The manipulation of affect: A meta-analysis of affect induction procedures.

Affect inductions have become essential for testing theories of affect and for conducting experimental research on the effects of mood and emotion. The current review takes stock of the vast body of existing literature on affect induction procedures (AIPs; also referred to as mood inductions) to evaluate the effectiveness of affect inductions as research tools and to test theories of affect (e.g., the bipolarity hypothesis, negativity bias, positivity offset, and theories of emotionality and gender) using meta-analytic data. In doing so, we seek to address whether AIPs are effective for inducing affective states, what conditions maximize their effectiveness, for which emotions they are most effective, for whom they are most effective, and whether affect induction findings can provide insight into theories of affect. A meta-analysis of 874 samples and 53,509 participants suggests that affect inductions are effective on average (δ = 1.32), but this effectiveness varies with the type of affect induction, the emotion being induced, and the gender of the participants. Further, results indicate coupled activation where the induction of positive (negative) emotions leads to a corresponding reduction in negative (positive) emotions, which provides support for the bipolar continuum of positive and negative affect. Results also revealed a negativity bias in which individuals display stronger reactions to negative stimuli than positive stimuli. A practical guide in the choice of affect induction procedures for researchers is presented and implications for emotion theory are discussed. (PsycINFO Database Record (c) 2020 APA, all rights reserved).