We used a corpus of collaborative task oriented dialogues in American English to compare two units of rhythmic structure — pitch accents and syllables — within the coupled oscillator model of rhythmical entrainment in turn-taking proposed in [1]. We found that pitch accents are a slightly better fit than syllables as the unit of rhythmical structure for the model, but we also observed weak support for the model in general. Some turn-taking types were rhythmically more salient than others.