December 2, 2016, by Suzanne
Eye Movements in Choice
They say the eyes are the window to the soul. Here at NIBS we’ve been using the eyes – or at least the way people move their eyes – as a route to understanding what happens when people make decisions. We invited people to the laboratory and recorded their eye movements. We worked on people making risk decisions, where they can win or lose money, and people making social decisions, where they compete (or cooperate!) with an opponent to win money.
In both cases we find a remarkably simple pattern: The more people look at an option the more likely they are to choose it. But they don’t seem to be doing things quite as we expected. They don’t pay more attention to more likely outcomes or to larger outcomes, or pay more attention to the outcomes where they can get an advantage over their opponent. But we are able to predict people’s choices from their eye movements.
And we did find that the most popular models of decision making were not consistent with the eye movement data. There is little evidence that people weight outcomes by their likelihood as they should according to expection-based models like expected utility theory. There is little evidence that people engage in the “I think that you think that I think”type reasoning as they should according to level-k and cognitive hierarchy theories. Instead our data point towards simple models in which evidence is collected from each fixation – each time people read about an outcome they could get – and added up over time until people have enough evidence to choose one option over the other.
Our work continues now by looking at eye movements in real everyday decisions, like choosing which movie to watch on Netflix or whether to take out that pay-day loan.
Professor Neil Stewart, University of Warwick, Department of Psychology.
Figure 2 (below) from ‘Eye Movements in Risky Choice’ shows clustering solutions. Each panel is a separate participant and each dot is a fixation.
Stewart, N., Gächter, S., Noguchi, T., & Mullett, T. L. (2016). Eye movements in strategic choice. Journal of Behavioral Decision Making, 29, 137-156.
Stewart, N., Hermens, F., & Matthews, W. J. (2016). Eye movements in risky choice. Journal of Behavioral Decision Making, 29, 116-136.
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