Born with an Ear for Dialects? Structural Plasticity in the Expert Phonetician Brain

Are experts born with particular predispositions, or are they made through experience? We examined brain structure in expert phoneticians,individuals who are highly trained to analyze and transcribe speech. We found a positive correlation between the size of left parsopercularis and years of phonetic transcription training experience, illustrating how learning may affect brain structure. Phoneticianswere also more likely to have multiple or split left transverse gyri in the auditory cortex than nonexpert controls, and the amount ofphonetic transcription training did not predict auditory cortex morphology. 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 itspresence confers an advantage of sufficient magnitude to affect career choices. These results suggest complementary influences ofdomain-specific predispositions and experience-dependent brain malleability, influences that likely interact in determining not onlyhow experience shapes the human brain but also why some individuals become engaged by certain fields of expertise.