Skip to content

The Four Card Problem – in a nutshell.

April 4, 2019

 

You are presented with four cards, with the face-up side on display, showing either a letter or a number. You are promised that each has a letter on one side and a number on the other.

Red Card displays the letter D

Orange Card displays the letter N

Blue Card displays the number 21

Yellow Card displays the number 16

You are now presented with the following statement: Every card with D on one side has 21 on the other side.

Exercise

a. What is the minimum number of cards needed to determine whether this statement is true? What are the colours of the cards you need to turn over to determine this?

b. Four cards are placed on a table, each of which has a number on one side and a patch of colour on the other side. The visible faces of the cards display 1, 4, red and yellow. What is the minimum number of cards you need to turn over to test the truth of the proposition that a card with an even number on one face is red on the other side?

3. Four cards are placed on a table, two of which display a number, 16 or 25. The other two cards display a soft drink and an alcoholic drink. The minimum age for drinking alcohol is 18. What is the minimum number of cards you need to turn over to test the truth of the proposition that a card with a number greater than 18 on one side has an alcoholic drink on the other side?

References and Links

The Famous Four Card Task. Social Psychology Network. https://www.socialpsychology.org/teach/wason.htm

Wason Selection Task. Wikipedia. https://en.wikipedia.org/wiki/Wason_selection_task

 

From → Nutshells, Puzzles

Leave a Comment

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: