The effect of chorpromazine on speech behaviour

Summary

The purpose of the experiments reported was to study the effect of Chlorpromazine on such cognitive functions as manifest themselves and have been shown by the investigator to be measurable in terms of verbal behaviour.

These were hesitation pauses in spontaneous speech which in previous work had been shown to reflect processes concerned with the selection of words and the formulation of meaning.

The experiments consisted in evoking, in normal and highly intelligent adults spontaneous utterance of speech at two levels of cognitive complexity, involving descriptive and general statements. Speech of this kind had been studied before and the two levels were shown to differ widely in pause duration. In the present investigation such speech was studied in conditions of No Drug, Sodium Amytal and Chlorpromazine.

The advantage of pause time in speech as a measure of cognitive changes under these conditions is that it makes possible a separation of the behaviour accompanying the processes concerned with achieving cognitive results from the quality of the results themselves. This enables us to gain a picture of the drug action in relation to the mechanism involved in cognitive activity apart from what it achieves.

The latter was assessed independently from judges' ratings of the cognitive quality of the statements made, level of generalisation being the criterion. Thus the drug effects could be studied separately for cognitive labour and for its efficiency in terms of cognitive achievement.

The results show the effect of Chlorpromazine on pause time, in contrast to Sodium Amytal, to be selective, varying in direction with individuals; the effect on the cognitive quality of the linguistic product shows itself to be linked to the effect of Chlorpromazine on pause behaviour, pause time appearing, under Chlorpromazine as under normal conditions, to be involved in generating complex verbal structures. Under Sodium Amytal, on the other hand, no such link between hesitation and information was in evidence.