations
While the study sheds light on the interaction between verbal overshadowing and aphantasia, further research is needed to fully understand the mechanisms at play. Specifically, more work is required to distinguish between discriminability (the ability to tell apart different stimuli) and response bias (the tendency to respond in a particular way) in people with aphantasia.
In summary, this research highlights how our minds process verbal and visual information differently based on our mental imagery capabilities, offering new insights into cognitive psychology and practical applications in legal settings.