There has been a dramatic rise of interest in sound symbolism, systematic associations between sounds and meanings. Despite this, one aspect that is still markedly under-explored is its cumulative nature, i.e., when there are two or more sounds with the same symbolic meaning, whether these effects add up or not. These questions are important to address, since they bear on the general question of how speakers take into account multiple sources of evidence when they make linguistic decisions. Inspired by an accumulating body of research on cumulativity in other linguistic patterns, two experiments on sound symbolism using Pokémon names were conducted with native speakers of English. The experiments tested two types of cumulativity: counting cumulativity, which holds if the effects of multiple instances of the same factor add up, and ganging-up cumulativity, which holds when the effects of different factors add up. The experiments addressed whether these patterns of cumulativity hold in sound symbolism, and, more importantly, if so, how. We found that (1) three factors can show ganging-up cumulativity, (2) counting cumulativity and ganging-up cumulativity can coexist in a single system, (3) ganging-up cumulativity patterns can plausibly be considered to be linear, and (4) counting cumulativity effects can be sub-linear.
Most modern linguistic theories in the twentieth century had been generally assuming that the relationships between sounds and meanings are in principle arbitrary. This thesis of arbitrariness is famously attributed to Saussure (
In recent years, the field has witnessed a rapidly growing body of renewed interest in sound symbolism, which is actively studied from a wide range of perspectives. The rise of interest in sound symbolism is partly evidenced by the fact that there have been so many overview articles written recently on this phenomenon, each with different areas of focus and coverage (
The research on sound symbolism has been flourishing, and these studies have been revealing various intriguing aspects of sound symbolic patterns in natural languages (see the overview papers cited in Section 1.1). However, one issue that has been markedly under-explored is whether sound symbolism shows cumulative patterns or not (
The issue of cumulativity in sound symbolism is important to study since it bears upon the general question of how speakers make a linguistic decision when multiple sources of evidence are available. Broadly speaking, there are two general strategies actively discussed in the decision making literature (
The difference between these two decision-making strategies—or whether cumulativity holds or not—is particularly actively explored in the theoretical phonology literature, since it bears on the question of whether phonological optimization algorithm should be based on rankings (as in Optimality Theory:
It has been conventional to distinguish two types of cumulativity (
As stated above, the issue of cumulativity did not receive much attention in the research on sound symbolism until very recently. For counting cumulativity, there are two impressionistic reports which suggest that sound symbolism may function in a cumulative fashion. One example comes from the ideophone system of the Tsugaru dialect of Japanese, in which two voiced obstruents evoke stronger sound symbolic meanings than one voiced obstruent (
Recent experiments by Kawahara and Kumagai (
There are a handful of previous studies on ganging-up cumulativity in sound symbolism. Thompson and Estes (
The studies reviewed in this subsection seem to suggest that sound symbolic patterns generally show cumulative patterns, supporting the idea that some regression-based mechanism, rather than a fast-and-frugal decision-making mechanism, governs the sound symbolic patterns in natural languages. However, the number and the scope of existing case studies, especially those based on quantitive evidence, are limited, and we believe that this issue of cumulativity in sound symbolism should be explored with more case studies. In addition, while this body of research seems to have established that cumulativity generally holds in sound symbolic patterns, it at the same time has opened up several new questions regarding
1. Specific research questions addressed in the current study
Can more than two factors interact cumulatively?
Can counting cumulativity and ganging-up cumulativity coexist in a single system?
In the case of ganging-up cumulativity, are the results linearly cumulative or sub/super-linearly cumulative?
In the case of counting cumulativity, are the effects linearly cumulative or sub/super-linearly cumulative?
The first question is important to address, partly because of the lack of empirical studies that directly explored this question—to the best of our knowledge, D’Onofrio (
The second question is also under-explored in the context of sound symbolism in particular, and in other domains of linguistic patterns in general. The only studies which addressed this question in the context of sound symbolism are Kawahara, Suzuki, and Kumagai (
The last two questions in 1 delve into the nature of cumulativity in further detail; just because the effects of two factors cumulatively add up, it does not have to be the case that the result is the linear sum of the contributions of the two factors. Instead, cumulativity can manifest itself as a sub-linear or super-linear pattern. A schematic, simplified way to think about this question is that if 1 + 1 = 2 holds, that is a case of linear cumulativity. It is conceivable, however, that 1 + 1 could result in 2.5, which is a case of super-linear cumulativity, or that 1 + 1 could result in 1.7, which would be a case of sub-linear cumulativity. Recent studies which tested cumulativity effects in phonotactic learning experiments show that non-linear cumulative patterns are indeed possible (
The main purpose of the current paper is to address the nature of cumulativity in sound symbolic patterns in natural languages; however, the current studies can also be understood as case studies of Pokémonastics, a research paradigm in which researchers explore the nature of sound symbolism in human languages using Pokémon names (
One advantage of Pokémonastics is the fact that, as of 2020, there are more than 800 Pokémon characters, which allows for quantitive analyses of sound symbolism using real, albeit made-up, names. This
Additionally, Pokémon characters are specified for various attributes, such as weight, height, strengths, evolution levels, and types. This nature of the Pokémon characters allows researchers to address the general question of which semantic concept can be symbolically expressed in natural languages (e.g.,
Another advantage is the fact that the set of denotations that are assigned a name is fixed across all languages in the Pokémon universe. In this respect, the Pokémonastics project has important precedents, i.e., Berlin (
For example, when concepts were found to have multiple forms (e.g., gender inflections), only the unmarked form was selected to ensure comparability across languages, as long as relevant information about the meaning was provided through the lexical entries or grammatical descriptions, i.e., in the singular nominative for accusative systems, in the singular absolutive for ergative systems, and so forth. In many languages, the same concept can have a number of different roots or versions…which makes it difficult to know which form of a group of words is the unmarked one. Likewise, throughout languages, most concepts also have several synonyms. Therefore, all phonemes from all forms in these cases were combined into a single string rather than selecting only one of the forms to represent the concept in question. For example, the three English forms of the third person singular personal pronoun (
We do not wish to imply that this complication is insurmountable, as the quote above shows, but it does present an additional layer of analytical complexity, possibly increasing researcher degrees of freedom (
In short, the Pokémon universe makes it possible to conduct a quantitative study of sound symbolic patterns in an ecologically realistic setting. In this spirit, Shih et al. (
In Pokémonastics, it is also possible to conduct experiments to explore which Pokémon properties are symbolically expressed how in what languages. For example, how evolution levels are symbolically expressed have been explored in Japanese (
The pair of pictures used to illustrate pre-evolution versus post-evolution Pokémon characters, drawn by a digital artist
The majority of the experimental Pokémonastics studies, however, is still limited to those targeting Japanese speakers. In order for the Pokémonastic paradigm to provide a useful resource for cross-linguistic studies of sound symbolism in general, more studies targeting languages other than Japanese are hoped for. In addition to the issue of cumulativity in sound symbolism, this is another gap in the Pokémonastics literature that the current experiments are intended to address.
In order to address the theoretical and empirical issues outlined above, the experiment manipulated three linguistic factors: (i) vowel quality ([a] versus [i]), (ii) voicing of obstruents (voiced versus voiceless), and (iii) name length (short versus long). The main purpose of the experiment was to examine whether these three factors interact cumulatively or not. This design also allows us to address another question regarding the nature of cumulativity—whether the cumulative effects are linear or sub/super-linear (
In addition to addressing the nature of cumulativity in sound symbolism, each of the sound symbolic associations that is tested in the experiment has a plausible phonetic or psycholinguistic basis (
The first factor, the vowel quality difference ([a] versus [i]), instantiates a well-known sound symbolic effect, in which the vowel [a] is associated with large images, whereas the vowel [i] is associated with small images (e.g.,
These sound symbolic associations ([a]=big, [i]=small) have been shown to hold for English speakers in previous experiments on sound symbolism (
The second factor that is manipulated in the experiment is the effects of obstruent voicing. Newman (
Shih et al. (
The third factor, phonological length, was first identified as an active sound symbolic principle in the existing set of Japanese Pokémon names (
To recap, building upon the previous studies on Pokémonastics, which themselves are inspired by the general studies of sound symbolism, the current experiment manipulated three phonological dimensions (vowel quality, obstruent voicing, and name length) to examine whether each of these factors impacts the judgment of evolvedness in Pokémon names. More importantly, to the extent that these factors impact the judgment of evolvedness, an ensuing question was whether they do so cumulatively, and if so, how.
Experiment 1 had three factors which were fully crossed; six items were included in each cell. The full list of the stimuli is given in Table
The list of stimuli for Experiment 1.
Voiceless | |||
---|---|---|---|
[i] short | [i] long | [a] short | [a] long |
pinkin | prinklin | pankan | pranklan |
pintil | prinslim | pantal | pranslam |
tinsin | trinslin | tansan | translan |
timpim | trimplim | tampam | tramplam |
kimpin | krimplin | kampan | kramplan |
kintil | krinslin | kantal | kranslan |
bingin | bringlin | bangan | branglan |
bindil | brinzlim | bandal | branslam |
dinzin | drinzlin | danzan | dranzlan |
dimbim | drimblim | dambam | dramblam |
gimbin | grimblin | gamban | gramblan |
gindil | grinzlin | gandal | granzlan |
The experiment was distributed online via SurveyMonkey. The responses were collected using the ‘buy response’ function of SurveyMonkey. A total of 150 participants, who passed all the inclusion criteria (see Section 2.2.3), completed the experiment.
The first page of the experiment was a consent form, which was approved by the first author’s institute. The second page presented the qualification questions, and only those who fulfilled all four of the following conditions were allowed to proceed: (1) they were a native speaker of English, (2) they were familiar with Pokémon, (3) they were not already familiar with sound symbolism, and (4) they had not participated in a Pokémonastics experiment before.
In the instructions, the participants were told that the experiment is about how they would name new Pokémon characters. They were also told that there are two aspects of Pokémon that are crucial: (1) Pokémon characters undergo evolution, and when they do, they are called by a different name, (2) when Pokémon characters undergo evolution, they generally become larger, heavier, and stronger. The participants were provided with an example pair that illustrates the difference between pre-evoluation character and post-evolution character using a pair of non-existing Pokémon characters, shown in Figure
Within each trial, the participants were given one nonce name and asked to judge whether that name is better for a pre-evolution character or a post-evolution character, i.e., the task was to make a binary decision. The stimuli were presented in the English orthography, although they are asked to read each stimulus in their head before making their responses.
The results for this experiment, as well as those for Experiment 2 below, were analyzed using hierarchical Bayesian mixed effects logistic regression using the
Bayesian models yield a distribution of possible values for each parameter of interest, which can be interpreted by examining the middle 95% of these values, called the 95% Credible Interval (abbreviated as ‘95% CI,’ followed by bracketed upper and lower bounds). We can interpret these values directly as our degree of belief in the estimate of the role of the factor in explaining the data (see e.g.,
Taking a Bayesian approach has two advantages in the current context. First, this method generally allows us to fit the complex model with multiple interaction terms justified by the experimental design without convergence issues. The second advantage is that the Bayesian approach allows us to directly access how meaningful the interaction terms are in the explanation of the data, rather than merely telling us whether we can reject a null hypothesis or not, as in frequentist (that is, non-Bayesian) analyses. These two advantages are important because linearity of cumulative interaction can be examined in light of how meaningful the interaction terms in question are.
The results are graphically represented in Figure
The results of Experiment 1. Each dot represents the ‘evolved response’ for each item, averaged over all the participants.
The results of the hierarchical Bayesian logistic mixed effects model show that name length (long versus short,
The current results first of all show that three phonological factors can independently impact the judgment of evolvedness in naming new Pokémon characters. Further, the fact that each factor exerts its own effect regardless of the presence of other factors is evidence that cumulativity of three factors is possible in judgment concerning sound symbolism. In other words, the results instantiate a clear case of ganging-up cumulativity of three factors. We submit that this is an interesting, if not entirely novel, result—recall that D’Onofrio (
The current results show that there is no strong evidence that the interaction terms play a clearly substantial role in predicting the participants’ judgments for the case at hand. In other words, it appears that when two or three factors are relevant, the probabilities of the outcomes can plausibly be predicted based on the summed contribution (in log-odds) of each factor at play. For the case at hand, then, the cumulative effects appear to be linear (although see the R markdown file for complete details).
Finally, as discussed in section 2.1, the sound symbolic effects of vowels and voiced obstruents on evolution levels are not observed in the existing English Pokémon lexicon (
In order to further our understanding of the nature of cumulativity in sound symbolic patterns, Experiment 2 tested counting cumulativity by varying name lengths in three degrees (short versus medium versus long). To test whether counting cumulativity and ganging-up cumulativity can co-exist, this factor was crossed with the binary vowel quality difference tested in Experiment 1.
The experimental procedures were almost identical to those of Experiment 1, so we only highlight the important differences.
The list of the stimuli in Experiment 2 is shown in Table
The list of stimuli for Experiment 2.
[i] short | [i] medium | [i] long |
---|---|---|
pini | pinkin | prinklin |
pimi | pimpil | primplim |
pili | piltim | prilslim |
tini | tinsin | trinkrin |
timi | timpim | trimplim |
tili | tilpil | trilspil |
kimi | kimpin | krimplin |
kini | kintil | krinslin |
kili | kiltim | kriltrim |
pana | pankan | pranklan |
pama | pampal | pramplam |
pala | paltam | pralslam |
tana | tansan | trankran |
tama | tampam | tramplam |
tala | talpal | tralspal |
kama | kampan | kramplan |
kana | kantal | kranslan |
kala | kaltam | kraltram |
A total of 147 native speakers of English participated in this experiment. They were recruited online from two universities in the United States (University of Toledo and UCLA), as well as from the ‘Psychological research on the net’ website.
Taking the theoretical quantity of length as a continuous scale, we coded the length factor numerically as 1, 2, and 3. Other aspects of the analysis were identical to those of Experiment 1, although we report an additional analysis to examine the question of whether the counting cumulativity pattern is linear or sub/super-linear in Section 3.2.2.
Figure
The results of Experiment 2, showing the cumulative effect of name length modulated by the vowel quality difference. Each dot represents average ‘evolved response’ for each item.
The mixed-effects Bayesian modeling analysis shows that the binary variable of vowel ([a] versus [i],
To assess whether the counting cumulativity was linear or not, we re-fit the model above with length as a three-level unordered factor. We then used the posterior samples returned by the Bayesian model to calculate the distributions of probable values of the log-odds of being judged evolved for each combination of length and vowel quality. The results are plotted in Figure
Estimates of the log-odds of being judged evolved for each level of length, divided by vowel quality.
Since we are interested in whether the change in log-odds when moving from short to medium is different from that of moving from medium to long, we subtracted the adjacent categories from each other, yielding distributions over differences in Figure
Differences in effect of length by category, divided by vowel quality.
Finally, we can use these distributions to answer the question of whether counting cumulativity is linear, sub-linear, or super-linear. Linear cumulativity means that the log-odds of being judged evolved increases by the same amount for each adjacent pair of levels; if this were the case in Experiment 2, we expect the pink and blue distributions to be entirely overlapping; to the degree that they are not, the cumulativity is sub-linear (pink below blue) or super-linear (blue below pink).
To more directly visualize the linearity of counting cumulativity, we can simply examine whether the difference between these two distributions is positive, negative, or centered on zero. Further, we can average across the two vowel qualities, since our hypothesis in (1d) above does not concern whether the linearity of counting cumulativity itself differs by what it is ganged with; such a question is interesting, but beyond the scope of conclusions that can be reasonably drawn using this experiment.
Differences in effect of length by category.
Experiment 2 demonstrated that counting and ganging-up cumulativity simultaneously obtain in the domain of sound symbolism (
Going beyond the question of whether cumulativity holds in sound symbolism or not, we found that ganging-up cumulativity (the interaction between the length factor and the vowel factor) seems to be linearly cumulative, while there is strong evidence that counting cumulativity (the gradual increase along the continuous length dimension) is sub-linear. Where this difference comes from is an interesting question, but it is beyond the scope of this paper to provide an answer. Nevertheless, the current results open an opportunity for future investigation on cumulativity in sound symbolism and other linguistic patterns to address how cumulativity manifests itself in which contexts (
The two experiments reported in this paper have shown that sound symbolic effects operate cumulatively when English speakers are provided with new names for Pokémon characters and are asked to judge their evolution status. One may ask if the observed cumulative patterns are surprising at all; i.e., they could have been otherwise. Our answer is positive. Going back to the general issue of how speakers make linguistic decisions (Section 1.2), the participants could have resorted to a fast-and-frugal decision-making strategy (
As discussed in Section 1.2, the issue of how cumulativity works in sound symbolism has been relatively understudied (
To expand on this last point, while our results demonstrated that the sound symbolic pattern in Pokémon names shows cumulative properties, the current results do not necessarily entail that all sound symbolic patterns have to operate this way. There are several issues that can and should be addressed building on what we already know—and what we have now learned—about how cumulativity works in sound symbolism. For example, the semantic notion that was studied in the current experiments is evolvedness, which is closely related to the gradable, scalar notion of size, weight, and strengths. The previous studies which addressed cumulativity in sound symbolism (reviewed in Section 1.2) also tend to target gradable and scalar notions such as size (
Since the issue of cumulativity in sound symbolism is generally understudied, we are unable to offer a full-fledged answer to this question in this paper. The only study that we know of which may bear on this question is Kawahara et al. (
A related question is whether the difference between social versus referential meanings can matter with respect to whether, and how, cumulativity holds in sound symbolic patterns. The same question can be asked with respect to the difference between propositional meanings and attitudinal meanings. These questions too are interesting ones, although they can only be answered with different sets of quantitative studies. While the range of semantic dimensions that can be studied in Pokémonastics is fairly wide (size, weight, strengths, type, etc.), we obviously need to go beyond Pokémonastics to address all of these questions.
While cumulativity seems to be the norm in sound symbolism, as the studies reviewed in Section 1.2 as well as the current results show, there may also be cases in which one segment has such a strong sound symbolic meaning that one occurrence deterministically conveys that meaning, in which cases cumulativity is unexpected. Palatalization found in Japanese baby-talk, which symbolically expresses ‘childishness’ may instantiate such an example, where one instance of palatalization makes the whole utterances undoubtedly ‘child-like’ (
All in all, we hope that our paper stimulates more research on this question—how cumulativity manifests itself for what kinds of semantic meanings in what contexts—not only in sound symbolism but also in other domains of our speech behavior.
In addition to addressing the nature of cumulativity in sound symbolism, the current experiments have contributed toward expanding available data on Pokémonastics, a resource that can be used for cross-linguistic comparisons of sound symbolic patterns (
The fact that we found an effect of voiced obstruents in Experiment 1 is also encouraging, as in one of the previous studies, the effect was not significant (
This hypothesis is further supported by our results which showed clear effects of name length, identified both in Experiments 1 and 2. The iconicity of quantity is a well-known sound symbolic principle (
We would like to emphasize at this point that our investigation of the (non-)linearity of cumulativity in sound symbolism is inspired by several studies on this topic conducted in the formal phonology community (
Recall that the exploration of cumulative nature of linguistic patterns is an actively debated topic in the theoretical phonology literature, because it bears on the question of choosing between Optimality Theory (
As briefly touched upon in Section 1.2, and more extensively reviewed in Breiss (
The current results lend further support to the general hypothesis that phonological patterns and sound-symbolic patterns share non-trivial properties, and hence can and should be studied in tandem with each other. Recall that Experiment 2 revealed a sub-linear cumulativity pattern, and a recent study showed that such a non-linear pattern is also possible in phonotactic judgment patterns (
To summarize, we believe that formal phonology can inform research on sound symbolism. We further hope that the relationship can be a mutually beneficial one. To the extent that there are non-trivial parallels between sound symbolic patterns and other phonological patterns, we may be able to study sound symbolic patterns to explore the general nature of linguistic patterns as well (
The experimental data from the current experiments as well as the R markdown files are available as supplementary materials at
Although these two writers are often cited as the influential figures who had established the arbitrariness thesis at the center of modern linguistic theories, there are many precedents who have made similar statements, including Locke (
Nielsen and Dingemanse (
The sound symbolic connection between sonorants and femaleness holds in languages other than Japanese. See Sidhu and Pexman (
Although Thompson and Estes (
We hasten to add that studies of sound symbolism using real words, such as basic vocabularies, are no less important than the Pokémonastics studies, as they have been revealing important aspects of sound symbolism (
Other potential benefits of the Pokémonastics approach, not discussed in further depth in this paper, include their potential application to teaching and public outreach (
This sound symbolic principle may arguably be grounded in the domain-general iconic mapping between the length of a vector in one modality to the size of a vector in another modality (
Since Pokémon names are often communicated in written forms, and since the previous Pokémonastics experiments used orthographic stimuli, the current experiment followed that methodology (
An interested reader can find all samples from the posterior distribution yielded by the Bayesian model, which underlie the data presented here and the assessment of linearity, in the supplementary materials.
An anonymous reviewer offered a very interesting example which can be tested to address this specific question. To quote: “[m]eanings like ‘big,’ ‘small,’ ‘evolved,’ etc. are arguably linear and open-ended in scale. But meanings like ‘androgynous,’ for example, might not be linear in the same way, such that, e.g., pitch raising up to a certain point of a male voice can reliably signal it, but beyond a certain threshold, not so much.” We are not in a position to offer an explicit answer to this specific question—it needs to await another quantitative study. We also note, however, that even if we find a pattern that is described by the reviewer, that would still be a case of counting cumulativity, but it might be a case of (strongly) sub-linear cumulative pattern.
Yu Tanaka (p.c.) pointed out a potential challenge to this thesis in the context of Experiment 2. In that experiment, long forms had complex onsets (i.e., more segments) while medium and short form did not (i.e., less segments), and the sound symbolic effect at issue was sensitive to that difference. However, it was long believed in the formal phonology literature that it is coda consonants, not onset consonants, that contribute to metrical weight in phonology (e.g.,
Experiments 1 and 2 were conducted under the ethical approval granted by the first author’s institution. A subset of the participants for Experiment 2 was recruited from the UCLA experiment participant pool, which was approved by the second author’s institution. A consent form was provided to the participants before the experiments.
We are grateful to two anonymous reviewers for
This project is supported by the the JSPS grants #17K13448 and #18H03579, the research money granted to the Keio Institute of Cultural and Linguistic Studies and NINJAL collaborative research project ‘Cross-linguistic Studies of Japanese Prosody and Grammar’ to Shigeto Kawahara. This work is also supported in part by NSF Graduate Research Fellowship DGE-1650604 to Canaan Breiss.
The authors have no competing interests to declare.