Historians and psychologists have identified an extreme reluctance on the part of most people to engage another individual with any force, particularly deadly force. For police officers, who may need to use deadly force on the job, any hesitation could prove fatal. Pavlovian conditioning involves rewarding trainees for taking the appropriate action in conjunction with the reinforcement of inclusion by peers and the approval of superiors and veteran officers. Operant conditioning techniques program into officers' behavior an automatic response to stimuli. This combination of training enables officers to respond successfully to deadly threats regardless of their inborn aversion to using force against other human beings. Officers experience a series of psychological responses following their programmed use of deadly force. Law enforcement agencies should assist officers in overcoming the negative emotions surrounding deadly force incidents and help them resume their lives with some sense of normality. Notes