Are experts born or made? A bit of both, study shows
Phoneticians, who are skilled at identifying the subtlest of differences between sounds, appear to owe their expertise to a combination of innate skill and training, new research shows. As well as suggesting that some people may be predisposed to choose careers that need a good ear, the findings have implications for the treatment of people with problems like developmental dyslexia. They could also prove useful in the area of second language learning. The study, which was partly funded by the EU through a Marie Curie International Incoming Fellowship, is published in the Journal of Neuroscience. It is well known that London taxi drivers have a larger hippocampus (part of the brain involved in navigation) than other people. Similarly, professional golfers display a different brain activity pattern to novices when planning a shot. However, as Narly Golestani of the University of Geneva in Switzerland explains: 'It's often hard to tell whether these differences have been shaped entirely by experience or whether a person's brain structure may influence the profession that they enter.' In this study, Professor Golestani, along with colleagues from University College London (UCL) and the Wellcome Trust Centre for Neuroimaging in the UK, studied the brains of phoneticians. Phoneticians are trained to identify speech sounds and transcribe them into the international phonetic alphabet. The job requires them to quickly identify even subtle regional accents. The researchers chose phoneticians for this study because they undergo training in adulthood and the amount of phonetic transcription training and experience can be accurately measured. The researchers compared magnetic resonance imaging (MRI) scans of the brains of 17 phoneticians with those of 16 healthy volunteers. They found clear differences between the groups in two areas of the brain, one of which appears to have been boosted by training, the other of which is fixed before birth. The left pars opercularis was larger in phoneticians than in the control group, and among the phoneticians, was largest in those with the most phonetic training. In other words, the size of this area was influenced by experience. The left pars opercularis lies in a region of the brain called Broca's area, which is well known to be involved in speech and language processing. Previous studies have suggested that the left pars opercularis is involved in phonetic processing, and in the extraction and manipulation of phonetic segments in verbal working memory. 'This phonetic segmentation process parallels some of the demands of phonetic transcription, where the ability to effectively parse and identify phonetic segments and to provide a one-to-one correspondence between sounds and symbols is very important,' the researchers note. The other area of the brain that was larger in the phoneticians than in the control group was the left transverse gyrus, part of the left auditory cortex. However, this time, the amount of training bore no relation to the size of this brain region in the phoneticians. In fact, the structure of the transverse gyrus is largely determined during pregnancy. 'The transverse gyri are thought to be established in utero; our results thus suggest that this gross morphological difference may have existed before the onset of phonetic training, and that its presence confers an advantage of sufficient magnitude to affect career choices,' the researchers state. According to the researchers, the findings suggest that innate predispositions and the brain's plasticity may interact 'in determining not only how experience shapes the human brain but also why some individuals become engaged by certain fields of expertise'. 'This intriguing study provides an insight into how language is processed in the brain and why some people many have more of a penchant towards languages,' commented the Head of Neuroscience and Mental Health at the Wellcome Trust, Dr John Williams, who was not involved in the study. 'It goes beyond being a merely curious finding to one which may in time help us understand also why some people have phonological difficulties, such as ... developmental dyslexia.'For more information, please visit: Wellcome Trust:http://www.wellcome.ac.ukJournal of Neuroscience:http://www.jneurosci.org/
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Switzerland, United Kingdom