Risk Communication Expert Ellen Peters Joins APPC as Visiting Scholar

Ellen Peters, a psychology professor at the Ohio State University who received her undergraduate degrees at the University of Pennsylvania, has returned to Penn this spring as a visiting scholar at the Annenberg Public Policy Center (APPC).

Peters, who directs the Decision Sciences Collaborative at Ohio State, has conducted research into how numeracy, the ability to understand and use numbers, influences decision making and how that ultimately affects various outcomes in people’s lives. Peters said she plans to work on understanding how numeracy affects the way people make decisions in domains where disagreement and false beliefs exist — for instance, whether or not to use a Zika vaccine.

Ellen Peters, visiting scholar at APPC.
Ellen Peters.

APPC director Kathleen Hall Jamieson and researcher Yotam Ophir recently published a study finding that false beliefs about a link between the MMR vaccine and autism influenced people’s intentions to use a Zika vaccine (which is still in development).

Peters, who has chaired the FDA’s Risk Communication Advisory Committee, conducted a related 2013 study examining the way that people with different numeric abilities misunderstood the risks of taking a prescription medication when they were presented with the risks in different formats. In the study, some people were shown the risks with numbers — like the frequency with which a side effect occurred (50 out of 100,000 people) or a percentage (14%). Others in the study were shown a simple list of side effects or characterizations of how likely side effects were to occur (very common or rare, etc.).

“If you give people numeric evidence of the likelihood of risks from a medication, people who are less numerate are much more likely than the highly numerate to overestimate the risks,” Peters said. “What’s interesting, though, is if you don’t give people the numeric evidence — if you give them a bland description like you’d see on a pharmaceutical ad, essentially a laundry list — most people overestimate. When you give them the numbers there’s a small difference in overestimations between the more and less numerate, but that difference is overshadowed by the 65-70 percent of people who overestimate risk when you don’t give the numbers.”

Peters is working on a book to be published by Oxford University Press on “innumeracy in the wild.” It’s about how people’s lack of math ability hurts them in everyday life, affecting health and financial outcomes, as well as the complex psychological issues that link numeracy to decision making.

Peters also will continue research with APPC research director Dan Romer on a series of studies evaluating the effectiveness of pictorial or graphic warning labels on cigarette packs. In a study published last year a team they led found that exposing smokers to the pictorial warning labels daily had a lingering effect and depressed smoking levels even a month following their trial use.

Finally, Peters is working Penn professors Cristina Bicchieri (philosophy and psychology) and Barbara Mellers (psychology and marketing) on a project examining perceptions of inequality and autonomy.

At Penn, Peters received her B.S. degree in economics from the Wharton School and a B.S.E. in systems engineering. Click here for more on her background and research.