The tests, which lasted several months, sought to measure reactions to extreme stress and distress. Students wrote essays about themselves, were taken into a room and placed in a seat facing bright lights and a two-way mirror, hooked up to electrodes and then berated, belittled and subjected to brutal verbal attacks directed at their egos and beliefs. The experience and their reactions to it were filmed, and then played back to them repeatedly throughout the course of the study. Kaczynski’s brother said that, prior to his participation in the test, his brother had been emotionally stable.