Donald Baer earned his Ph.D. in 1957 from the University of Chicago. His doctoral advisor was Jacob Gerwitz. In the mid 1960s he was part of an "extraordinary group" of applied behavior analysts in the Department of Psychology at the University of Washington that included Sidney Bijou, Jay Birnbrauer and Bill Hopkins. At their laboratory clinic, known as the Developmental Psychology Laboratory, Baer and colleagues produced "dozens of seminal publications in applied behavior analysis" (Lovitt, 1993, p. 564): e.g., "The Effects Of Adult Social Reinforcement On Child Behavior" (Harris, Wolf, and Baer, 1964). At this time Baer considered himself part of "a small but ambitious disciplinary group dedicated to rigorous standards of proof, experimental technique, good measurement and the direct observation and thorough behavioral definition it required, and a theory consonant with those three values" (Baer, 1993, p. 570). As the story goes, the faculty at the Developmental Psychology Laboratory ultimately lost "a quite typical psychology civil war," leading to their mass exodus. Frances Horowitz, the new chair of the Department of Human Development at the University of Kansas, persuaded Baer to join their faculty. Baer recalls that he "was especially interested in recreating the intellectual climate of Bijou's Developmental Laboratory: a theory-driven commitment to the experimental analysis of the child's behavior most important to children, their society, and developmental theory; and the use of graduate students more as colleagues than servants" (Baer, 1993, p. 570). He was instrumental in recruiting other prominent behavior analysts to the faculty (e.g., Montrose Wolf, Todd Risley, and Barbara Etzel). Baer was a Roy A. Rogers Distinguished Professor at the University of Kansas.
Baer is a past editor of the Journal of Applied Behavior Analysis (1971) and former president of the Association for Behavior Analysis International (1980-81, formerly called the Association for Behavior Analysis). He has been a prolific and influential writer and researcher over the years. A search of the PsycInfo database between 1967-1998 revealed over 100 publications. Two of his articles, "Some Current Dimensions of Applied Behavior Analysis" (Baer, Wolf, & Risley, 1968) and "An Implicit Technology of Generalization" (Stokes & Baer, 1977), are very frequently cited references, respectively, in the history of the Journal of Applied Behavior Analysis. Another article, "The Development of Imitation By Reinforcing Behavioral Similarity To A Model" (Baer, Peterson, & Sherman, 1968) is a highly cited reference in the history of the Journal of Applied Behavior Analysis. During the 1960s Baer collaborated with Sidney Bijou to write two books on the topic of developmental psychology from a behavioral perspective: Behavior Analysis of Child Development (Bijou & Baer, 1978); Child Development II: Universal Stage of Infancy (Bijou & Baer, 1965). This work has played a crucial role in the history of behavior analysis (e.g., Martin & Pear, 1998; Michael, 1993). In his presidential address to the Association for Behavior Analysis, Michael (1980) recommended that mastery of both books be part of a minimal doctoral repertoire in behavior analysis.
On his web page, Baer listed his current research interests as: "use of pre-school classroom settings for the modification of problem behavior in young children; program design for the extensive modification of deviant behavior in deviant children; environmental control of language development; motor and verbal imitation; behavioral analyses of retardation; stimulus control, and generalization of the effects of behavior modification."