Bo-NO-bouba-kiki: picture-word mapping but no spontaneous sound symbolic speech-shape mapping in a language trained bonobo

Humans share the ability to intuitively map ‘sharp’ or ‘round’ pseudowords, such as ‘bouba’ versus ‘kiki’, to abstract edgy versus round shapes, respectively. This effect, known as sound symbolism, appears early in human development. The phylogenetic origin of this phenomenon, however, is unclear: are humans the only species capable of experiencing correspondences between speech sounds and shapes, or could similar effects be observed in other animals? Thus far, evidence from an implicit matching experiment failed to find evidence of this sound symbolic matching in great apes, suggesting its human uniqueness. However, explicit tests of sound symbolism have never been conducted with nonhuman great apes. In the present study, a language-competent bonobo completed a cross-modal matching-to-sample task in which he was asked to match spoken English words to pictures, as well as ‘sharp’ or ‘round’ pseudowords to shapes. Sound symbolic trials were interspersed among English words. The bonobo matched English words to pictures with high accuracy, but did not show any evidence of spontaneous sound symbolic matching. Our results suggest that speech exposure/comprehension alone cannot explain sound symbolism. This lends plausibility to the hypothesis that biological differences between human and nonhuman primates could account for the putative human specificity of this effect

Bo-NO-bouba-kiki : picture-word mapping but no spontaneous sound symbolic speech-shape mapping in a language trained bonobo

This work was supported by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany's Excellence Strategy through EXC 2025/1 ‘Matters of Activity (MoA)’ and by the ‘The Sound of Meaning (SOM)’, Pu 97/22–1 and ‘Phonological Networks (PhoNet)’, Pu 97/25-1. K.M. was supported by the Berlin School of Mind and Brain, by the Onassis foundation, and by the Fyssen foundation. M.A. was supported by the European Research Council under the European Union's Seventh Framework Program (FP7/2007-2013)/ERC grant agreement no. 609819, SOMICS.Humans share the ability to intuitively map ‘sharp’ or ‘round’ pseudowords, such as ‘bouba’ versus ‘kiki’, to abstract edgy versus round shapes, respectively. This effect, known as sound symbolism, appears early in human development. The phylogenetic origin of this phenomenon, however, is unclear: are humans the only species capable of experiencing correspondences between speech sounds and shapes, or could similar effects be observed in other animals? Thus far, evidence from an implicit matching experiment failed to find evidence of this sound symbolic matching in great apes, suggesting its human uniqueness. However, explicit tests of sound symbolism have never been conducted with nonhuman great apes. In the present study, a language-competent bonobo completed a cross-modal matching-to-sample task in which he was asked to match spoken English words to pictures, as well as ‘sharp’ or ‘round’ pseudowords to shapes. Sound symbolic trials were interspersed among English words. The bonobo matched English words to pictures with high accuracy, but did not show any evidence of spontaneous sound symbolic matching. Our results suggest that speech exposure/comprehension alone cannot explain sound symbolism. This lends plausibility to the hypothesis that biological differences between human and nonhuman primates could account for the putative human specificity of this effect.Publisher PDFPeer reviewe

The phylogenetic origin and mechanism of sound symbolism - the role of action-perception circuits

As opposed to the classic Saussurean view on the arbitrary relationship between linguistic form and meaning, non-arbitrariness is a pervasive feature in human language. Sound symbolism—namely, the intrinsic relationship between meaningless speech sounds and visual shapes—is a typical case of non-arbitrariness. A demonstration of sound symbolism is the “maluma-takete” effect, in which immanent links are observed between meaningless ‘round’ or ‘sharp’ speech sounds (e.g., maluma vs. takete) and round or sharp abstract visual shapes, respectively. An extensive amount of empirical work suggests that these mappings are shared by humans and play a distinct role in the emergence and acquisition of language. However, important questions are still pending on the origins and mechanism of sound symbolic processing. Those questions are addressed in the present work. The first part of this dissertation focuses on the validation of sound symbolic effects in a forced choice task, and on the interaction of sound symbolism with two crossmodal mappings shared by humans. To address this question, human subjects were tested with a forced choice task on sound symbolic mappings crossed with two crossmodal audiovisual mappings (pitch-shape and pitch-spatial position). Subjects performed significantly above chance only for the sound symbolic associations but not for the other two mappings. Sound symbolic effects were replicated, while the other two crossmodal mappings involving low-level audiovisual properties, such as pitch and spatial position, did not emerge. The second issue examined in the present dissertation are the phylogenetic origins of sound symbolic associations. Human subjects and a group of touchscreen trained great apes were tested with a forced choice task on sound symbolic mappings. Only humans were able to process and/or infer the links between meaningless speech sounds and abstract shapes. These results reveal, for the first time, the specificity of humans’ sound symbolic ability, which can be related to neurobiological findings on the distinct development and connectivity of the human language network. The last part of the dissertation investigates whether action knowledge and knowledge of the perceptual outputs of our actions can provide a possible explanation of sound symbolic mappings. In a series of experiments, human subjects performed sound symbolic mappings, and mappings of ‘round’ or ‘sharp’ hand actions sounds with the shapes produced by these hand actions. In addition, the auditory and visual stimuli of both conditions were crossed. Subjects significantly detected congruencies for all mappings, and most importantly, a positive correlation was observed in their performances across conditions. Physical acoustic and visual similarities between the audiovisual byproducts of our hand actions with the sound symbolic pseudowords and shapes show that the link between meaningless speech sounds and abstract visual shapes is found in action knowledge. From a neurobiological perspective the link between actions and the audiovisual by-products of our actions is also in accordance with distributed action perception circuits in the human brain. Action-perception circuits, supported by the human neuroanatomical connectivity between auditory, visual, and motor cortices, and under associative learning, emerge and carry the perceptual and motor knowledge of our actions. These findings give a novel explanation for how symbolic communication is linked to our sensorimotor experiences. To sum up, the present dissertation (i) validates the presence of sound symbolic effects in a forced choice task, (ii) shows that sound symbolic ability is specific to humans, and (iii) that action knowledge can provide the mechanistic glue of mapping meaningless speech sounds to abstract shapes. Overall, the present work contributes to a better understanding of the phylogenetic origins and mechanism of sound symbolic ability in humans.Im Gegensatz zur klassischen Saussureschen Ansicht über die willkürliche Beziehung zwischen sprachlicher Form und Bedeutung ist die Nichtwillkürlichkeit ein durchdringendes Merkmal der menschlichen Sprache. Lautsymbolik—nämlich die intrinsische Beziehung zwischen bedeutungslosen Sprachlauten und visuellen Formen—ist ein typischer Fall von Nichtwillkürlichkeit. Ein Beispiel für Klangsymbolik ist der “malumatakete” Effekt, bei dem immanente Verbindungen zwischen bedeutungslosen ‘runden’ oder ‘scharfen’ Sprachlauten (z.B. maluma vs. takete) und runden bzw. scharfen abstrakten visuellen Formen beobachtet werden. Umfangreiche empirische Arbeiten legen nahe, dass diese Zuordnungen von Menschen vorgenommen werden und bei der Entstehung und dem Erwerb von Sprache eine besondere Rolle spielen. Wichtige Fragen zu Ursprung und Mechanismus der Verarbeitung von Lautsymbolen sind jedoch noch offen. Diese Fragen werden in der vorliegenden Arbeit behandelt. Der erste Teil dieser Dissertation konzentriert sich auf die Validierung von klangsymbolischen Effekten in einer Forced-Choice-Auswahlaufgabe (erzwungene Wahl) und auf die Interaktion von Klangsymbolik mit zwei crossmodalen Mappings, die von Menschen vorgenommen werden. Um dieser Frage nachzugehen, wurden menschliche Probanden mit einer Auswahlaufgabe mit zwei Auswahlmöglichkeiten auf klangsymbolische Zuordnungen getestet , die mit zwei crossmodalen audiovisuellen Zuordnungen (Tonhöhenform und Tonhöhen-Raum-Position) gekreuzt wurden. Die Versuchspersonen erbrachten nur bei den klangsymbolischen Assoziationen eine signifikant über dem Zufall liegende Leistung, nicht aber bei den beiden anderen Zuordnungen. Tonsymbolische Effekte wurden repliziert, während die beiden anderen crossmodalen Zuordnungen, die audiovisuelle Eigenschaften auf niedriger Ebene wie Tonhöhe und räumliche Position beinhalteten, nicht auftraten. Das zweite Thema, das in der vorliegenden Dissertation untersucht wird, sind die phylogenetischen Ursprünge der klangsymbolischen Assoziationen. Menschliche Versuchspersonen und eine Gruppe von Menschenaffen, die auf Touchscreens trainiert wurden, wurden mit einer Forced-Choice-Aufgabe auf klangsymbolische Zuordnungen getestet. Nur Menschen waren in der Lage, die Verbindungen zwischen bedeutungslosen Sprachlauten und abstrakten Formen zu verarbeiten und/oder abzuleiten. Diese Ergebnisse zeigen zum ersten Mal die Spezifität der lautsymbolischen Fähigkeit des Menschen, die mit neurobiologischen Erkenntnissen über die ausgeprägte Entwicklung und Konnektivität des menschlichen Sprachnetzwerks in Verbindung gebracht werden kann. Der letzte Teil der Dissertation untersucht darüber hinaus, ob Handlungswissen und das Wissen um die Wahrnehmungsergebnisse unserer Handlungen eine mögliche Erklärung für solide symbolische Mappings liefern können. In einer Reihe von Experimenten führten menschliche Versuchspersonen klangsymbolische Mappings durch sowie Mappings von ‘runden’ oder ‘scharfen’ Handaktionen Klänge mit den durch diese Handaktionen erzeugten Formen. Darüber hinaus wurden die auditiven und visuellen Reize beider Bedingungen gekreuzt. Die Probanden stellten bei allen Zuordnungen signifikant Kongruenzen fest, und, was am wichtigsten war, es wurde eine positive Korrelation ihrer Leistungen unter allen Bedingungen beobachtet. Physikalische akustische und visuelle Ähnlichkeiten zwischen den audiovisuellen Nebenprodukten unserer Handaktionen mit den klangsymbolischen Pseudowörtern und Formen zeigen, dass die Verbindung zwischen bedeutungslosen Sprachlauten und abstrakten visuellen Formen im Handlungswissen zu finden ist. Aus neurobiologischer Sicht stimmt die Verbindung zwischen Handlungen und den audiovisuellen Nebenprodukten unserer Handlungen auch mit den verteilten Handlungs- und Wahrnehmungskreisläufen im menschlichen Gehirn überein. Aktions- Wahrnehmungsnetzwerken, die durch die neuroanatomische Konnektivität zwischen auditorischen, visuellen und motorischen kortikalen Arealen des Menschen unterstützt werden, entstehen und tragen unter assoziativem Lernen das perzeptuelle und motorische Wissen unserer Handlungen. Diese Erkenntnisse geben eine neuartige Erklärung dafür, wie symbolische Kommunikation in unseren sensomotorischen Erfahrungen verknüpft ist. Zusammenfassend lässt sich sagen, dass die vorliegende Dissertation (i) das Vorhandensein von lautsymbolischen Effekten in einer Forced-Choice-Aufgabe validiert, (ii) zeigt, dass lautsymbolische Fähigkeiten spezifisch für Menschen sind, und (iii) dass Handlungswissen den mechanistischen Klebstoff liefern kann, um bedeutungslose Sprachlaute auf abstrakte Formen abzubilden. Insgesamt trägt die vorliegende Arbeit zu einem besseren Verständnis der phylogenetischen Ursprünge und des Mechanismus der lautsymbolischen Fähigkeit des Menschen bei

How arbitrary is language?

It is a long established convention that the relationship between sounds and meanings of words is essentially arbitrary-typically the sound of a word gives no hint of its meaning. However, there are numerous reported instances of systematic sound meaning mappings in language, and this systematicity has been claimed to be important for early language development. In a large-scale corpus analysis of English, we show that sound-meaning mappings are more systematic than would be expected by chance. Furthermore, this systematicity is more pronounced for words involved in the early stages of language acquisition and reduces in later vocabulary development. We propose that the vocabulary is structured to enable systematicity in early language learning to promote language acquisition, while also incorporating arbitrariness for later language in order to facilitate communicative expressivity and efficiency

The functional significance of cross-sensory correspondences in infant-directed speech

Evidence suggesting that infants appreciate a range of cross-sensory correspondences is growing rapidly (see Dolscheid, Hunnius, Casasanto & Majid, 2014; Fernández-Prieto, Navarra & Pons, 2015; Haryu & Kajikawa, 2012; Mondloch & Maurer, 2004; Walker, Bremner, Mason, Spring, Mattock, Slater, & Johnson, 2010; Walker, Bremner, Lunghi, Dolscheid, Barba & Simion, 2018), and yet there is no known attempt to establish the functional significance of these correspondences in infancy. Research shows that speakers manipulate their prosody (i.e. melody of spoken language) to communicate the meaning of unfamiliar words and do so in ways that exploit the cross-sensory correspondences between, for example, pitch and size (Nygaard, Herold & Namy, 2009) and pitch and height (Shintel, Nusbaum & Okrent, 2006). But do infants attend to a speaker’s prosody in this context to interpret the meaning of unfamiliar words? The aim of this thesis is to further establish how infant-directed speakers use prosody to communicate the cross-sensory meanings of words and, for the first time, identify whether infants capitalise on their sensitivity to cross-sensory correspondences to resolve linguistic uncertainty. In Experiment 1 – 4 we identify a list of novel pseudowords to use in all experiments being reported. These pseudowords were judged by participants as being neutral in terms of their sound-symbolic potential, allowing us to rule out the impact of sound-symbolism in our investigation. Experiment 5 provides support for earlier studies revealing cross-sensory correspondences in infant-directed speech. When presented with pseudowords spoken in a prosodically meaningful way, 13-month-old infants demonstrated a preference for objects that were contradictory to the cross-sensory acoustic properties of speech (e.g. lower-pitch voice with higher objects) (Experiment 6), and adults failed to match pseudowords with objects based on the prosodic information that was provided (Experiment 7). However, Experiment 8 provides evidence that 24-month-olds match pseudowords spoken in a higher-pitch voice, and at a faster rate, with objects that are visually higher in space. The implications of these findings are discussed, with suggestions as to how they can be usefully extended

The challenge of olfactory ideophones : Reconsidering ineffability from the Totonac-Tepehua perspective

Olfactory impressions are said to be ineffable, but little systematic exploration has been done to substantiate this. We explored olfactory language in Huehuetla Tepehua—a Totonac-Tepehua language spoken in Hidalgo, Mexico—which has a large inventory of ideophones, words with sound-symbolic properties used to describe perceptuomotor experiences. A multi-method study found Huehuetla Tepehua has 45 olfactory ideophones, illustrating intriguing sound-symbolic alternation patterns. Elaboration in the olfactory domain is not unique to this language; related Totonac-Tepehua languages also have impressive smell lexicons. Comparison across these languages shows olfactory and gustatory terms overlap in interesting ways, mirroring the physiology of smelling and tasting. However, although cognate taste terms are formally similar, olfactory terms are less so. We suggest the relative instability of smell vocabulary in comparison with those of taste likely results from the more varied olfactory experiences caused by the mutability of smells in different environments

The building blocks of sound symbolism

Languages contain thousands of words each and are made up by a seemingly endless collection of sound combinations. Yet a subsection of these show clear signs of corresponding word shapes for the same meanings which is generally known as vocal iconicity and sound symbolism. This dissertation explores the boundaries of sound symbolism in the lexicon from typological, functional and evolutionary perspectives in an attempt to provide a deeper understanding of the role sound symbolism plays in human language. In order to achieve this, the subject in question was triangulated by investigating different methodologies which included lexical data from a large number of language families, experiment participants and robust statistical tests.Study I investigates basic vocabulary items in a large number of language families in order to establish the extent of sound symbolic items in the core of the lexicon, as well as how the sound-meaning associations are mapped and interconnected. This study shows that by expanding the lexical dataset compared to previous studies and completely controlling for genetic bias, a larger number of sound-meaning associations can be established. In addition, by placing focus on the phonetic and semantic features of sounds and meanings, two new types of sounds symbolism could be established, along with 20 semantically and phonetically superordinate concepts which could be linked to the semantic development of the lexicon.Study II explores how sound symbolic associations emerge in arbitrary words through sequential transmission over language users. This study demonstrates that transmission of signals is sufficient for iconic effects to emerge and does not require interactional communication. Furthermore, it also shows that more semantically marked meanings produce stronger effects and that iconicity in the size and shape domains seems to be dictated by similarities between the internal semantic relationships of each oppositional word pair and its respective associated sounds.Studies III and IV use color words to investigate differences and similarities between low-level cross-modal associations and sound symbolism in lexemes. Study III explores the driving factors of cross-modal associations between colors and sounds by experimentally testing implicit preferences between several different acoustic and visual parameters. The most crucial finding was that neither specific hues nor specific vowels produced any notable effects and it is therefore possible that previously reported associations between vowels and colors are actually dependent on underlying visual and acoustic parameters.Study IV investigates sound symbolic associations in words for colors in a large number of language families by correlating acoustically described segments with luminance and saturation values obtained from cross-linguistic color-naming data. In accordance with Study III, this study showed that luminance produced the strongest results and was primarily associated with vowels, while saturation was primarily associated with consonants. This could then be linked to cross-linguistic lexicalization order of color words.To summarize, this dissertation shows the importance of studying the underlying parameters of sound symbolism semantically and phonetically in both language users and cross-linguistic language data. In addition, it also shows the applicability of non-arbitrary sound-meaning associations for gaining a deeper understanding of how linguistic categories have developed evolutionarily and historically

Iconicity emerges and is maintained in spoken language

Iconicity is the property whereby signs (vocal or manual) resemble their referents. Iconic signs are easy to relate to the world, facilitating learning and processing. In this study, we examined whether the benefits of iconicity would lead to its emergence and to maintenance in language. We focused on shape iconicity (the association between rounded objects and round-sounding words like “bouba” and between spiky objects and spiky-sounding words like “kiki”) and motion iconicity (the association between longer words and longer events). In Experiment 1, participants generated novel labels for round versus spiky shapes and long versus short movements (Experiment 1a: text, Experiment 1b: speech). Labels for each kind of stimulus differed in a way that was consistent with previous studies of iconicity. This suggests that iconicity emerges even on a completely unconstrainted task. In Experiment 2 (Experiment 2a: text, Experiment 2b: speech), we simulated language change in the laboratory (as iterated learning) and found that both forms of iconicity were introduced and maintained through generations of language users. Thus, we demonstrate the emergence of iconicity in spoken languages, and we argue that these results reflect a pressure for language systems to be referential, which favors iconic forms in the cultural evolution of language (at least up to a point where it is balanced by other pressures, e.g., discriminability). This can explain why we have iconicity across natural languages and may have implications for debates on language origins. (PsycInfo Database Record (c) 2021 APA, all rights reserved