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Hidden Emotions in the Sound of Words

Psychological study shows connection between emotional arousal and assignment of sound sequences as well as associative meanings

№ 123/2020 from Jul 14, 2020

On the basis of psycholinguistic experiments, an international group of researchers including a cognitive neuroscientist at Freie Universität Berlin, has been able to demonstrate that emotions play a central role in the associations between the sounds of words and their meanings. Hard sound combinations such as kiki are associated with a spiky shape, and soft sounds such as bouba are associated with a rounded shape. This effect is known to hold across age or cultural background. In the new study, sounds with their associated meanings were shown to be arousing or calming for the participants. Through the experiments, the research team was able to gain new insights into the role of emotion in children’s language acquisition as well as the development of language over the course of evolution. The findings were published in the journal Psychological Science.

The sound combinations bouba and kiki had already been used in previous studies, and a psychological effect was described: study participants linked the sound bouba with rounded shapes and connected kiki with tips or spikes. This effect can be observed regardless of the age or the cultural background of the test subjects. So far, however, it has remained unclear, why we see this matching preference. In the new study, the psychologists involved were able to gain deeper insights into this effect.

The findings of the new study suggest that there are many associations between sound and meaning in our vocabulary and that they are driven by emotional responses to auditory and visual input. The research team – headed by Dr. Arash Aryani from the Department of Psychology at Freie Universität Berlin as well as Erin Isbilen and Prof. Dr. Morten Christiansen, both from Cornell University (Ithaca, New York) – suspects that this connection also plays a role in children’s language acquisition. The findings may also provide clues as to how humans developed language over the course of evolution. The research underlines the importance of human emotions in the development of language and shows how the sound of words generates different levels of emotional intensity or arousal and maps out thoughts.

The research group led by Arash Aryani, Erin Isbilen, and Morten Christiansen assumed that the effect – the mental association of concepts, i.e., geometric shapes, with the phonetic sound of nonwords – is influenced by an important variable – the intensity of the emotions of the degree of neuronal excitement evoked in the subjects. They wanted to test this thesis with several psychological experiments.

The researchers asked the participants to rate their level of emotional intensity or arousal when viewing different forms and when hearing certain nonsense words. The visual and acoustic stimuli came from previous studies of the matching effect. In a second experiment, the researchers used newly created sound sequences with different arousal potential as a stimulus. In doing so, they were able to establish a clear connection and measure the effects they had expected: the spiky shapes and the hard-sounding nonwords associated with them had an emotionally very stimulating effect on the test subjects. Rounded shapes and the nonsense words like bouba had a calming effect.

These findings led the researchers to draw conclusions about the origins of language. The association between arousal, verbal sounds, and their meanings could have enabled early people to develop language skills. Accordingly, it would have been easier for them to associate sounds with meanings if this association also matched the appropriate emotional responses.

Further Information


Aryani, A., Isbilen, E.S. & Christiansen, M.H. (in press). Affective arousal links sound to meaning. Psychological Science. DOI: 10.1177/0956797620927967


Dr. Arash Aryani, Department of Education and Psychology, Freie Universität Berlin, Tel.: +49 30 838-58194, Email: Arash.Aryani@fu-berlin.de