Humans sometimes justify their choices after the fact. The line of reasoning goes something like this: “I chose this, so I must like it. I didn't choose this other thing, so it must not be so good.” In fact, decades of cognitive science research and centuries of philosophical and scientific postulations suggest that humans unconsciously decide to like (or dislike) something based on previously made choices.
But Lisa Feigenson, a co-director of the Johns Hopkins University Laboratory for Child Development, wanted to understand the roots of this tendency. She and her team gathered up some young subjects — non-verbal 1-year-olds — to determine if this shaping of preferences begins in early life. Because babies get so few choices and come pretty close to being a blank slate, Feigenson says, they make for the perfect subjects.