The Entries, A through Z
AAMR American Association of Mental Retardation AAP Association of Applied Psychologists AAR 1. active avoidance reaction. 2. acceptor of action results. AAS ascending activating system AASECT American Association of Sex Educators, Counselors and Therapists AAT Auditory Apperception Test Ab antibody aba adrenergic blocking agent ABAB design An experimental design that compares two independent variables (A and B). Shifting experimental conditions from A to B and then back to A and then back to B to investigate the differing effects of each variable. Also known as ABAB counterbalancing/order/ sequence.