You have a fox, a chicken and a sack of grain. You must cross a river with only one of them at a time. If you leave the fox with the chicken he will eat it; if you leave the chicken with the grain he will eat it. How can you get all three across safely?
Take the chicken over first. Go back and bring the grain next, but instead of leaving the chicken with the grain, come back with the chicken. Leave the chicken on the first side and take the fox with you. Leave it on the other side with the grain. Finally, go back over and get the chicken and bring it over.
Four cards are placed in front of you on the table, each with a number on one side and a color on the other. The visible cards show 3, 8, red and brown. Which cards should you turn over in order to test the truth of the statement that if a card shows an even number on one face, then its opposite face is red?
You’d need to turn over only the 8 and brown card. Only a card with an even number on one face and which is not red on the other face can invalidate the stated rule. If you turn over the 3 card and it’s not red, it doesn’t invalidate the rule, nor does turning over the red card and finding it has the label 3.
This test was devised by Peter Cathcart Wason and is known as the Wason selection task. Less than 10% of test subjects got it correct in two separate studies.
There are many English words that you can add an “s” to make it plural. But far fewer words become singular when you add an “s”. What are two examples of these much rarer words?
King Ferdinand has no immediate living relatives and decides to hold a contest to find a worthy successor when he dies. He gives a seed to every contestant and explains that the person with the healthiest and most beautiful plant will win the throne.
When the final day of the contest arrives, the king finds hundreds of plants of all shapes and sizes. However, he ignores them and awards the throne to a girl holding a pot with only moist dirt.
King Ferdinand was a kind and trusting man and wanted to be sure he found an honest heir. He gave small pebbles to all the contestants, claiming they were seeds. Therefore, any contestant with a plant had switched their “seed” in order to win. Everyone but the girl had been dishonest.
