Evaluating the usefulness of Protection Motivation Theory for predicting climate change mitigation behavioral intentions among a US sample of climate change deniers and acknowledgers

Background: This paper summarizes data from 7 studies that used Protection
Motivation Theory (PMT) to guide climate messaging with the goal of
increasing climate-mitigating behavioral intentions.  Together,
these studies address 5 research questions. 1) Does PMT predict behavioral
intentions in the context of climate change mitigation?  2) Does
PMT work similarly for climate change deniers vs believers? 3) Are the
effects of threat and efficacy additive or multiplicative?  4)
Does adding measures of collective threat and efficacy improve the model
accuracy for a collective problem like climate change? 5) Can threat and
coping appraisals – and ultimately behavioral intentions – be shifted
through climate messaging?   Methods: Seven online
experiments were conducted on US adults (N = 3,761) between 2020 and
2022.  Participants were randomly assigned to a control condition
or to one of several experimental conditions designed to influence threat,
efficacy, or both.  Participants indicated their belief in
climate change, ethnicity, gender, and political orientation. 
They completed measures of personal threat and efficacy, collective threat
and efficacy, and behavioral intentions.  Results: Multiple
regressions, ANCOVAs, and effect sizes were used to evaluate our research
questions. Consistent with PMT, threat and efficacy appraisals predicted
climate mitigation behavioral intentions, even among those who deny
climate change. Different interactions emerged for climate deniers and
acknowledgers, suggesting that in this context threat and efficacy are not
just additive in their effects (but these effects were small). Including
measures of collective threat and efficacy only modestly improved the
model. Finally, evidence that threat and efficacy appraisals can be
shifted was weak and inconsistent; mitigation behavioral intentions were
not reliably influenced by the messages tested.  Conclusions: PMT
effectively predicts climate change mitigation behavioral intentions among
US adults, whether they deny climate change or acknowledge it. Threat
appraisals may be more impactful for deniers, while efficacy appraisals
may be more impactful for acknowledgers.  Including
collective-level measures of threat and efficacy modestly improves model
fit. Contrary to PMT research in other domains, threat and efficacy
appraisals were not easily shifted under the conditions tested here, and
increases did not reliably lead to increases in behavioral intentions.