Applied behavior analysis (ABA) has been used to help individuals with autism. The basic principle of this form of behavior modification is ________.

A) partial reinforcement
B) classical conditioning
C) negative punishment
D) shaping

ABA is based on the principle of shaping, which involves reinforcing each step toward a desired behavior until the behavior is fully formed. This can involve positive reinforcement (rewarding desired behavior) or negative reinforcement (removing an aversive stimulus when desired behavior occurs). The goal is to increase the occurrence of desired behaviors and decrease the occurrence of undesired behaviors. Partial reinforcement, classical conditioning, and negative punishment are not the basic principle of ABA.