The shape of a kiki: Sound symbolism affects production of figures

Previous laboratory-based studies of sound symbolism tend to use established sound and meaning distinctions and find strong effects in participants forming mappings between them. Yet sound symbolism in natural language is extant, but only a weak effect. Without constraints and cueing to categorical distinctions in meaning, are sound symbolic effects still observable? We asked 40 participants to draw figures in response to 20 novel words presented auditorially varying in consonant and vowel properties. Plosives and front vowels resulted in more angular and straight-lined figures, whereas sonorants and back vowels elicited more rounded and curved shapes. The results are consistent with the classic bouba-kiki (takete-maluma) effect and show that both consonants and vowels can systematically shape sound-meaning mappings in the absence of explicit constraints. While natural language statistics may partly explain these effects, the consistency across phonemes - including those not frequent in English - suggests deeper perceptual or cognitive origins.