Take a look at the photos on the right. A number of male subjects in an experiment conducted by researchers at Lund University, Sweden, and New York University were asked to choose which of the faces they found more attractive.

In a subsequent question they were asked to explain why they thought the face in the photo they had chosen was more attractive. Unbeknown to them however the researcher, in a magician like way, switched the photos. The majority of participants happily went about explaining why the they though that photo was the most attractive even though it was not the one they had chosen.

The crux of the matter is that, once we have made a decision, we reinforce the decision we have made by adjusting our expectations to suit the prior decision. Thus, when the participants were presented with a photo that they believed they had chosen they adjusted their expectations to support that choice.

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