Beyond words: Examining the role of mental imagery for the Stroop effect by contrasting aphantasics and controls
Monzel, M., Rademacher, J., Krempel, R., & Reuter, M. (2025). Beyond words: examining the role of mental imagery for the stroop effect by contrasting aphantasics and controls. Cognition, 259, 106120. doi:10.1016/j.cognition.2025.106120
Abstract
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.
Authors
- Merlin Monzel23
- Janik Rademacher1
- Raquel Krempel3
- Martin Reuter15
Overview/Introduction
The Stroop effect is a well-known phenomenon in psychology where people experience difficulty in naming the color of a word when the word itself is the name of a different color. For example, the word "red" printed in blue ink can cause confusion. A recent hypothesis suggests that this effect occurs because reading the word triggers visual imagery that interferes with perceiving the actual color. This study explores whether individuals with aphantasia, a condition where people cannot form mental images, experience the Stroop effect differently.
Methodology
To test this hypothesis, researchers conducted an experiment with two groups: 151 individuals with aphantasia and 110 control participants without the condition. Participants were asked to complete a series of Stroop tasks, where they had to name the ink color of words that either matched or conflicted with the word's meaning. The researchers measured the speed and accuracy of the participants' responses to determine the presence and extent of the Stroop effect in both groups.
Key Findings
Reduced Stroop Effect in Aphantasics: The study found that while the Stroop effect was still present in individuals with aphantasia, it was significantly reduced compared to the control group.
Interference Between Mental Imagery and Perception: The results suggest that mental imagery does interfere with perception, contributing to the Stroop effect. This interference is less pronounced in aphantasics, indicating that the ability to form mental images plays a role in the phenomenon.
Accuracy and Speed Differences: Aphantasics were slower in responding to incongruent trials but showed higher accuracy compared to controls, suggesting a trade-off between speed and accuracy.
Implications
These findings have several important implications:
Understanding Cognitive Processes: The study provides new insights into how mental imagery affects cognitive processing and perception.
Diagnostic Tools: The results suggest that the Stroop task, often used to assess cognitive inhibition, may need to be reconsidered for individuals with aphantasia or similar conditions.
Broader Applications: Understanding the role of mental imagery in perception could impact various fields, from education to cognitive therapy, by tailoring approaches to individuals' cognitive abilities.
Limitations
While the study offers valuable insights, there are some limitations to consider:
Sample Size and Diversity: The sample size, although rare for aphantasia research, may still limit the generalizability of the findings. More diverse samples could provide a broader understanding.
Complexity of Mental Imagery: The study focuses on involuntary mental imagery, but the complexity of mental imagery and its voluntary aspects could be explored further in future research.
In summary, this research sheds light on the intricate relationship between mental imagery and perception, offering a fresh perspective on the Stroop effect and its underlying mechanisms.