THE INMATES WERE FROM A MINIMUM SECURITY INSTITUTION. THE HIDDEN CRIMINALS AND NONCRIMINALS ANSWERED ADVERTISEMENTS IN A CAMPUS NEWSPAPER. STRICT ANONYMINITY WAS ASSURED. A PERSONALITY INVENTORY FOUND THAT THE CRIMINAL GROUP WAS, OVERALL, MORE PATHOLOGICAL, THE NONCRIMINAL GROUP APPROACHED NORMAL MEASURES, AND THE HIDDEN GROUP WAS IN BETWEEN. THE HIDDEN CRIMINAL GROUP WAS ALSO MIDWAY BETWEEN THE STRONG DEPENDENCE OF EXTERNAL STIMULAE OF THE CRIMINAL GROUP AND THE MORE INDEPENDENT THINKING OF THE NONCRIMINAL. THERE WAS NO DIFFERENCE AMONG THE GROUPS IN THE MEASURE OF MEAN FIELD DEPENDENCY. HOWEVER, ON THE MOTOR CONTROL TESTS THE HIDDEN CRIMINAL GROUP PROVED QUITE DIFFERENT FROM THE OTHERS. AS HAS BEEN FOUND BY OTHERS, THE CRIMINAL GROUP HAD EXTREMELY POOR MOTOR CONTROL, THE NONCRIMINAL GROUP HAD GOOD CONTROL. THE HIDDEN CRIMINAL GROUP'S MOTOR CONTROL WAS FAR BETTER THAN EITHER OF THE TWO. SINCE THE CRIMES WHICH HAD BEEN HIDDEN WERE THEFT, INCOME TAX EVASION, DRUG OFFENSES, FRAUD, AND RECEIVING STOLEN GOODS, IT IS SUGGESTED THAT THE HIDDEN CRIMINAL'S GREATER CONTROL IS PRECISELY THE REASON THE CRIMES REMAINED HIDDEN. THE INTERACTION BETWEEN PERSONALITY VARIABLES AND SOCIAL MILIEU IS DISCUSSED IN DETAIL. CHARTS AND GRAPHS PRESENT STUDY DATA. AN EXTENSIVE BIBLIOGRAPHY IS APPENDED. (GLR)