Petter Johansson is an associate professor in cognitive science, and together with Lars Hall he runs the Choice Blindness Lab at Lund University in Sweden. 
 
The main theme of Johansson's research is self-knowledge: How much do we know about ourselves, and how do we come to acquire this knowledge? To study these questions, he and his collaborators have developed an experimental paradigm known as "choice blindness." The methodological twist in these experiments is to use magic tricks to manipulate the outcome of people's choices -- and then measure to what extent and in what ways people react to these changes. The general finding is that participants often fail to detect when they receive the opposite of their choice, and when asked to explain, they readily construct and confabulate answers motivating a choice they only believe they intended to make. The effect has been demonstrated in choice experiments on topics such as facial attractiveness, consumer choice and moral and political decision making.