Choice-based conjoint is a popular technique for characterizing consumers' choices. Three eye-tracking studies explore decision processes in conjoint choices that take less time and become more accurate with practice. These studies reveal two simplification processes that are associated with greater speed and reliability. Alternative focus gradually shifts attention toward options that represent promising choices, whereas attribute focus directs attention to important attributes that are most likely to alter or confirm a decision. Alternative and attribute focus increase in intensity with practice. In terms of biases, the authors detect a small but consistent focus on positive aspects of the item chosen and negative aspects of the items not chosen. They also show that incidental exposures arising from the first-examined alternative or from alternatives in a central horizontal location increase attention but have a much more modest and often insignificant impact on conjoint choices. Overall, conjoint choice is found to be a process that is (1) largely formed by goal-driven values that respondents bring to the task and (2) relatively free of distorting effects from task layout or random exposures.
Meissner, M., Musalem, A., & Huber, J. C. (2016). Eye tracking reveals processes that enable conjoint choices to become increasingly efficient with practice. Journal of Marketing Research, 53(1), 1 - 17. https://doi.org/10.1509/jmr.13.0467