Logic and hemlines

Each of the cards here has a letter on one side and a number on the other. Which two cards would you turn over to substantiate the rule that if there is a "k" on one side, there must be "2" on the other?

Eric Schwitzgebel, ever the skeptic, uses the Wason selection task to illustrate the point that even simple logical problems are conditioned by our psychology or sociology, and puts the test in a social context as proof.

In the abstract, we really are feeble animals.

To use a far less precise example, I think it's like showing up at a party to find, across the room, that fetching woman swathed in a little black dress, or that tall, broad shouldered and handsome man looking your way. While you may think the attraction makes perfect sense - the curves! the bearing! - it may be years, if ever, before you really know how much.

The correct choices, by the way, are the "k" and the "7".