Difference between brain hemispheres not so strict
The difference between the rational left hemisphere and the emotional right hemisphere is by no means as strict as the popular view would have us believe. PhD candidate Jurriaan Witteman has published a study on this topic in Cognitive, Affective and Behavioural Neuroscience.
It is generally thought that the ‘rational’ left hemisphere is good at analysing language while the ‘emotional’ right hemisphere is good at perceiving emotion, explains PhD candidate Jurriaan Witteman. Speech melody, also known as prosody, can be used both to convey linguistic (purely informative) and emotional information. For example, one and the same sentence can express such additional information as anger or a question, depending on how it is uttered:
‘You have to take the train to Groningen!!!' Said in an angry tone
‘You have to take the train to Groningen?’ Said in a questioning tone
Witteman and his supervisors Niels Schiller and Vincent van Heuven at the Leiden University Centre for Linguistics (LUCL) and the Leiden Institute for Brain and Cognition (LIBC) were wondering whether the right and left hemispheres are indeed specialised in perceiving emotional and linguistic prosody, respectively. They investigated this in collaboration with the Neuro Imaging Centre (NIC) in Groningen.
The researchers asked test subjects to listen to both emotional and linguistic prosody while they measured the activity of the two brain hemispheres. They did so by using electroencephalography (EEG), which involves placing a cap with electrodes on the test subject’s head. The hemispheres were shown to be more or less equally active in both cases. This contradicts the popular idea of the linguistic left hemisphere and the emotional right hemisphere: the results show instead that both hemispheres are involved in processing emotional and linguistic prosody. These results are consistent with an earlier study conducted by Witteman which showed that both hemispheres are important for the perception of both forms of prosody.
A better understanding of the neural network involved in the perception of prosody may in the longer term contribute to the treatment of brain diseases which involve a disruption of this particular system. An example of such a condition is schizophrenia, in which people sometimes hear angry voices (hallucinations). A better understanding might also help to develop software which is able to recognise the emotional and linguistic information encoded in prosody. ‘For example, your computer might automatically start playing one of your favourite cheerful tunes if the software detects sadness in your voice,’ says Witteman. He expects to complete his PhD this year. He is currently also working as a postdoc at the Dutch Institute for Alcohol Policy where he is involved in research in the field of psychopharmacology.
The nature of hemispheric specialization for prosody perception. Jurriaan Witteman, Katharina S. Goerlich-Dobre, Sander Martens, André Aleman, Vincent J. Van Heuven, Niels O. Schiller. Cognitive, Affective, & Behavioral Neuroscience, February 2014
- Jurriaan Witteman
- Cognitive psychology
- Leiden University Centre for Linguistics (LUCL)
- Leiden Institute for Brain and Cogntion
- LIBC Junior