Enhancing the believability of positive cognitions during EMDR installation: comparing positive cognition-only, working-memory taxation, and embodied imagination procedures

The installation phase of eye movement desensitization and reprocessing (EMDR) aims to strengthen the believability of an adaptive positive cognition, commonly measured with the Validity of Cognition (VoC) scale. Working-memory taxation plays a central role in several theoretical accounts of EMDR, yet it remains unclear whether dual-task demands support or interfere with VoC increases during installation. This randomised laboratory study compared three installation procedures: positive cognition with working-memory taxation, positive cognition only, and positive cognition with embodied imagination. The final sample consisted of 21 participants aged 18 to 25 years who completed a single EMDR-based laboratory session. VoC was assessed from the start of installation to after the third installation set (T3–T6) and analysed using a mixed-design repeated-measures ANOVA. VoC scores increased significantly during installation, indicating that participants experienced the positive cognition as more believable over time. However, the increase in VoC did not significantly differ between conditions, and the main effect of Condition was also not significant. A sensitivity analysis excluding one participant with an atypical course during desensitization and installation showed the same pattern of results. These findings suggest that VoC can increase from the start to the end of the installation phase, but there was no convincing evidence that one installation procedure was superior to the others. The results highlight the relevance of studying installation as a distinct phase of EMDR, while larger clinical samples are needed to examine whether differences between installation procedures emerge more clearly.

Dissertation/Thesis

English

van der Boog, Saar

Boog, S. van der. (2026). Enhancing the believability of positive cognitions during EMDR installation: Comparing positive cognition‑only, working‑memory taxation, and embodied imagination procedures.  (Master’s thesis, Rijksuniversiteit Groningen). University of Groningen