The excellent book “The Illusionist Brain: The Neuroscience of Magic” talks about an experiment done with supermarket customers, where they were asked to sample and then choose between two different kinds of jam. After that decision was made, they were asked to try the jam they had selected again and then explain why they had selected it.
However, for the second tasting, the jams were switched and the subjects were trying the jam that they had rejected, not the one they had picked. Two thirds of the participants didn’t even notice that the jams were switched and happily justified why they had selected this new jam. This happened even when the flavours were as different as apple-cinnamon and grapefruit!
I’ve talked before about how “why” questions can be problematic and this is a perfect example. In this case, the people were doubling down on an answer that was completely wrong. This was not the jam they’d picked the first time, and yet they were completely convinced that it was, and were happy to provide justification for what they considered to be good decision making.
This particular effect is called choice blindness, and is defined as a cognitive bias where people fail to notice that the outcome of a decision differs from their original intention, often fabricating justifications for the manipulated result.
But it doesn’t stop there; the experiment had one more twist. When this was all done, they were given a questionnaire asking about their own decision making process.
“Among other questionnaire items, the subjects had to say exactly how they thought they would feel if they had participated in an experiment that tricked them in this precise way. Of course approximately 90% of the subjects said they would never fall for such a trick.”
Not only are we easily tricked, we’re highly confident that we can’t be tricked, and that blinds us to our own weaknesses.
If we want to make better decisions, we need to be very deliberate about that. It’s too easy to convince ourselves that we’re already great, and then to not notice when the decisions we made are actually quite poor.