Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)



First Advisor

Johnny L. Matson


In the literature, self-injurious behavior and aggression are often lumped together collectively as maladaptive behaviors. This study examined the social skills characteristics between persons with self-injurious behavior, aggression and a control group using the Matson Evaluation of Social Skills in Persons with Severe and Profound Retardation (MESSIER). Persons engaging in self-injurious behavior were significantly different from persons engaging in aggression as well as from the control group on five of the six subscales. The self-injury group had lower scores on subscales measuring positive behaviors and higher scores on subscales measuring negative behaviors. As expected for persons engaging in aggression, scores on the subscales measuring negative behaviors were higher than the control group. In an unexpected finding, however, the means of the aggression group were significantly higher than the means of the control group. In a discriminant functional analysis (DFA), the scores from the General Negative subscale maximized the spread among the three groups and the scores of the General Positive subscale distinguished the self-injurious behavior and aggression groups from the control group. The DFA correctly classified 50% of the cases. An additional analysis examined the characteristics of a separate group of persons who engaged in both aggression and self-injurious behavior. Their group means were significantly different on the negative subscales only. The DFA suggested that the scores on the General Negative subscale best separated the two groups. The DFA correctly classified 80% of the cases. Implications for treatment outcomes are discussed and future research ideas are presented.