Dingemanse, Mark, Will Schuerman, Eva Reinisch, Sylvia Tufvesson, and Holger Mitterer. 2016. “What Sound Symbolism Can and Cannot Do: Testing the Iconicity of Ideophones from Five Languages.” Language 92 (2): e117–33.
The basic finding is this: people are sensitive to the meaning of ideophones they’ve never heard, even when they are produced by a computer voice and presented without context in a difficult forced choice task. Yet there is also reason for caution: the effect is not nearly as strong as what people have found for pseudowords like bouba and kiki.
As we note in the introduction, “there appears to be a tendency to either underplay or exaggerate the significance of iconicity in the study of language and mind”. In this paper we chart a middle way between these extremes. Here’s a quick summary in 3×3 points:
What we did:
- Sound symbolism (iconicity in spoken language) is usually studied using hand-crafted pseudowords in binary forced choice experiments (think bouba and kiki, as reviewed here), but there are three problems with such experimental designs: (i) they run the risk of inflating effect sizes, (ii) it is unclear how they relate to natural languages, and (iii) they usually don’t control for prosody.
- We designed a study to tackle these problems by (i) adjusting the binary choice task to be more realistic and harder, (ii) using real words and meanings from natural languages, and (iii) teasing apart prosody and segmental features. Essentially, we bring linguistic insights to bear on the psychological study of sound symbolism.
- We take 203 ideophones —lexical sound-symbolic words— from 5 languages and 5 semantic domains and present them to 80 participants in 4 versions: (i) full original recording, (ii) full speech synthesized version, (iii) prosody-only condition and (iv) phonemes-only condition. The versions help us control for variation due to different speakers and help us examine the contributions of prosody and segmental features.
What we found:
- People can choose the correct translation of ideophones at a level significantly above chance (z = 5.82, p < 0.001). So ideophones in Japanese, Korean, Semai, Ewe and Siwu are not fully arbitrary, as is normally assumed of words; they contain iconic cues that even people who don’t speak these languages can pick up.
- Sound ideophones are easiest to guess, but the other semantic domains (movement, texture, color/visual appearance, and shape) come out significantly above chance as well. However, the effect is much more modest than most bouba/kiki studies: in the best versions, people score 57.2% on average (where 50% would be chance level) — quite different from the 95% that has sometimes been claimed for pseudoword studies.
- Performance for the original and resynthesised stimuli is indistinguishable, so our speech synthesis method works. Performance is significantly better for the full versions (i-ii) than for the reduced versions (iii-iv), so both prosody and phonemes contribute to the effect (and neither alone is sufficient).
What we conclude:
- Findings based on pseudowords like bouba/kiki cannot be automatically translated into claims about natural languages (as pointed out here). Ideophones combine iconicity and arbitrariness, and lexical iconicity in ideophones is best characterised as a weak bias, which may be amplified in cultural evolution, and is supported by multimodal performances in actual use.
- Prosody is just as important as segmental information in supporting iconic interpretations (as predicted here). Prior work, which has rarely controlled for prosody, likely overestimates the role of speech sounds and underestimates the role of intonation, duration and other prosodic cues.
- Speech synthesis offers a viable way to achieve experimental control in the study of sound symbolism. To stimulate its wider use we’re making available all stimulus materials, including the diphone synthesis source files we used to create them. Get them at MUSE or OSF.
Sound symbolism is a phenomenon with broad relevance to the study of language and mind, but there has been a disconnect between its investigations in linguistics and psychology. This study tests the sound-symbolic potential of ideophones—words described as iconic—in an experimental task that improves over prior work in terms of ecological validity and experimental control. We presented 203 ideophones from five languages to eighty-two Dutch listeners in a binary-choice task, in four versions: original recording, full diphone resynthesis, segments-only resynthesis, and prosody-only resynthesis. Listeners guessed the meaning of all four versions above chance, confirming the iconicity of ideophones and showing the viability of speech synthesis as a way of controlling for segmental and suprasegmental properties in experimental studies of sound symbolism. The success rate was more modest than prior studies using pseudowords like bouba/kiki, implying that assumptions based on such words cannot simply be transferred to natural languages. Prosody and segments together drive the effect: neither alone is sufficient, showing that segments and prosody work together as cues supporting iconic interpretations. The findings cast doubt on attempts to ascribe iconic meanings to segments alone and support a view of ideophones as words that combine arbitrariness and iconicity. We discuss the implications for theory and methods in the empirical study of sound symbolism and iconicity.