The aim of the perception experiment reported here was to establish first whether English listeners expect longer preboundary syllable durations as the rank of the phonological boundary is higher; and, second, whether they expect longer preboundary syllable durations when the phonological boundary coincides with an intonation contour boundary. Judges were instructed to decide whether the duration of the pre boundary syllable was “all right”, “too long”, or “too short”. The stimuli were resynthesized utterances in which the durational characteristics of the boundary were varied. Although the results are not totally consistent, they suggest affirmative answers to both questions. The result for the second is particularly interesting, because the intonation contour boundary was not in all cases marked by a pitch movement on the experimental syllable itself. The perception of the intonation contour boundary can therefore take place on the basis of the listener’s interpretation of the utterance, together with the more global characteristics of the pitch contour. A third finding was that intonation contour boundaries elicited far more “call right” judgements than other boundaries. We tentatively suggest that this behaviour is the perceptual counterpart of the relaxation of articulatory control at the end of articulatory planning units.