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Dissociating voluntary mental imagery and mental simulation: Evidence from aphantasia

DOI: 10.3758/s13421-025-01731-y
Speed, L. J., Geraerds, E. M. E., & McRae, K. (2025). Dissociating voluntary mental imagery and mental simulation: evidence from aphantasia. Memory & Cognition. doi:10.3758/s13421-025-01731-y

Abstract

Intentional visual imagery is a component of numerous aspects of cognition. Related to visual imagery, mental simulation plays a role in language comprehension: modality-specific regions of the brain are activated as an implicit part of people understanding language. The degree of overlap between the processes underlying conscious, voluntary visual imagery versus less conscious, more automatic mental simulation is unclear. We investigated this issue by having aphantasics (people who are unable to experience conscious voluntary visual imagery) and control participants perform a property verification task in which they were asked whether a property is a physical part of an object (e.g., is mane a physical part of a lion?). We manipulated the false trials so that the two words either were associated (semantically related) but did not form an object–part combination (monkey–banana), or were not associated (apple–cloud). Solomon and Barsalou (Memory & Cognition, 32, 244–259, 2004) demonstrated that word association influenced responses when the words in the false trials were not associated, whereas when they were associated, perceptual measures most strongly influenced the results, indicating mental simulation. In the present study, control participants and aphantasics demonstrated similar evidence of the use of both mental simulation and word association when verifying whether the words formed an object–part combination. These results suggest that visual imagery and mental simulation are at least somewhat separable cognitive processes.

Authors

  • Laura J. Speed3
  • Emma M. E. Geraerds1
  • Ken McRae1

Understanding Visual Imagery and Mental Simulation: Insights from Aphantasia

Overview/Introduction

Have you ever tried to imagine a lion's mane or a monkey holding a banana? For most people, these images come to mind easily. However, some individuals, known as aphantasics, cannot voluntarily create such mental images. This study explores the difference between visual imagery—the conscious creation of mental pictures—and mental simulation, an automatic process that helps us understand language by activating specific brain regions. The research aims to determine how these processes overlap and whether they function independently.

Methodology

The study involved two groups: individuals with aphantasia and those with typical visual imagery abilities. Participants were asked to perform a property verification task, where they decided if a property (like a mane) is a part of an object (like a lion). The researchers manipulated false trials to include word pairs that were either semantically related (e.g., monkey–banana) or unrelated (e.g., apple–cloud). This setup allowed the researchers to observe how participants used mental simulation and word association to make decisions.

Key Findings

  • Both aphantasics and control participants used mental simulation and word association to verify object-part combinations.
  • Response times were faster for unassociated word pairs compared to associated ones, suggesting that word association influences decision-making more quickly than mental simulation.
  • There was no significant difference in response times or accuracy between aphantasics and control participants, indicating that aphantasics can engage in mental simulation despite their inability to consciously create visual images.

Implications

These findings suggest that visual imagery and mental simulation are distinct cognitive processes. Even without the ability to voluntarily visualize, aphantasics can still process language effectively through mental simulation. This insight has significant implications for understanding how the brain processes language and imagery, particularly for individuals with aphantasia. It highlights the potential for aphantasics to use other cognitive strategies to compensate for their lack of visual imagery.

Limitations

While the study provides valuable insights, it has some limitations:
  • The sample size was relatively small, which might affect the generalizability of the findings.
  • The study focused primarily on visual imagery, leaving other sensory modalities less explored. Future research could investigate whether aphantasics use other senses, like touch or sound, to compensate for their lack of visual imagery.
In conclusion, this study enhances our understanding of how the brain processes imagery and language, showing that even without conscious visual imagery, individuals can still engage in effective mental simulation. This finding opens up new avenues for exploring cognitiv...