The ironic effect of thought suppression refers to the phenomenon in which individuals trying to rid their mind of a target thought ironically experience greater levels of occurrence and accessibility of the thought compared with individuals who deliberately concentrate on the thought (Wegner, 1994, doi:10.1037/0033-295X.101.1.34). Ironic effects occurring after thought suppression, also known as rebound effects, were consistently detected by previous meta-analyses. However, ironic effects that occur during thought suppression, also known as immediate enhancement effects, were found to be largely absent. In this meta-analysis, we test Wegner's original proposition that detection of immediate enhancement effects depends on the cognitive load experienced by individuals when enacting thought suppression. Given that thought suppression is an effortful cognitive process, we propose that the introduction of additional cognitive load would compete for the allocation of existing cognitive resources and impair capacity for thought suppression. Studies (k = 31) consistent with Wegner's original thought-suppression paradigm were analyzed. Consistent with our predictions, rebound effects were observed regardless of cognitive load, whereas immediate enhancement effects were observed only in the presence of cognitive load. We discuss implications in light of ironic-process theory and suggest future thought-suppression research.
Keywords: cognitive load; immediate enhancement effect; ironic effect; rebound effect; thought suppression.