Memory deficits in aphantasics are not restricted to autobiographical memory – Perspectives from the Dual Coding Approach
Monzel, M., Vetterlein, A., & Reuter, M. (2022). Memory deficits in aphantasics are not restricted to autobiographical memory – perspectives from the dual coding approach. Journal of Neuropsychology, 16(2), 444–461. doi:10.1111/jnp.12265
Abstract
Scene Construction Theory suggests similar neural mechanisms for visual imagery and autobiographical memory, supporting the seeming scientific consensus that a loss of visual imagery affects autobiographical memory. Based on the Dual Coding Theory and the Reverse Hierarchy Model, we also assumed influences of visual imagery on recent visual memory and even verbal memory, although little evidence has been provided so far. Thus, in a sample of 67 congenital aphantasics (= persons without mental imagery) and 32 demographically matched controls, it was investigated whether deficits in visual imagery are associated with deficits in visual as well as verbal short‐term and long‐term memory. The memory tasks were theoretically selected based on task difficulty, retrieval condition, and subcategories of stimuli, as previous null findings were attributed to insensitive tasks that were solvable by aphantasics by means of non‐visual alternative strategies. Significant group differences were found in all memory components, with aphantasics performing worse than non‐aphantasics. Therefore, evidence was obtained for the influence of visual imagery on all memory components beyond autobiographical memory.
Overview/Introduction
This study explores how the ability to create mental images, known as visual imagery, affects different types of memory. It focuses on individuals with aphantasia, a condition where people cannot form mental images. The research examines whether a lack of visual imagery impacts both visual and verbal short-term and long-term memory, beyond just autobiographical memory.
Methodology
Participants: The study involved 67 individuals with congenital aphantasia and 32 control participants without the condition.
Assessment Tools: The Vividness of Visual Imagery Questionnaire (VVIQ) was used to measure participants' ability to create visual imagery.
Memory Tasks: Participants completed various tasks designed to test visual and verbal memory, both short-term and long-term. These tasks were carefully selected to ensure they were challenging and required different memory retrieval strategies.
Statistical Analysis: A mixed ANOVA was conducted to compare memory performance between the two groups, considering factors like memory type (visual vs. verbal) and memory duration (short-term vs. long-term).
Key Findings
Performance Differences: Aphantasics performed worse than non-aphantasics across all memory tasks, indicating that visual imagery plays a crucial role in both visual and verbal memory.
No Interaction Effects: The study found no significant interaction between memory type or duration and group membership, suggesting that the memory deficits in aphantasics are consistent across different memory components.
Implications
Understanding Memory Processes: These findings support the Dual Coding Theory, which suggests that memory performance improves when information is processed both visually and verbally. This highlights the importance of visual imagery in enhancing memory.
Educational and Therapeutic Applications: The results could inform strategies for education and therapy, particularly for individuals with aphantasia, by emphasizing alternative memory strategies that do not rely on visual imagery.
Limitations
Task Sensitivity: The study acknowledges that previous research may have used tasks that were not sensitive enough to detect differences in memory performance between aphantasics and non-aphantasics. This study addressed this by selecting more challenging tasks.
Sample Size: While the sample size was sufficient to detect significant differences, larger studies could provide more robust data and further validate these findings.
In conclusion, this research highlights the significant role of visual imagery in memory processes and suggests that individuals with aphantasia may experience broader memory deficits than previously thought. This understanding could lead to improved support and strategies for those affected by aphantasia.