The review, published in the journal Trends in Psychology, was conducted by Nicolas de Oliveira Cardoso, Thaiane Moreira de Oliveira, Luisa Massarani, Ketlin da Rosa Tagliapietra, and Wagner de Lara Machado, researchers affiliated with Federal Fluminense University, the Oswaldo Cruz Foundation, and the Pontifical Catholic University of Rio Grande do Sul. The team searched seven databases and applied the Cochrane risk-of-bias tool for randomized trials, known as RoB-2, to each of the twelve studies that met their inclusion criteria. RoB-2 is the current gold standard for evaluating whether the results of a randomized trial can be trusted, examining domains such as the randomization process, deviations from intended interventions, missing outcome data, measurement of outcomes, and selective reporting. Using it in the context of climate communication research is relatively unusual, and that is precisely what makes the review notable.

The trials the reviewers examined represent the leading edge of belief-change research. Several tested psychological inoculation, a strategy in which people are pre-exposed to weakened forms of misleading arguments so they can recognize and resist them later. Work by researchers such as Sander van der Linden and colleagues has suggested that inoculation messages can confer resistance to climate misinformation, and a 2024 study in Nature Human Behaviour tested inoculation strategies across twelve countries. Other trials in the review focused on correcting misinformation after exposure, comparing different correction formats and placements, including on social media platforms such as Instagram. Still others examined whether communicating the overwhelming scientific consensus on climate change—through plain facts, visual displays, or metaphors—could shift beliefs, building on the influential idea that perceived consensus acts as a gateway belief.

What the reviewers found was not that these ideas are wrong in principle, but that the evidence base supporting them is far shakier than the field’s enthusiasm would suggest. All but one of the twelve randomized trials received a judgment of some concern or high risk of bias under RoB-2. In practical terms, this means that for nearly every study, there were credible methodological reasons to doubt whether the reported effects reflected the true impact of the intervention. The reviewers highlight two biases as particularly prevalent: selection bias and instrumentation bias. Selection bias arises when the way participants are recruited or allocated produces groups that differ before the intervention even begins, so any observed difference in climate beliefs may stem from those pre-existing differences rather than from the message itself. Instrumentation bias, meanwhile, occurs when the measurement tools used to assess outcomes are flawed, unstable, or poorly adapted, distorting the apparent size of change between pre-test and post-test.

The connection between these biases and the field’s underwhelming results is more than coincidental, the authors argue. When trials are methodologically fragile, effects tend to shrink or vanish under more rigorous scrutiny, and the predominance of interventions with small or no effects may partly be a symptom of the biases themselves rather than a pure reflection of how malleable climate beliefs really are. This reframing matters. A pessimistic reading of the literature would conclude that people’s climate beliefs are simply resistant to change. The review suggests a more nuanced interpretation: the true effectiveness of belief interventions cannot yet be established with confidence, because the studies designed to measure that effectiveness are themselves compromised.

The reviewers also point to a striking geographic imbalance. The included studies came overwhelmingly from high-income countries, with the United States dominating the sample. This matters for generalizability. Climate beliefs are shaped by political systems, media environments, cultural values, and direct experience of environmental change, all of which vary enormously across contexts. An inoculation message calibrated for American audiences steeped in polarized media discourse may behave very differently in Brazil, India, or Nigeria, where the drivers of skepticism or concern about climate change can be entirely different. The authors call for future randomized trials to evaluate interventions in low- and middle-income populations, a gap they describe as essential if the field wants its findings to speak to the global public rather than a narrow slice of it.

On the measurement side, the review offers a constructive lead. The authors identified four psychometrically sound instruments for measuring climate change beliefs, tools that have undergone proper validation procedures for reliability and validity. Adopting such instruments, they argue, is essential for reducing instrumentation bias in future trials. The broader point echoes long-standing principles from psychometric theory: an intervention study is only as credible as the scale used to detect change. If a questionnaire’s wording, response alternatives, or scoring shift in meaning between measurement points, or if it was never validated in the population being studied, then apparent pre-test to post-test gains may be artifacts rather than genuine belief change. Research on question wording effects in climate surveys has shown how sensitive these measures can be, making the choice of instrument a first-order methodological decision rather than an afterthought.

To tackle selection bias, the reviewers recommend pre-test/post-test designs combined with clearly established cut-off points for climate belief levels. The logic is familiar from classic experimental design: measuring participants before randomization allows researchers to verify that groups are comparable at baseline and to adjust statistically for any residual differences, while predefined thresholds for what counts as a given belief level reduce researcher discretion in interpreting outcomes. The authors also sketch a forward-looking agenda, outlining directions for the design of future randomized controlled trials and for meta-analyses that would synthesize the evidence more rigorously. Their hope is that integrating these recommendations—better designs, better instruments, broader populations—could improve both the accuracy and the generalizability of the next generation of climate belief interventions.

The stakes of this methodological reckoning are considerable. Climate change is already producing measurable harms to physical and mental health, and the scientific consensus on its human causes is essentially complete. Yet public belief lags, sustained in part by organized disinformation and conspiracy narratives, which meta-analytic work has linked to reduced willingness to engage in climate-friendly behavior and political action. If the research community cannot demonstrate, with trials that survive bias assessment, which communication strategies actually work, then practitioners, educators, and policymakers are left choosing among interventions on the basis of weak evidence. The review does not claim that inoculation, consensus messaging, or debunking are useless; it claims something more unsettling—that the field does not yet know, because the trials testing them are too fragile to say.

There is, ultimately, a constructive message embedded in this critical one. The fact that eleven of twelve trials raised concerns is a sign of a young, fast-moving field that has prioritized creative ideas over methodological armor. The RoB-2 framework, validated measurement instruments, pre-registered designs with baseline measurement, and deliberate attention to underrepresented populations are all available tools; what the review demands is that they be used systematically. If future trials meet that standard, the field will finally be able to distinguish between interventions that genuinely move climate beliefs and those that merely looked effective in flawed studies. For a problem as urgent as climate change, knowing the difference may be one of the most valuable contributions psychology can make.

Subject of Research: Effectiveness and risk of bias in randomized controlled trials of interventions to change climate change beliefs

Article Title: Limited Impact of Interventions for Climate Belief: A Systematic Review Assessing Risk of Bias

Article References: de Oliveira Cardoso, N., de Oliveira, T. M., Massarani, L., da Rosa Tagliapietra, K., & de Lara Machado, W. (2025). Limited Impact of Interventions for Climate Belief: A Systematic Review Assessing Risk of Bias. Trends in Psychology. https://doi.org/10.1007/s43076-025-00485-5

Image Credits: AI Generated

DOI: 10.1007/s43076-025-00485-5

Keywords: climate change beliefs, systematic review, risk of bias, randomized controlled trials, psychological inoculation, misinformation, scientific consensus, environmental psychology, selection bias, instrumentation bias, psychometrics, climate communication

The idea behind the experiment rests on embodied cognition, a framework in cognitive science holding that thinking is not confined to the brain but is grounded in bodily states and sensorimotor experiences. According to this view, abstract concepts borrow their structure from concrete physical experience. Temperature is one of the most studied grounding dimensions: physical warmth has been linked to social trust and interpersonal closeness, while cold has been associated with alertness, psychological distance, and threat sensitivity. Because climate change is an abstract, temporally distant risk, researchers have long suspected that bodily cues—especially cold sensations, which mirror the literal subject matter of global cooling fears and physical threat—might make the risk feel more immediate and concerning.

In the original 2012 experiments, Lewandowski, Ciarocco, and Gately asked participants to chew temperature-inducing gum as part of what they believed was a taste test. Cinnamon-flavored gum produced sensations of warmth, mint-flavored gum produced sensations of cold, and control participants chewed flavorless gum. Those who felt cold reported greater concern about climate change, greater willingness to volunteer for an environmental organization, and a larger intended time commitment than controls. The findings were arresting, but they arrived from a discipline now wrestling with a well-documented replication crisis, and embodied cognition research has been singled out as an area particularly vulnerable to failures of reproduction. Machery’s recent assessment of the field catalogues how many classic embodiment effects have failed to hold up under stricter experimental controls, making an independent test of the gum effect scientifically important rather than merely curious.

The replication team introduced three methodological improvements designed to address the most obvious weaknesses of the original work. First, rather than relying solely on undergraduates—the famously unrepresentative ‘WEIRD’ population of Western, educated, industrialized, rich, democratic societies—they recruited a community sample alongside a student sample, allowing them to test whether the effect generalizes beyond young, highly educated participants. Second, they added a bubble-gum condition, a flavor that carries temperature associations for some people but is far weaker than mint or cinnamon, to separate the effect of chewing itself from the effect of temperature-inducing flavors. Third, and critically, experimenters were blinded to which gum each participant had received, since evidence shows that unblinded experimenters can inflate effect sizes by unconsciously influencing participants or their own data recording.

The procedure mirrored the original study closely. All gums were white, identical in shape, and stored in sealed containers, and participants were told they were taking part in a taste test. A total of 116 people took part: 58 undergraduates with a mean age of about 21, and 58 community members with a mean age of about 37, roughly 41 percent of whom held a university degree. Participants were equally divided across the three flavor conditions and, while chewing, completed a ten-item survey measuring climate change risk perception, concern for social issues in general, willingness to volunteer for a climate organization, and the perceived temperature of the gum. Only after the session ended did the experimenter identify the flavor using a hidden marker inside the container.

The manipulation worked. Sixty-one percent of participants who chewed cinnamon gum reported feeling heat, compared with just 5 percent in the mint condition and 21 percent in the bubble-gum condition, while 57 percent of the mint group reported sensations of cold against 5 percent of the cinnamon group and 15 percent of the bubble-gum group. Importantly, perceived and actual room temperatures did not differ across conditions, ruling out ambient temperature as an alternative explanation. The stage was thus set for a clean test of whether the induced temperature sensations moved climate attitudes.

The headline result partially replicated the original study. Participants who chewed mint gum reported significantly greater concern about climate change than those who chewed bubble gum, with a small overall effect size. The effect was driven entirely by the undergraduate sample, where it was moderately strong, whereas the community sample showed no reliable difference across conditions. In a further echo of the original findings, gum flavor had no effect on concern about unrelated social issues, supporting the specificity of the manipulation—it was climate concern, not general negativity, that shifted. On pro-environmental behavior, participants in the mint condition were more willing to volunteer for a climate organization, with 48 percent expressing willingness compared with 26 percent in the cinnamon condition and 24 percent in the bubble-gum condition, a pattern that held across both samples.

Yet the replication also revealed sharp limits. Unlike the original study, the sensation of cold did not increase the number of hours participants said they would volunteer, a result that remained non-significant even after sensitivity analyses excluding extreme outliers. The authors interpret this gap between intention and commitment through the lens of the well-known attitude–behavior gap in environmental psychology: concern about climate change is only weakly correlated with actual pro-environmental behavior, a relationship complicated by factors such as learned helplessness, perceived inefficacy of mitigation responses, education, and entrenched habits. Theoretical models such as the Theory of Planned Behavior and Value-Belief-Norm theory emphasize motivational and normative pathways from belief to action, and the findings suggest that a fleeting bodily sensation may nudge attitudes without activating the deeper mechanisms required for sustained behavioral commitment.

Why did the effect appear only in undergraduates? The authors point to research showing that younger people are more responsive to contextual climate cues, reflecting their developmental stage, active identity exploration, and heavy exposure to climate discourse in education and media. For students, climate change is a salient identity issue, so a cold sensation may more readily connect bodily threat cues with an already-primed mental representation of climate risk. Older community members, whose beliefs are more crystallized and shaped by diverse life experiences, appear far less susceptible. The result carries an important warning for the field: embodied interventions may work only for narrow populations, and generalizing effects from student samples to the public at large—as much of psychology has traditionally done—is a hazardous enterprise. The relatively small subgroup sizes in the new study also temper confidence, underscoring the need for larger and more diverse samples in future work.

The study did not control for confounds such as prior climate concern, political ideology, or environmental literacy, all of which are known to shape climate beliefs, and the authors flag this as a priority for follow-up research. Still, the broader lessons are clear. Embodied temperature effects on climate concern are real but fragile, cold-specific, and demographically bounded. The work reinforces growing skepticism about the robustness of classic embodiment findings while demonstrating exactly the kind of methodological rigor—community samples, neutral control conditions, and blinded experimenters—that can distinguish durable effects from artifacts. For anyone hoping that a stick of mint gum could substitute for climate communication, the message is sobering: bodily sensations may open a small window of concern, but converting that feeling into lasting engagement requires motivational and efficacy-building strategies that no flavor can deliver.

Subject of Research: The influence of embodied temperature sensations, induced by chewing gum flavor, on climate change beliefs and behavioral intentions.

Article Title: Climate change as a matter of taste? The influence of gum flavor and embodied cognition on climate change beliefs. Replicating Lewandowski, et al. (2012)

Article References: Climate change as a matter of taste? The influence of gum flavor and embodied cognition on climate change beliefs. Replicating Lewandowski, et al. (2012). (n.d.). https://doi.org/10.1007/s12144-026-10047-2

Image Credits: AI Generated

DOI: 10.1007/s12144-026-10047-2

Keywords: embodied cognition, climate change beliefs, chewing gum, replication study, embodied temperature, environmental psychology, attitude-behavior gap, risk perception, Current Psychology, experimenter blinding, undergraduate sample, climate concern