Abstract
The bouba–kiki effect depicts a non-arbitrary mapping between specific shapes and non-words: an angular shape is more often named with a sharp sound like 'kiki', while a curved shape is more often matched to a blunter sound like 'bouba'. Previous studies have shown that similar sound-to-shape mappings could happen across different cultures and early in development, suggesting the mappings may be innate and possibly universal. However, it remains unclear what level of processing gives rise to these perceptions. Here we examined whether the congruency of a sound–shape stimulus could be processed prior to consciousness. In Experiment 1, we manipulated the congruency of the stimulus by presenting the non-word 'bubu' or 'kiki' with its correspondent or non-correspondent shape. In each trial, a non-word was combined with a shape and presented with continuous flash suppression. The results exhibited the "congruency effect": Congruent pairs broke suppression and reached conscious awareness faster. Furthermore, we tested whether the congruency effect depended on the sound-shape consistency or was simply a result of the visual similarity between the non-words and shapes. In Experiments 2a and 2b, we trained participants to pair up one of the unfamiliar letters taken from West African Vai Script with the 'bubu' or 'kiki' sound. The congruency of the letter-shape pair was determined by the training received prior to the main experiment. For instance, a letter paired up with the sound "kiki" was deemed to be congruent with the angular shape. Again, the "congruency effect" was obtained. Crucially, Experiments 2a and 2b showed that the congruency effect stemmed from the congruent relationship between the shape and the sound represented by the letter but not the shared visual characteristics. Taken together, our results suggest that sound-shape mapping can happen automatically, and sensory congruency facilitates the access to conscious awareness.
Meeting abstract presented at VSS 2016