The Choice Blindness Effect

The tendency to defend a choice even if our original choice has been covertly exchanged for something else.

In a fascinating study, volunteers were shown pairs of pictures of faces and asked them to choose the most attractive. Immediately after they made their choice, the people were asked to explain the reasons for their choices. Unknown to them, the scientists used a double-card magic trick to covertly exchange one face for the other, so they ended up with the face they didn't choose. You would think that they would notice such a big change in the outcome of a choice. But the result showed that in 75 percent of the trials, the participants were blind to the mismatch, even offering "reasons" for their "choice".