Are There Cognitive Rhythms in Speech?

Two studies are presented which investigated whether spontaneous speech is characterized by the presence of a cognitive rhythm that consists of alternating phases of hesitancy and fluency. In the first study, cumulative phonation-silence graphs were generated from the tape recordings of 54 one-minute monologues. These phonation-silence graphs were presented to two judges who were asked to rate the graphs for the presence or absence of cognitive rhythm. The results showed that the judges considered cognitive rhythm to be absent. A similar procedure was used in a second study in which the graphs were produced from a further set of 48 one-minute monlogues. As before, the two judges considered cognitive rhythm to be absent. In addition, in the second study the judges were unable to distinguish a set of computer-generated random walks from the speaker-generated graphs. It is concluded that cognitive rhythms are no more typical of normal speech than they are of random walks, and that any claims about their presence in speech must be treated with great caution.