Kahan seconds having a “diverse set of experts” vouch for sound scientific data. According to his research, if different values fall on the same side of the issue (and the same values on different sides), the lay public are less likely to be polarized by the debate.
In a study of people’s reactions to scientific arguments about mandatory HPV vaccinations, “worldview” scales were used to categorize participants’ values (e.g., “individualistic” vs. “communitarian”). Experimental conditions included presenting pro- or con- arguments with profiles of “fictional male experts, whose appearance…and publication titles” were meant to evoke “distinct cultural perspectives.”
Shifts in participants’ positions depended less on the arguments than the arguers. Say participants read both of the following:
- Argument A that supported their view by an expert who shared their values
- Argument B that opposed their view by an expert who rejected their values
Then they tended to hold their view more strongly.
Now switch who makes the arguments. Say participants read:
- Argument B that opposed their view by an expert who shared their values
- Argument A that supported their view by an expert who rejected their values
Then they tended to hold their view less strongly.
Under the first condition, polarization among participants grew. Under the second condition, it shrank. Thus, in the latter case a presumed effect of motivated reasoning, as driven by participants’ defining values, appears to have been mitigated.
Kahan and his colleagues admit that the “counter-intuitive pairings of arguments and advocates” that characterize the second condition are unrealistic (even suspicious) outside the laboratory. Still, they think public discourse that includes “persons of diverse values on both sides of…the debate” is realistic and, based on other findings, could reduce polarization.
Public debate over climate change has become especially polarized. We might even worry it has become “personalized” almost beyond remedy. Finding people—preferably experts—of diverse values on both sides of the issue isn’t easy. So maybe motivated reasoning has us dug in too deep?
Kahan thinks there’s yet another way to advance debate. Experts aside, the evidence itself can sometimes be framed to affirm people’s values. In another study, Kahan and his colleagues found that participants with “individualistic values” who read (in order)
- a newspaper story about geoengineering (e.g., mechanically capturing atmospheric CO2)
- a Nature Science study warning of environmental risks associated with atmospheric CO2
were less dismissive of the Nature Science study than like-minded participants who read the study but not the story. Geoengineering is an alternative (or supplement) to government regulation of industrial carbon-emissions, which Kahan says “individualistic” persons tend to oppose. He also says geoengineering symbolizes something they value—”human resourcefulness.”