Try, one day, to walk up to someone, maybe up to many people, and tell them that you think they have made a mistake in their most recent decision. You can even try to sugar-coat it by telling them that the reason for this mistake is not because they are stupid or negligent, but because this is just the way they are wired — just the way their brain works.

If you take this approach, chances are that you will not be chosen as the most popular person in the office. My guess is that people will view your comment in a very negative light, become very offended, and distance themselves from you.

Now think about another case:

You walk up to someone, maybe up to many people, and show them a visual illusion — something that causes them to see something differently from what it actually is. When you show them their mistake, you also tell them that the reason for their mistake is not because they are stupid or negligent, but because this is just the way they are wired — just the way their brain works.

If you take this approach my guess is that your popularity will not suffer, and in fact, you might be considered a fun and interesting person.

Why would people react so differently to being told that they made a mistake in their decision than in their vision?

I am not sure of the answer, but it is clear to me that our over-sensitivity to the fallibility of our decision making causes us to limit the negative feedback we give others (saying, for example, “You are wrong.”), and that it is also the main reason that we try so hard (despite the evidence) to consider ourselves rational.