How linguistic sounds and word meaning are connected: New DFG project

In earlier studies, Körner and Rummer were able to show that the emotional content of words depends not only on the emotional associations of the people or objects referred to (e.g. vacation as something positive), but also on the sounds in the words themselves. In particular, muscle movements play an important role in the articulation of vowels such as i (as in the English word "cheese") or o (as in the German word "Tod"). The connection between linguistic sounds and emotional content is so interesting from a scientific point of view because it could partially explain the origin of human language. The expression of positive and negative emotions plays a prominent role not only in humans, but also in the animal kingdom and is a central object of communication. Charles Darwin has already published an important work on this subject.

The new project will examine in particular the hypothesis that the vowel i is associated with positive emotions. The hypothesized reason for this is that the articulation of i requires the contraction of the same facial muscles as smiling. It is therefore an interface between emotional facial expression and linguistic expression. Phonetic utterances and emotional state are thus directly linked on a symbolic level (and on the basis of a biological mechanism). Another hypothesis is that the vowel o is associated with negative emotions because its articulation prevents smiling (try smiling and saying o at the same time). This new research project is initially concerned with demonstrating the robustness and automaticity of these effects. It also aims to show that other sound-symbolic effects (such as the relationship between the use of certain vowels and the size of objects) are based on other mechanisms (in this case pitch).

An example of the project is a recent study by the University of Kassel. The study comprises two experiments involving 399 subjects and a corpus analysis. In the two experiments, the test subjects were shown faces with different facial expressions and had to give these faces (real) names. In the first experiment, the expression of the faces was either positive (smile) or negative (angry expression); in the second experiment, artificially generated faces of different attractiveness were presented (see figure). Following the naming by the test participants, the extent to which names for positive and negative faces differed in terms of the frequency of the linguistic sounds they contained was investigated. As expected, the names of positive faces contained the vowel i significantly more often than the names of negative faces. In addition, differences in the use of certain consonant groups were also identified (in further analyses): Thus, nasals (e.g. n or m) occur more frequently in names for positive faces, while plosives (e.g. p or k) occur more frequently in names for negative faces.

The corpus analysis refers to a data collection in which test subjects had to rate names in terms of likeability on a scale of 1 to 7. For example, one of the questions was: "How likeable do you think the average bearer of the name X is?" Based on this data, it was shown that names with an i are rated significantly more positively than names with an o. Overall, the results of this study therefore confirm the assumption that the vowel i is positively associated.

Another recent study, which was also conducted at the University of Kassel, also shows that the association between names containing the vowel i and positive facial expressions is based on automatic and unconscious processes.

"With regard to the old question of whether sound and content are related in language, these results again provide clear evidence of a stable connection," says Dr. Anita Körner (first author of the first and co-author of the second study). Prof. Dr. Ralf Rummer goes one step further. In his view, this connection points to an important origin of human language, namely a coupling of emotional expression and articulation.

Rummer is head of the Department of General Psychology at the University of Kassel. He has been conducting experimental research into sound symbolism for more than 10 years.

Both studies are available online:
Körner, A., Röth, L., & Rummer, R. (subm.). Names with /i/ Suit Positive Faces: The Naming Paradigm. PsyArXiv. https://doi.org/10.31234/osf.io/m5fte

Schmidtke, D., Körner, A., Glim, S., & Rummer, R. (2024). Valence Sound Symbolism Facilitates Classification of Vowels and Emotional Facial Expressions. Journal of Experimental Psychology: Learning, Memory, and Cognition. Advance online publication.https://doi.org/10.1037/xlm0001389