How Looking Affects Consumer Decisions

Findings published by a team of researchers from Freie Universität Berlin and Technische Universität Berlin in cooperation with the Berlin Social Science Center and Ohio State University

No 100/2019 from Apr 16, 2019

Everyday decisions, like which product to buy from the shelf at the store, depend on how much time a person spends gazing at an item beforehand, according to a study. The degree of influence that gaze allocation (how long someone looks at something) has also differs from person to person. People do not tend to buy the product they would otherwise consider the best choice for them. Instead, they often pick the item that they looked at the longest, as researchers from Freie Universität Berlin, Technische Universität Berlin, the Berlin Social Science Center, and Ohio State University have shown. A connection between gaze allocation and choice behavior was apparent in 92% of participants. It indicated that they were less likely to pick the best option. Only about 8% of the participants appeared unaffected by gaze allocation. The researchers hope that the results will help them better understand why choice behavior differs so greatly between individuals.

When people make common, everyday decisions they usually look to see what other options are available. For example, if they want to buy a candy bar, they need to know which candy bars the store has in stock. While gathering this information, they will typically gaze longer at certain candy bars. For some people, the length of time they look at something has a strong influence on their ultimate decision. They might not even pick the best candy bar for them, but rather the one that they spent the most time looking at.

Armin W. Thomas (Technische Universität Berlin and Freie Universität Berlin), Felix Molter (Berlin Social Science Center and Freie Universität Berlin), Ian Krajbich (Ohio State University), Hauke R. Heekeren (Freie Universität Berlin), and Peter N.C. Mohr (Freie Universität Berlin and Berlin Social Science Center) authored the study. The team took a new look at four data sets from previous studies and examined whether the relationship between gaze allocation and choice behavior differed between individuals and if it is possible to predict choice behavior based on that relationship. They developed a new mathematical model for their analysis that operates on the assumption that when making decisions people collect evidence for different options over time. They then select the option for which they have sufficient evidence most readily, says Peter N.C. Mohr, researcher at the School of Business and Economics at Freie Universität Berlin and head of the neuroeconomics research group at the Berlin Social Science Center. The new model is based on the idea that people tend to gather evidence for a given option more quickly while they are looking at it. The model makes it possible to determine just how different the relationship is between individuals, Professor Mohr explains. The stronger the relationship, the more likely a person is to choose the option that they gazed at longer, instead of the best option for them. If the relationship is weak, gaze allocation hardly affects a person’s decision.

Professor Mohr emphasizes the importance of the model as a means of predicting choice behavior, noting that their goal was not merely to describe the different levels of influence gaze allocation has. To this end, the team divided the data sets into two equal parts: They used one half to determine how much influence gaze allocation has on choice behavior for each participant based on the mathematical model. With the other half, they attempted to predict choice behavior as precisely as possible. The researchers were able to show that the model they developed could indeed accurately predict how individuals would choose according to the amount of time they spent looking at an option.


Thomas, A.W., Molter, F., Krajbich, I., Heekeren, H.R., Mohr, P.N.C. (2019). Gaze Bias Differences Capture Individual Choice Behavior, Nature Human Behaviour.


Peter N. C. Mohr, School of Business and Economics, Freie Universität Berlin, and Neuroeconomics Research Group, Berlin Social Science Center, Tel.: +49 30 838 60607, Email: peter.mohr [at] neuroeconomics-lab (p) de.