Exploring expectation effects in EMDR: Does prior treatment knowledge affect the degrading effects of eye movements on memories?

Description

Background:
Eye movement desensitization and reprocessing (EMDR) is an effective psychologi-cal treatment for posttraumatic stress disorder. Recalling a memory while simultaneously making eye movements (EM) decreases a memory’s vividness and/or emotionality. It has been argued that nonspecific factors, such as treatment expectancy and experimental demand, may contribute to the EMDR’s effectiveness.

Objective:
The present study was designed to test whether expectations about the working mechanism of EMDR would alter the memory attenuating effects of EM. Two experiments were conducted. In Experiment 1, we examined the effects of preexisting (non-manipulated) knowledge of EMDR in participants with and without prior knowledge. In Experiment 2, we experimentally manipulated prior knowledge by providing participants without prior knowledge with correct or incorrect information about EMDR’s working mechanism.

Method:
Participants in both experiments recalled two aversive, autobiographical memories during brief sets of EM (Recall+EM) or keeping eyes stationary (Recall Only). Before and after the intervention, participants scored their memories on vividness and emotionality. A Bayesian approach was used to compare two competing hypotheses on the effects of (existing/given) prior knowledge: (1) Prior (correct) knowledge increases the effects of Recall+EM vs. Recall Only, vs. (2) prior knowledge does not affect the effects of Recall+EM.

Results:
Recall+EM caused greater reductions in memory vividness and emotionality than Recall Only in all groups, including the incorrect information group. In Experiment 1, both hypotheses were supported by the data: prior knowledge boosted the effects of EM, but only modestly. In Experiment 2, the second hypothesis was clearly supported over the first: providing knowledge of the underlying mechanism of EMDR did not alter the effects of EM.

Conclusions:
Recall+EM appears to be quite robust against the effects of prior expectations. As Recall+EM is the core component of EMDR, expectancy effects probably contribute little to the effectiveness of EMDR treatment.

Format

Journal

Language

English

Author(s)

Marianne Littel
Kevin van Schie
Marcel A. van den Hout

Original Work Citation

Littel, M., van Schie, K., & van den Hout, M. A. (2017). Exploring expectation effects in EMDR: Does prior treatment knowledge affect the degrading effects of eye movements on memories? European Journal of Psychotraumatology, 8(Supplement 1), 1328954. doi:10.1080/20008198.2017.132895

Collection

Citation

“Exploring expectation effects in EMDR: Does prior treatment knowledge affect the degrading effects of eye movements on memories?,” Francine Shapiro Library, accessed October 22, 2020, https://emdria.omeka.net/items/show/24663.

Output Formats