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), Prof. Dr. Ian Krajbich (Ohio State University), Prof. Dr. Hauke R. Heekeren (Freie Universität Berlin), and Prof. Dr. 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 Prof. Dr. 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.