Uncertainty is inherent to science and science communication. However, the evidence appears mixed regarding whether portraying uncertainty in science communication has positive or negative effects. We review a diverse range of experimental literature (k = 48; from 40 searches and 8000 retrievals), summarize the extant findings, and observe how the effects vary across four different types of communicated uncertainty (deficient, technical, scientific, and consensus uncertainty). The results indicate that most findings of negative effects (such as reduced credibility and beliefs) are from experiments that operationalized uncertainty as disagreement or conflict in science (consensus uncertainty). In this review, consensus uncertainty was never found to have positive effects. In contrast, uncertainty in the form of quantified error ranges and probabilities (technical uncertainty) in these studies has had only positive or null effects, not negative effects. We also highlight frequent moderators of the effects of uncertainty, such as prior beliefs and worldviews.
Keywords: experiments; framing; literature review; science communication; uncertainty.