ITHACA, N.Y. -- Flu infections are rising sharply across the United States, contributing to at least 81,000 hospitalizations and 3,100 deaths so far this season , according to the U. S. Centers for Disease Control and Prevention. As flu outbreaks increase, why are people getting vaccinated at lower rates, seemingly against their self-interest?
A Cornell psychology professor argues in new research that scholars of rational decision-making and many public health professionals have misunderstood how people make such decisions: based less on raw facts than intuition about them, and how that "gist" aligns with their core values.
In a pair of studies testing competing theories, two general questions that elicited participants' overall sense of risks and benefits explained vaccine hesitancy significantly better than the more precise, quantitative measures long favored by economists and psychologists. Categorizations of risks and benefits simply as none, low, medium or high significantly predicted whether people intended to get a vaccine or not. Study participants who perceived benefits as none or low, or risks as medium or high, tended to not vaccinate, for example.
"We make decisions based on the bottom-line gist of information: What does all this information boil down to? What's the decision really about?" said Valerie Reyna , the Lois and Melvin Tukman Professor of Human Development in the Department of Psychology and College of Human Ecology. "If we know the essence of how someone feels about these ideas, we can explain and predict their intentions with respect to vaccination."
Reyna, director of the Lab for Rational Decision Making , is the first author of " A New Look at Vaccination Behaviors and Intentions: The Case of Influenza ," published Nov. 29 in Behavioral Sciences.
Classic decision theories – with names like "reasoned action" and "planned behavior" – emphasize tradeoffs between good or bad outcomes and their probabilities, assuming that rational mechanisms explain and predict behavior. Newer "dual process" theories contrast impulsive and deliberative systems, suggesting people make better decisions when engaging the latter.
"All of these modern models essentially augment that core idea of a rational person making a decision about vaccination," Reyna said. "Somehow, that doesn't seem to describe the current context we're in for most people."
As a developer of "fuzzy trace" theory, Reyna proposes that two key processes drive decision-making: encoding of literal facts, and creation of meaning about those facts based on one's background and experiences.
The new research asked more than 700 college students and nearly 200 community members whether they had received a flu vaccine in the past year or intended to get one (substantial numbers in both samples were unvaccinated). Participants answered questions relevant to classic, dual process and fuzzy trace theories, including about their knowledge of and access to flu vaccines; their precise perception of risk on a scale from zero to 100; and their overall sense of the vaccine's risks and benefits.
Among the younger adults, vaccine knowledge and accessibility explained only 14% of the variation in intentions to get flu vaccines. That total jumped to 58% when considering responses to the gist questions. In the community sample, similarly, gist questions improved the ability to predict vaccination intentions from 57% to 80%.
"Part of our mind looks at details and precise facts, but the other part of our mind looks at the bottom-line, qualitative gist – and that's the more determinative part," Reyna said. "People form a global impression of what they are told and experience, for example, 'Overall, I think the benefits from vaccination are high and the risks are nil.' That would be a gist for people who get vaccinated, and that's what we showed."
The research suggests opportunities to reduce vaccine hesitancy through sustained communication that incorporates gist principles, in contrast to prevailing approaches that rely on lists of facts and trust in experts. Sharing basic background knowledge – such as the difference between viruses and bacteria, or how vaccines naturally enlist immune systems – is essential but not sufficient, Reyna said. Facts must be put into context to enable a conceptual, gist understanding. Then practitioners must explain how vaccine risks and benefits map onto core values – a desire to keep family and neighbors safe, for example, or to make free and informed choices.
"If you follow that recipe, you will be much more likely to make a difference with people, according to our research," Reyna said. "You have to take the right approach, and it's fundamentally different from what we're currently doing."
The research received support from the National Institute of Standards and Technology; the U.S. Department of Agriculture; and the Institute for Trustworthy AI and Society , where Reyna is a lead faculty member.
