We examined how positive and negative reinforcement influenced time allocation, occurrence of problem behavior, and completion of parent instructions during a concurrent choice assessment with 2 preschool-aged children who displayed severe problem behavior in their homes. The children were given a series of concurrent choice options that varied availability of parent attention, access to preferred toys, and presentation of parent instructions. The results showed that both children consistently allocated their time to choice areas that included parent attention when no instructions were presented. When parent attention choice areas included the presentation of instructions, the children displayed differential patterns of behavior that appeared to be influenced by the presence or absence of preferred toys. The results extended previous applications of reinforcer assessment procedures by analyzing the relative influence of both positive and negative reinforcement within a concurrent-operants paradigm.DESCRIPTORS: choice making, preschool children, problem behaviorA number of applied investigations have evaluated the variables that influence choice with the goal of achieving better clinical outcomes in the reduction of problematic behavior (Fisher & Mazur, 1997). These studies have used a concurrent-operants arrangement in which two or more behaviors are concurrently available and each is correlated with an independent schedule of reinforcement. For example, investigators have examined various reinforcement dimensions (e.g., reinforcement rate, delay, and quality) to determine whether they have similar efThis research was supported by Grant R01-HD 29402 from the National Institutes of Child Health and Human Development of the National Institutes of Health. The opinions expressed herein do not necessarily reflect the position or policy of that agency. The authors express their appreciation to the families who participated in this study. We also express our appreciation to Agnes DeRaad, Barbara Rankin, and Anjali Barretto for manuscript preparation.Jennifer Asmus is now at the University of Florida. Address correspondence and requests for reprints to Jay Harding, University Hospital School, Room 251, 100 Hawkins Drive, The University of Iowa, Iowa City, Iowa 52242. fects in natural settings (e.g., Mace, Neef, Shade, & Mauro, 1994;Neef, Mace, & Shade, 1993;Neef, Shade, & Miller, 1994). As discussed by Neef et al. (1994), response alternatives in natural contexts are often asymmetrical across reinforcer dimensions. For example, an investigation by Neef et al. (1993) with students diagnosed as seriously emotionally disturbed showed that delays to reinforcement produced a bias toward the response alternative (choice) that provided more immediate access to reinforcement. A subsequent study by Neef et al. (1994) evaluated how specified reinforcer dimensions combined to influence the time allocated to two concurrent sets of math problems for youths with learning and behavior difficulties. The results showed that student resp...