CONVICTION RECORDS FOR SUBJECTS WERE OBTAINED FROM THE NATIONAL POLICE REGISTER AND THE PENAL REGISTER OF DENMARK. HIGH-RISK GROUP SUBJECTS WERE 207 CHILDREN OF SCHIZOPHRENIC MOTHERS. THE MEAN AGE OF THESE CHILDREN WAS 15.1 YEARS. THE CONTROL OR LOW-RISK GROUP CONSISTED OF 104 CHILDREN. IN 1962, NO SUBJECT FROM EITHER GROUP WAS SUFFERING FROM ANY MENTAL DYSFUNCTION. AS OF 1975, 39 MALES WERE ARRESTED AND CONVICTED FOR VARIOUS CRIMES AND 9 OF THESE WERE CLASSIFIED AS PSYCHOPATHS. SINCE VERY FEW FEMALES ACQUIRED CONVICTIONS RECORDS AND ONLY ONE FEMALE WAS CLASSIFIED AS PSYCHOPATHIC, FEMALES WERE ELIMINATED FROM THE SAMPLE. THIS LEFT A TOTAL SAMPLE SIZE OF 175 SUBJECTS. HEART RATE RESPONSES WERE EXAMINED FOR SUBJECTS CLASSIFIED ACCORDING TO CONVICTION RECORDS: NO CONVICTIONS; ONE CONVICTION; AND TWO OR MORE CONVICTIONS. IT WAS HYPOTHESIZED THAT CHILDREN WHO LATER BECAME CRIMINALS WOULD DEMONSTRATE, PRIOR TO THEIR CONVICTIONS, PHYSIOLOGICAL RESPONSES MORE CONDUCIVE TO ASOCIAL BEHAVIOR. MORE SPECIFICALLY, IT WAS ASSUMED THAT HEART RATE PATTERNS OF THESE CHILDREN WOULD SHOW LESS REACTIVITY, POORER CONDITIONING ABILITY, LESS GENERALIZATION, AND FASTER EXTINCTION TO STRESS THAN THE CONTROL GROUP WITH NO CONVICTIONS. FINDINGS INDICATED THAT SUBJECTS WITH TWO OR MORE CONVICTIONS WERE LESS AUTONOMICALLY RESPONSIVE DURING STRESS THAN SUBJECTS WITH NO CONVICTIONS OR SUBJECTS WITH ONLY ONE CONVICTION. ALTHOUGH HEART RATE DATA DEMONSTRATED A LIMITED CAUSAL RELATION TO CRIMINALITY, IT WAS DETERMINED THAT SOCIAL VARIABLES NOT CONSIDERED IN DETAIL IN THE STUDY, SUCH AS SOCIAL CLASS, PARENTAL CRIMINALITY, AND PEER GROUPS, ARE MORE IMPORTANT IN STUDYING THE ETIOLOGY OF CRIMINAL BEHAVIOR. TABLES AND FIGURES ARE INCLUDED. APPENDIXES CONTAINING ADDITIONAL DATA ON HEART RATE RESPONSES AND REFERENCES ARE CITED. (DEP)