Useful Delusions: The Power and Paradox of the Self-Deceiving Brain

by Shankar Vedantam

In 1979, the psychologists Lauren Alloy and Lyn Abramson decided to test this question on patients with one of the most common metal illnesses—depression. They wanted to see if these people were in fact less connected to reality than people who were healthy. The researchers set up an experiment. Subjects with and without depression were asked to press a button next to a blinking green light. Volunteers were asked to judge how much influence their button pressing had over the light’s blinking. Traditionally, people suffering from depression were thought to harbor an unrealistically negative view of the world—a delusional negativity was seen to be the cause of their despondency. Alloy and Abramson were surprised to find depressed people showed a “surprising degree of accuracy” in judging how the blinking light was affected by their manipulation of the button. Meanwhile, the non-depressed subjects consistently overrated their ability to control the blinking light. In other words, the gap between the groups was not caused by the healthy group seeing reality clearly and the depressed people seeing the world with delusional pessimism. No, the “healthy” group had a delusion of control while their “unhealthy” counterparts were seeing reality clearly. The subtitle of the psychologists’ paper was “Sadder but Wiser.” Subsequent studies in settings far more consequential than labs with blinking lights have reinforced Abramson and Alloy’s findings: People with depression and some other...