Vlaev, I., Chater, N., & Stewart, N. (2008). Seeing is not enough: Manipulating choice options causes focusing and preference change in multiattribute risky decision making. Journal of Behavioral Decision Making, 21, 556-574.

We show that preferences depend on the attributes that can be directly manipulated when people need to integrate multiple sources of information because direct manipulation causes focusing bias. This effect appears even when all relevant information is simultaneously and explicitly presented at the time the decisions are made. Participants decided how much to save, what investment risk to take and observed the future financial consequences in terms of the mean and variability of the expected retirement income. Participants who manipulated only the future income distribution saved more and took less risk. This effect disappears when the risk-related variables are removed, which indicates that task complexity is a mediator of such focusing effects. A more balanced trade-off between the choice attributes was selected when all attributes were manipulated. However, when there is a dichotomy between manipulating versus observing choice attributes, then decisions were based mostly on the manipulated attributes.

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