The perception of intonational emphasis: continuous or categorical?

A series of experiments was carried out to test the idea that there is a categorical difference between ''normal'' and ''emphatic'' accent peaks in English, rather than a continuum of gradually increasing emphasis. This idea builds on serveral studies previously published in this journal as well as a pilot study of our own. The experimental stimuli were all naturally spoken short utterances containing a single rising-fairing pitch accent, resynthesised with modified pitch range. In three classical categorical perception experiments we found good evidence of abrupt shifts in identification from normal to emphatic as pitch range increases, but little evidence of an associated peak in discriminability of stimulus pairs. This suggests that the normal/emphatic distinction may be ''categorically interpreted'' but not categorically perceived. Additionally, we report a consistent but puzzling order-of-presentation effect that bears further investigation. (C) 1997 Academic Press Limited.