College of Arts & Sciences

Date of Award


Document Type

Research Project Report

Degree Name

Master of Arts (MA)


Behavioral Science

First Advisor

J. Greenspan, Ph.D.

Second Advisor

Robert Rothstein, Ph.D.

Third Advisor

James M. Olson, Ph.D.


While nail-biting is not considered an important psychiatric symptom in the literature, it is an irritating and disfiguring behavior which calls for innovative intervention in its control. The subject in the present study was a 54-year-old female who spent an appreciable amount of time with facial make-up and hair grooming, but who often tried to hide her hands because of the disfigured appearance of her nails. In a ten-week study comparing the effects of positive and negative reinforcement, the subject was first rewarded for increasing her nail-biting behavior with tokens to be spent for "something to make her pretty". Then, in the second condition, she was negatively reinforced for increasing her non-biting behavior by removal of the aversive event of having her nails painted with an attention drawing shade of nail polish. She reached nail growth criterion in all five phases of positive reinforcement but only reached criterion in three of the five phases of negative reinforcement, showing an initial disinterest in working under the negative reinforcement condition. Transference of nail-biting energy to the fourth digits of each hand indicated a suppression of response that was not present in the positive reinforcement treatment, indicating that although escape or avoidance of an aversive event can be reinforcing, aspects of the punishment element still prevail.



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