Cortical asymmetries in speech perception: what's wrong, what's right and what's left?

Over the past 30 years hemispheric asymmetries in speech perception have been construed within a domain-general framework, according to which preferential processing of speech is due to left-lateralized, non-linguistic acoustic sensitivities. A prominent version of this argument holds that the left temporal lobe selectively processes rapid/temporal information in sound. Acoustically, this is a poor characterization of speech and there has been little empirical support for a left-hemisphere selectivity for these cues. In sharp contrast, the right temporal lobe is demonstrably sensitive to specific acoustic properties. We suggest that acoustic accounts of speech sensitivities need to be informed by the nature of the speech signal and that a simple domain-general vs. domain-specific dichotomy may be incorrect.