Religious people need less evidence to believe a religious claim than a scientific claim, according to new research published in Social Psychological and Personality Science. But the study also indicates that religious people require less evidence than nonreligious people to believe a scientific claim.

The findings indicate that religious people tend to be less skeptical in general compared to the nonreligious.

“My general research interests focus on examining what people believe about reality and what factors contribute to how people develop, maintain, and revise those beliefs,” said study author Emilio Lobato, a PhD student in Cognitive and Information Sciences at the University of California, Merced.

“I have a particular interest in strange or unusual beliefs, whether they are about science, religion, conspiracies, history, superstitions, or the like. Pick a domain and it’s not hard to find some very weird beliefs that people have about it,” Lobato said.

“One part of why people believe the things they do is that people vary with respect to how committed they are to allowing empirical evidence to affect any given belief they may be asked to think about. This experiment that my colleagues and I conducted was a very neat and tidy way to touch on a lot of the things that interest me as a researcher at once.”

Lobato and his colleagues were interested in research showing that religious and nonreligious individuals tend to use different standard of evidence. In particular, a 2017 study found that religious people required less evidence for a claim that was presented in a nonscientific context as opposed to a scientific context.

In their new study of 703 participants, the researchers sought to replicate the findings and also examine the role of contradictory evidence.

Each participant was randomly assigned to read a short article that either described a group trying to cure an illness with a new medicine or described a group trying to cure an illness with prayers. In both cases, the participants were informed that one person had been cured after the group tested its method.

Then, the participants were either asked how many additional people would need to be cured before they could be certain the medication or prayer was effective, or were asked how many people would need to remain ill before they could be certain the medication or prayer was ineffective.

The researchers found that religious participants tended to need fewer replications than nonreligious participants to confirm a religious claim. Nonreligious participants, on the other hand, tended to need less evidence than religious participants to reject a religious claim.

Though there appears to be a bit of self-serving bias in both groups, Lobato told PsyPost that the findings were “a little more nuanced” than that.

“Our overall pattern of results suggests that religious people show a general tendency towards credulity when compared to nonreligious people. Relatively speaking, the religious participants in our study tended to set a lower bar to believe the claims we asked them about, and a higher bar to reject the claims we asked about,” he explained.

“By contrast, whether we’re talking about religious or scientific claims, nonreligious individuals in our study tended to be more skeptical than the religious people in our study. The nonreligious people tended to set a high standard before believing the claims we asked them about and a rather low standard before rejecting the claims we asked them about relative to the standards set by our religious participants.”

But there are still many questions to be answered about the relationship between religious belief and evidentiary standards.

“What we tested was how people treat one specific kind of evidence, namely replications of an effect, as it relates to fictitious claims — albeit claims of a kind that mirror real-world claims about experimental medicine or petitionary prayer,” Lobato said.

“It’s great that we replicated the original researchers’ results and expanded on it in a very straightforward way, but there are a lot of important questions left to ask. The most obvious question to my mind is would we find the same results if we asked about different kinds of scientific and religious claims?”

“Not all scientific claims or religious claims are like the ones we asked participants about. For instance, people may set very different standards of evidence for scientific or religious predictions about the far future (e.g., long-term effects of climate change, Armageddon) than they do for scientific or religious explanations for events that were just observed or happened far into the past,” Lobato told PsyPost.

“Additionally, ‘evidence’ itself is a very broad concept. There’s high-quality evidence, low-quality evidence, evidence derived from novel methods, evidence derived from traditional methods, true experimental evidence, quasi-experimental evidence, non-experimental evidence, and so on. It will be important to examine how people respond to different varieties of evidence. After all, that’s a lot closer to how people deal with evidence in the real world.”

Lobato added that the findings shouldn’t be interpreted as suggesting that nonreligious people tend to have better evidentiary standards than religious people — or vice versa. “A tendency towards credulity and a tendency towards skepticism are both important, so I don’t think it would be appropriate to derive value judgements from our results about either religious or non-religious groups,” he explained.

“Even if we’re occasionally wrong and end up believing something false from time to time, there are simple pragmatic advantages to just believing things, particularly things that aren’t immediately important, even if the evidence justifying that belief is flimsy. For instance, critically and skeptically evaluating every claim we encounter would dramatically slow down our day-to-day lives.”

“Conversely, a strong inclination towards skepticism is important to protect yourself from believing false claims, as there are sometimes real risks associated with believing things that are not true,” Lobato said.

The study, “Religiosity Predicts Evidentiary Standards“, was authored by Emilio J. C. Lobato, Shadab Tabatabaeian, Morgan Fleming, Sven Sulzmann, and Colin Holbrook.