Why it’s apt – psycho-acoustically speaking – that Darth Vader wasn’t called Barth Vaber

The relationship between the meaning of a word and the letter strings of which it is comprised is usually thought to be arbitrary. That is, the meaning of a word is dictated by convention and the emotional tone of the speaker. Strip these away and the sounds of the letter groupings themselves – known as phonemes – are generally considered meaningless. At least that's been a popular view for some time.

But now a study has been published that challenges this account. Blake Myers-Schulz and his colleagues show that the shift in sound from some phonemes to others carries emotional meaning of its own, quite independent from word meanings or tone of voice.

Human speech creates sound at different frequencies. Myers-Schulz and his team focused on the changes in certain frequency peaks in speech – known as formants – as nonsense words were spoken. Specifically, they divided nonsense words into those in which the first two formants went from low to high (e.g. bupaba, pafabi, mipaba) and those in which this sound shift was reversed, going high to low (e.g. dugada, tatoku, gadigu). They were matched on many other sound features, such as plosives, nasality, intonation and volume.

Thirty-two adult participants were shown pairs of these nonsense words on a computer screen, one of which always went low to high, the other high to low (in terms of formant shifts). Together with the words, two pictures were shown, one positive, one negative (e.g. a cute puppy and a snarling dog). The participants' job was to allocate the two nonsense words to the two pictures in the way that seemed most appropriate. The key finding was that 80 per cent of the time, they matched the word that had the low-high sound shift with the positive picture and the high-to-low word with the negative picture.

It was a similar story when 20 more adult participants performed the same task but with the words spoken by a computer programme rather than shown visually. In this case, they matched the low-to-high nonsense words with the positive pictures on 65 per cent of occasions – still far more often than you'd expect based on chance alone.

The findings suggest that strings of phonemes (the sounds that comprise words) have an emotional quality of their own, quite separate from any word meaning or the tone or volume of an utterance. This emotional meaning is conveyed purely by the acoustic properties of the word as the sound frequencies change from one phoneme to the next.

There could be intriguing real-life applications for this research in terms of marketing and PR because the implication is that some words convey positive emotion simply by virtue of their acoustic properties, above and beyond any literal word meaning. "Even in artistic contexts, such as film and literature, these acoustic principles could be applied to evoke a particular emotional subtext," the researchers said. "Indeed our data suggest that 'Darth Vader' is an acoustically more appropriate name for an intergalactic miscreant than 'Barth Vaber'."

Further reading

Myers-Schulz B, Pujara M, Wolf RC and Koenigs M (2013). Inherent emotional quality of human speech sounds. Cognition and emotion, 27 (6), 1105-13 PMID: 23286242