Iris’ main research interests are in the area of eating behaviour, focusing specifically on the effect of portion sizes on eating behavior. In her dissertation research, she investigated the portion size effect, which refers to the increase in energy intake that occurs when people are confronted with bigger portions or packs, compared to smaller ones. Iris’ work has shown that placing a serving size recommendation on the pack, reduces uncertainty about how much is appropriate to eat, and as a result weakens the portion size effect – but only if this is a pictorial serving size recommendation on which you can easily see the recommended amount, rather than a serving size recommendation in grams. In another project, Iris found that among restrained eaters, the portion size effect can be prevented by priming them with their dieting goal.
Iris graduated from Erasmus School of Economics with a MSc in Business Economics (cum laude), after which she worked in market research for five years. In 2012, she returned to university to pursue her PhD at the Erasmus Research Institute of Management (ERIM). The supervisory team consisted of Prof. Philip Hans Franses and Dr. Esther Papies. Iris defended her dissertation in April 2016, and currently holds a position as a consumer insight manager at Unilever.