Examining the persuasive effect of metaphor use in psychotherapy: An experimental test of contributing factors

Abstract

Research suggests that metaphors can facilitate attitude change in psychotherapy. Based on social influence theory (Strong, 1968) and the Elaboration Likelihood Model (ELM; Petty & Cacioppo, 1986) of persuasion, this analogue study tested the impact of metaphor use in the context of advice as a therapeutic intervention. In an experimental design, 138 adult participants were randomly assigned to observe a brief videotaped vignette in which a therapist’s advice to a client either did or did not include a novel metaphor. After observing the video, participants completed a measure of therapist credibility, the Counselor Rating Form-Short Version (CRF-S; Corrigan & Schmidt, 1983), the Cognitive Involvement subscale from the Elaboration Likelihood Model Questionnaire (ELMQ-CI; Heppner et al., 1995), and rated the impact of the advice on a modified Tasks Impact subscale from the Session Impact Scale (SIS-TI; Elliott & Wexler, 1994).

It was hypothesized that (a) advice that included a metaphor would predict greater advice impact (SIS-TI), over and above perceived therapist credibility (CRF-S), (b) credibility would also predict advice impact, and (c) the relation between metaphor use and advice impact would be mediated by greater cognitive involvement with the advice (ELMQ-CI). Results supported the second hypothesis only; the relation between metaphor use and advice impact was nonsignificant, but perceived credibility did predict advice impact, accounting for 20% of the variance. Although the third hypothesis was not tested due to the lack of a direct effect, additional analyses showed that, with CRF-S scores covaried, metaphor use significantly predicted ELMQ-CI scores, which in turn significantly predicted SIS-TI scores. These findings suggested that the use of a metaphor may increase the client’s cognitive elaboration of a therapist’s advice, and greater cognitive elaboration may prompt acceptance of that advice. In other words, consistent with ELM, cognitive involvement (central route processing) seems to account for attitude change, with metaphors potentially prompting greater cognitive involvement. However, in this study, metaphor use was not predictive of greater attitude change. Results are discussed in light of the study’s strengths and limitations, their implications for theory, practice, and future research.