A speech rate measure of laboratory induced affect: the role of demand characteristics revisited.

Abstract

The study examined the effects of mood shift on a behavioural measure to investigate an ongoing question in the mood induction literature: Whether changes in performance following laboratory based mood induction procedures reflect genuine changes in affective state, or whether such changes can be generally attributed to the demand characteristics of the experimental situation. Prior to mood induction 40 subjects were assessed on self-spaced and maximal performance articulation tasks. Following mood induction articulation rates were again recorded. It was hypothesized that while there is considerable scope for experimental demands to influence self-paced tasks, by contrast maximal performance tasks should either reduce or eliminate demand characteristics. The results indicated that maximal articulation rate was sensitive to mood induction in that performance was retarded by the depressogenic procedure and accelerated by the elation-inducing procedure. Additionally, within-subject changes in speech rates correlated with conventional self-report measures of affective state. Interestingly, the speeded task appeared more sensitive to the mood manipulation than the self-paced task where demand characteristics had been expected to exert their greatest effect. It is concluded that these results corroborate the view that laboratory based induction procedures do promote true affective change and indicate that the speeded articulation task constitutes an effective indicator of that change.