Do emotions evoke characteristic facial expressions? For instance, is there one expression everyone uses to convey shock, and another commonly used to display disgust? In 1924, Carney Landis, a graduate student in psychology at the University of Minnesota, designed an experiment to find out.
Most of Landis's subjects were fellow graduate students. He brought them into his lab and painted lines on their faces so that he could more easily see the movement of their muscles. Then he exposed them to a variety of stimuli designed to provoke a strong psychological reaction. As they reacted, he snapped pictures of their faces. He made them smell ammonia, look at pornographic pictures, and reach their hand into a bucket containing slimy frogs. But the climax of the experiment arrived when he carried out a live white rat on a tray and asked them to decapitate it.
Most people initially resisted his request, but eventually two-thirds did as he ordered. Landis noted that most of them performed the task quite clumsily: "The effort and attempt to hurry usually resulted in a rather awkward and prolonged job of decapitation." For the one-third that refused, Landis eventually picked up the knife and decapitated the rat for them.
Landis's experiment presented a stunning display of the willingness of people to obey the demands of experimenters, no matter how bizarre those demands might be. It anticipated the results of Milgram's obedience experiment by almost forty years. However, Landis never realized that the compliance of his subjects was far more interesting than their facial expressions. Landis remained single-mindedly focused on his initial research topic, even though he never was able to match up emotions and expressions. It turns out that people use a wide variety of expressions to convey the same emotion — even an emotion such as disgust at having to decapitate a rat.
Below are the pictures he took of his subjects decapitating a rat. Note that one of the subjects (shown in slides 7, 8, and 9) was a thirteen-year-old boy suffering from high blood pressure. Doctors had referred the boy to the department of psychology because they suspected his symptoms were caused by emotional instability. Somehow he ended up in Landis' experiment.