The Trolley Problem is a classic question of ethics and morality. It asks what you would do with a runaway trolley that will kill one person if it goes left or five track workers if it goes right. College professor EJ Masicampo discussed the problem with his psychology class recently, and when he returned home and found his two-year-old son playing with his wooden trains, he decided to see what the boy would do. Here’s the result:

For a full explanation of The Trolley Problem, listen to my 2013 conversation with David Edmonds, author of “Would You Kill The Fat Man?”