An integral part of Skinner's behaviorism studies, a Skinner box contains a lever and a small tray outside the chamber. The lever can be pressed by the animal to gain a reward (like food) or to avoid punishment (like electric shock).
A man named Phineas Gage suffered a massive head injury in 1848 when a iron rod entered his head, passing through the frontal lobe of his brain. Gage initially appeared to make a full recovery but later it was reported that his personality was drastically altered by the accident, giving early insight into how the human brain functions.
Hands holding two identical capsules, one of which is medically inactive (a placebo) while the other is a drug or medicine. Placebos are used as controls in clinical drug trials to counteract the psychological "placebo effect".