Sid d'Entremont¹, Hiu Mei Chow²; ¹St. Thomas University, Fredericton, Canada, ²St. Thomas University, Fredericton, Canada

The tactile Bouba-Kiki (BK) effect refers to a non-arbitrary mental association between tactile sensations (e.g., shape with rounded edges) and other stimuli such as nonsense words (e.g., bouba). It has been reported that individuals with congenital blindness and young children exhibit weaker tactile BK effects. One possible explanation is that these populations may also have weaker visual imagery for abstract shapes, suggesting a link between visual imagery and the tactile BK effect. To test this link directly, we evaluated whether the strength of the tactile BK effect was related to self-reported visual imagery abilities. To measure participants’ visual imagery, we used the Vividness of Visual Imagery Questionnaire (Marks, 1973). Questions involve visualizing familiar images and rating their mental vividness. To measure the strength of the tactile BK effect, we asked participants (n = 30) to perform an audio-tactile task in which they blindly felt some spiky and some round 3D-printed shapes, listened to recordings of nonsense words, and rated the congruence of the word-shape pairs on a 1-7 scale. Results showed that nonsense words containing back vowels (e.g., /a/, /o/, /u/) and bilabial consonants (e.g., /b/, /p/, /m/) were associated with felt round shapes, whereas nonsense words containing voiceless stop consonant (e.g., /t/, /k/) were associated with felt spiky shapes, in alignment with our hypotheses. However, front vowels were not associated with spiky shapes, contrary to typical findings, suggesting that audio-tactile associations might differ from audio-visual ones. Split-half analyses revealed that weaker visualizers (VVIQ < group median, i.e., 57/80) did not exhibit different patterns compared to stronger visualizers (VVIQ ≥ group median), suggesting that voluntary visual imagery might not mediate these associations. A larger sample of weak visualizers (VVIQ < 32/80) may better conclude the involvement of visual imagery in the tactile BK effect.

Acknowledgements: This work was carried out under the Discovery Grant Program of the Natural Sciences and Engineering Research Council of Canada (RGPIN-2024-06028).