THIS NATURALISTIC STUDY OF ANTISOCIAL BEHAVIOR USED A 'FORGOTTEN' BOTTLE OF AN EXPENSIVE SHAMPOO TO DETERMINE THE LIKELIHOOD OF FEMALE UNDERGRADUATES TO ENGAGE IN PETTY THEFT. IN 10 CASES THE SUBJECT WAS ALONE, IN 10 A BYSTANDER COULD IDENTIFY HER, AND IN 10 THE BYSTANDER REMAINED ANONYMOUS IN A SHOWER STALL. THE AMOUNT OF SHAMPOO STOLEN WAS THE MEASURE. THE WHOLE BOTTLE WAS STOLEN IN THREE 'ALONE' AND IN TWO 'BYSTANDER ANONYMOUS' SITUATIONS. NINE GIRLS STOLE NOTHING (ONE ALONE, THREE IN BYSTANDER ANONYMOUS, AND FIVE IN BYSTANDER IDENTIFIABLE). IN THE REMAINING CASES SIGNIFICANTLY MORE SHAMPOO WAS STOLEN WHEN THE GIRL WAS ALONE THAN WHEN A BYSTANDER WAS PRESENT. HOWEVER, THERE WAS NO SIGNIFICANT DIFFERENCE IN BEHAVIOR BETWEEN THE TWO BYSTANDER GROUPS. IT IS CONCLUDED THAT THE PRESENCE OF BYSTANDERS INHIBITS PETTY THEFT. A BIBLIOGRAPHY IS INCLUDED. (GLR)