## Tuesday, November 4, 2014

### Wason Selection Test

You are shown a set of four cards placed on a table, each of which has a number on one side and a colored patch on the other side. The visible faces of the cards show 3, 8, red and brown. Which two cards must you turn over in order to test the truth of the proposition that if a card shows an even number on one face, then its opposite face is red?
Apparently 90% of the people fail.

The same article goes on to mention that given the right social context most people make the correct choice.
For example, if the rule used is "If you are drinking alcohol then you must be over 18", and the cards have an age on one side and beverage on the other, e.g., "16", "drinking beer", "25", "drinking coke", most people have no difficulty in selecting the correct cards...

Disconnected Pappus said...

8 and red? I feel confused. Might be the beer from last night

Sachin Shanbhag said...

8 and brown.

Anonymous said...

The brown card can't have an even number on the other side, and the 8 card has to have red on the other side. The other two cards don't matter.

Sachin Shanbhag said...

Yeah, that is the idea. I think there is a tendency to turn over the red card, looking for confirmatory, rather than disconfirmatory evidence.