WITHIN THE PSYCHOBIOLOGY OF PUNISHMENT AND DETERRENCE, THE ORGANISM IS A CRITICAL VARIABLE. EACH INDIVIDUAL IS DIFFERENT IN BRAIN STRUCTURE, PAST EXPERIENCE, GENETIC INHERITANCE, AND PRESENT ENVIRONMENTAL CONDITIONS. PUNISHMENT MAY WORK TO DETER, BUT ONLY UNDER SPECIFIC CONDITIONS FOR A PARTICULAR INDIVIDUAL. THE IMPACT OF A PAINFUL STIMULUS ON A MALE WILL DEPEND ON HIS TESTOSTERONE LEVEL, AMONG OTHER FACTORS. THE IMPACT OF STIMULATION ON A FEMALE WILL DIFFER DEPENDING ON THE MENSTRUAL CYCLE. A PERSON WHO HAS EXPERIENCED PAIN AND FRUSTRATION ALL HIS LIFE WILL BEHAVE DIFFERENTLY FROM ONE WHO HAS NOT. THE IMPACT OF A STIMULUS ON A RESPONSE DEPENDS ON (1) THE PAST GENETIC HISTORY OF THE INDIVIDUAL UNDER STUDY, (2) THE PAST CONDITIONING OF THE INDIVIDUAL, (3) THE PRESENT STATE OF INTERACTION OF ORGANISM AND ENVIRONMENT, AND (4) THE FUTURE CONTIGENCIES ATTACHED TO RESPONSE PATTERNS. PUNISHMENT AND DETERRENCE CAN ONLY BE UNDERSTOOD WITH AN INTERDISCIPLINARY THEORY OF BEHAVIOR BASED ON BIOLOGY, PSYCHOLOGY, AND SOCIOLOGY, WITH MAJOR COMPONENTS INVOLVING BEHAVIORAL GENETICS AND PSYCHOBIOLOGY. HENCE, A THEORY OF LEARNING IS NEEDED, SINCE BEHAVIOR IS LEARNED. DETERRENCE THEORY ATTEMPTS TO EXPLAIN HOW INDIVIDUALS LEARN TO AVOID CERTAIN STIMULI. LEARNING IS A BIOCHEMICAL CODE IN THE BRAIN; THUS A PERSON IS DETERRED IF THE PROPER CODE IS IN HIS BRAIN. THE EFFECT OF PUNISHMENT ON AN ORGANISM IS THEN A MOST COMPLEX BIOSOCIAL PROCESS. RESEARCHERS MUST MOVE BEYOND PERCEPTION AND SURVEY DATA AND VERBAL REPORTS AS MEASUREMENTS OF ENVIRONMENTAL IMPACT ON BEHAVIOR AND DEVELOP THE CAPABILITY FOR TRACING A PAINFUL STIMULUS INTO THE ORGANISM TO THE ASSOCIATIONAL AND MOTIVATIONAL AREAS OF THE BRAIN AND THEN TO THE MOTOR CENTERS AND TO BEHAVIOR. FORTY-EIGHT REFERENCES ARE SUPPLIED. (AUTHOR ABSTRACT MODIFIED--MHP)