Research & Laboratories
Overview of Research Program
My research focuses on disorders of learning and behavior. Within that broad context, my students and I conduct studies on basic learning processes, assessment and treatment of severe problem behavior, staff and parent training, and research methodology. These areas define our general mission, around which most students develop coordinated and thematic studies. However, students are free to propose any type of research that can be accommodated by our resources and personnel. Some examples of recently completed projects are listed below.
Analysis of methods for establishing praise as a conditioned reinforcer (Claudia Dozier). Individuals who do not respond to praise as a reinforcer are dependent on edible reinforcers. This study involves an attempt to establish praise as a conditioned reinforcer.
Assessment and treatment of a foot fetish (Claudia Dozier). We conducted a functional analysis to identify stimuli that occasioned inappropriate sexual behavior exhibited by a man diagnosed with autism. We then evaluated the effects of several interventions (transfer of stimulus control, time out, sensory extinction, response interruption) and examined generalization to extra-therapy settings. 
Assessment of stimulus control during extinction (Pam Neidert). Some individuals continue to engage in behaviors after reinforcement for those behaviors has been withdrawn (i.e., problem behavior does not extinguish, or adaptive behavior does not decrease during a “reversal” condition). Maintenance during extinction has been attributed to several variables but none has been studied extensively. This study attempts to identify those features of the environment that may acquire stimulus control (e.g., presence of the reinforcer, instructions, therapist, and physical setting) and influence behavior during extinction.
Comparison of in-clinic and in-home functional analyses (Jessica Thomason). Some researchers have suggested that functional analyses conducted under clinic conditions may not reveal sources of reinforcement that maintain problem behavior in the natural environment. To address this question, we are comparing the results of independent assessments conducted in our outpatient clinic and in the home environment.
Assessment and treatment of elopement (Pam Neidert). Running away (elopement) is a disruptive behavior and can expose an individual to dangerous situations. This study attempts to identify the environmental determinants of elopement on an individual basis and to develop effective treatment procedures.
Evaluation of response latency as an index of problem behavior during functional analyses (Jessica Thomason, in collaboration with Eileen Roscoe at The New England Center for Children). Research on the assessment and treatment of problem behavior traditionally uses a measure of behavior based on its repeated occurrence (e.g., rate or duration). However, some problem behaviors may be so severe (serious SIB or aggression) or disruptive (running way) that they terminate a session. Therefore, it would be helpful to identify other dimensions of behavior that may be used when occurrences of the behavior are limited for one reason or another. This study evaluates latency to the first response as a measure of behavior during assessment.
Some anomalous findings from paired-stimulus preference assessments (Leah Koehler, in collaboration with Liming Zhou at Arlington Developmental Center). Results from paired-stimulus (PS) preference assessments are not always predictive of choices under concurrent schedule arrangements, which may be due to the limited number of pairings between any two stimuli during the PS assessment. We examined the predictive consistency of PS outcomes by conducting PS assessments and subsequently presenting the highest and lowest ranked stimuli on 50 paired trials. 
Observer training through exposure to increasingly complex video exercises (Carrie Dempsey). Observer training is a prerequisite to all behavioral assessment and intervention efforts. Although an 80%-90% performance criterion is considered acceptable in training, training conditions vary widely and often unsystematically. This study evaluates observer training based on systematic exposure to a series of videotapes depicting events of increasing complexity.
Influences of response rate and distribution on interobserver agreement scores (Natalie Rolider). This study compares four commonly used methods for calculating interobserver agreement and determines the influences of response rate (low, medium, high) and distribution (bursting, end-of interval responding) on agreement scores based on the different calculations.
Assessment of olfactory stimuli as reinforcers for individuals with Prader-Willi Syndrome (Sarah Bloom). Previous research has shown that individuals with disabilities select edible stimuli over leisure stimuli, but few researchers have included olfactory stimuli in their array and no one has directly assessed the reinforcing effects of olfactory stimuli. We conducted paired-stimulus preference assessments and included edible, leisure, and olfactory stimuli. Then we directly assessed the reinforcing effects of olfactory stimuli.
Computerized measurement of self-injury (David Wilson). Self-injurious behavior (SIB) is typically measured via direct observation of responding. However, injuries produced by SIB may be a useful corroborative measure or primary measure when responding is difficult to observe. We evaluated the utility of a computerized photographic technique for measuring tissue damage by first comparing it to a transparency-based technique in estimating the size of 20 wound models. We then determined the correspondence between changes in wound size and changes in the frequency of SIB during the treatment of a woman diagnosed with Prader-Willi Syndrome.
Elimination of position bias during preference assessment and discrimination training (in collaboration with Jason Bourett, New England Center for Children). Many tasks involve selecting an item from two or more available options. Most individuals select on the basis of cues presented by the trainer (e.g., “Point to the red one) or on the basis of preference for one item over another. Some individuals habitually make selections based on position (e.g., always selecting the item located to their left). This study evaluates methods for eliminating position bias during preference assessments and assesses generalization to other discrimination tasks.
Evaluation of a video-based preference assessment procedure (Pam Neidert). Typical preference assessments involve presentation of the actual stimuli of interest (food or leisure items), which may be difficult or time consuming for certain types of events (e.g., going to the movies). This study evaluates a preference assessment based on brief presentation of video clips depicting the activities of interest.
Effects of stimulus fading and enhanced consequences on the establishment of visual discriminations during PECS training (David Wilson). The Picture Exchange Communication System (PECS) is a popular method for teaching language to individuals with severe communication deficits, especially those diagnosed with autism. A critical stage in learning that causes many problems is the ability to discriminate one one stimulus from another. In this study we are comparing the benefits of antecedent vs. consequent manipulations during discrimination training.
Self-monitoring of stereotypic behavior (Jennifer Fritz). Results of several studies have suggested that teaching individuals with autism to record data on their stereotypic behavior results in decreases in the target response. However, the interventions included several components whose influence was not evaluated. This study separates the effects of instructions, reinforcement for self-recording, and reinforcement for the absence of stereotypy.Current Sources of Funding
Our research currently is funded through two mechanisms. One is the Florida Center on Self Injury, an extension of NIH-funded research that was established through Florida statute approximately 15 years ago. Self-injurious behavior (SIB) is a dramatic and serious disorder that takes a number of forms, the common feature of which is self-inflicted bodily damage. Designated as a clinical-research program, the center conducts studies on SIB, related behavior disorders, and behavioral replacement in individuals with developmental disabilities and autism and historically has operated at multiple sites in Gainesville. The second program is the UF-ARC Prader Willi Syndrome (PWS) program. PWS is a genetic disorder characterized by a number of clinical features, the most prominent being an apparent insatiable appetite leading to morbid obesity and associated health problems. Through the UF-ARC program, we provide clinical services to one of the largest PWS populations in the country (N=50+) and conduct studies on dietary management, exercise, self-injury, and other behavioral characteristics of the syndrome.
Laboratory Sites
We currently operate two lab sites in Gainesville. One is in a special education program located at the Sidney Lanier School; the other is both a day and residential program operated by the ARC.
Sidney Lanier Program. We operate one classroom as a research lab at a school for students diagnosed with developmental disabilities or autism. Students are recruited to participate in
studies on all aspects of performance (preference, behavioral acquisition, assessment and
treatment of problem behavior) or are referred by teachers. In the case of referral, we
attempt to design clinical studies around common problem behaviors.
ARC Program. We provide clinical services at the Alachua chapter of the ARC, which consist of program development, staff training, and individualized assessment and treatment.
We conduct research on these aspects of service in addition to other topics of a general
interest. One component of the ARC program is the PWS program, described above.
Recent Publications (last five years)
Iwata, B.A., Roscoe, E.M., Zarcone, J.R., & Richman, D.M. (2002). Environmental
determinants of self-injurious behavior. In S.R. Schroeder, M.L. Oster-Granite, & T.
Thompson (Eds.), Self-injurious behavior: Gene-brain-behavior relationships. (pp.
93-103). Washington, DC: American Psychological Association.
Kahng, S., Iwata, B.A., & Lewin, A.B. (2002). The impact of functional assessment on the
treatment of self-injurious behavior. In S.R. Schroeder, M.L. Oster-Granite, & T.
Thompson (Eds.), Self-injurious behavior: Gene-brain-behavior relationships. (pp.
119-131). Washington, DC: American Psychological Association.
Kahng, S., Iwata, B.A., & Lewin, A.B. (2002). Behavioral treatment of self-injury:
1964-2000. American Journal on Mental Retardation, 107, 212-221.
Worsdell, A.S., Iwata, B.A., & Wallace, M.D. (2002). Duration-based measures of
vocational task engagement. Journal of Applied Behavior Analysis,35, 287-290.
Zhou, L., Iwata, B.A., & Shore, B.A. (2002). Reinforcing efficacy of food on performance
during pre- and post-meal sessions. Journal of Applied Behavior Analysis, 35, 411-414.
Lindberg, J.S., Iwata, B.A., Roscoe, E.M., Worsdell, A.S., & Hanley, G.P. (2003). Treatment efficacy of noncontingent reinforcement during brief and extended application. Journal of Applied Behavior Analysis, 36, 1-19.
Neef, N.A., Nelles, D.E., Iwata, B.A., & Page, T J. (2003). An analysis of precurrent problem solving. Journal of Applied Behavior Analysis, 36, 21-33.
Hanley, G.P., Iwata, B.A., Lindberg, J.S., & Conners, J. (2003). Response-restriction analysis: I. Assessment of activity preferences. Journal of Applied Behavior Analysis, 36, 47-58.
Hanley, G.P., Iwata, B.A., Roscoe, E.M., Thompson, R.H., & Lindberg, J.A. (2003). Response-restriction analysis: II. Alteration of activity preferences. Journal of Applied Behavior Analysis, 36, 59-76.
Hanley, G.P., Iwata, B.A., & McCord, B.E. (2003). Functional analysis of problem behavior: A review. Journal of Applied Behavior Analysis, 36, 147-186.
Thompson, R.H., Iwata, B.A., Hanley, G.P., Dozier, C.L., & Samaha, A.L. (2003). Reversal effects under extinction, noncontingent reinforcement, and differential reinforcement of other behavior: A comparative analysis. Journal of Applied Behavior Analysis, 36, 221-238.
Roscoe, E.M., Iwata, B.A., & Rand, M.S. (2003). Effects of reinforcer consumption and magnitude on response rates during noncontingent reinforcement. Journal of Applied Behavior Analysis, 36, 525-539.
Iwata, B.A., & Worsdell, A.S. (2005). Implications of functional analysis methodology for the design of intervention programs. Exceptionality, 13, 25-34.
Neidert, P.L., Iwata, B.A., & Dozier, C.L. (2005). Treatment of multiply controlled problem behavior with variations of differential reinforcement. Exceptionality, 13, 45-53.
Thompson, R.H., & Iwata, B.A. (2005). A review of reinforcement-control procedures. Journal of Applied Behavior Analysis, 38, 257-278.
North, S.T., & Iwata, B.A. (2005). Motivational influences on performance maintained by food reinforcement. Journal of Applied Behavior Analysis, 38, 317-333.
McCord, B.E., Grosser, J.W., Iwata, B.A., & Powers, L.A. (2005). Analysis of response-blocking parameters in the prevention of pica. Journal of Applied Behavior Analysis, 38, 391-394.
Kahng, S., & Iwata, B.A. (2005). Noncontingent reinforcement: From basic research to therapeutic application. European Journal of Behavior Analysis, 6, 29-32.
Iwata, B.A., & Kahng, S. (2005). Some undesirable effects of noncontingent reinforcement. European Journal of Behavior Analysis, 6, 47-50.
Koehler, L.J., Iwata, B.A., Roscoe, E.M., Rolider, N.U., & O’Steen, L.E. (2005). Effects of stimulus variation on the reinforcing capability of nonpreferred stimuli. Journal of Applied Behavior Analysis, 38, 469-484.
Worsdell, A.S., Iwata, B.S., Dozier, C.L., Johnson, A.D., Neidert, P.L., & Thomason, J.L. (2005). Analysis of response repetition as an error-correction strategy during sight-word reading. Journal of Applied Behavior Analysis. 38, 511-527.
Wallace, M.D., Iwata, B.A., & Hanley, G.P. (2006). Establishment of mands following tact training as a function of reinforcer strength. Journal of Applied Behavior Analysis, 39, 25-34.
Hanley, G.P., Iwata, B.A., & Roscoe, E.M. (2006). Some determinants of changes in preference over time. Journal of Applied Behavior Analysis, 39, 189-202.
Iwata, B.A. (2006). On the distinction between positive and negative reinforcement. The Behavior Analyst, 29, 121-123.
Iwata, B.A., & Smith, R.G. (in press). Negative reinforcement. In J.O. Cooper, T..E. Heron, & W.E. Heward (Eds.), Applied behavior analysis. Columbus, OH: Merrill.
Thompson, R.H., & Iwata, B.A., (in press). A comparison of outcomes from descriptive and functional analyses of problem behavior. Journal of Applied Behavior Analysis.
Wallace, M.D., Iwata, B.A., Hanley, G.P., Thompson,, R.H., & Roscoe, E.M. (accepted for
publication). Further examination of schedule effects during treatment of elf-injurious
behavior with noncontingent reinforcement. Journal of Applied Behavior Analysis.
Rolider, N.U., Iwata, B.A., & Bullock, C.E. (accepted for publication). Influences of
response rate and distribution on the calculation of interobserver agreement scores.
Journal of Applied Behavior Analysis.
Dozier, C.L., Iwata, B.A., & Worsdell, A.S. (accepted for publication). Assessment and
treatment of a foot-shoe fetish displayed by a man diagnosed with autism. Journal of
Applied Behavior Analysis.
Wilson, D.M., Iwata, B.A., and Bloom, S.E. (accepted for publication). Evaluation of a
computer-assisted technique for measuring wound severity. Journal of Applied
Behavior Analysis.
Thomason, J.L., Iwata, B.A., Neidert, P.L., and Roscoe, E.M. (accepted for publication).
Evaluation of response latency as the index of problem behavior during functional
analyses. Journal of Applied Behavior Analysis.
Dempsey, C.M., Iwata, B.A., Fritz, J.N., & Rolider, N.U. (accepted for publication).
Observer training revisited: A comparison of in vivo and video instruction. Journal of
Applied Behavior Analysis.
