Preference and Reinforcer Identification

Overview

Positive reinforcement is a technical term for a condition in which a target response increases because a preferred stimulus, such as a favorite toy, has been presented following that response. It is similar to the less technical term reward; however, rewards do not always increase behavior, whereas positive reinforcers, by definition, do. Positive reinforcement–based procedures are a commonly used component of many behavior modification programs, particularly those used to teach skills to students with developmental disabilities. One important aspect of reinforcementbased procedures is the provision of a preferred stimulus after the targeted response occurs. Thus, it is important that the stimulus being presented is one that the individual prefers.

Despite the importance of using items that are highly preferred, it is often difficult to identify preferred and effective reinforcers for students with developmental disabilities. The identification of reinforcing stimuli for individuals with developmental disabilities may be problematic for a variety of reasons. Some students may possess limited verbal skills, affecting their ability to indicate preferences through typical methods such as speech. A second factor that sometimes interferes with identifying preferred reinforcers is that preferences are often highly idiosyncratic in nature. For example, a toy car might be an effective reinforcer for one student, whereas a piece of discarded string might be effective for another (e.g., a student with autism). Third, even though caregivers may know the student quite well, research has suggested that caregivers are often inaccurate in identifying stimuli that function as effective reinforcers. Finally, many students with developmental disabilities display maladaptive behaviors, such as physical aggression, or may have multiple impairments that may limit their exposure to naturally occurring reinforcing events. As a result, these students may show relatively few preferences for stimuli or activities.

In the absence of techniques to identify preferred reinforcers, researchers and practitioners may rely on arbitrarily chosen items, which may or may not function as effective reinforcers. Over the past two decades, a variety of assessments have been developed to identify stimuli that are highly preferred and function as effective reinforcers for students with developmental disabilities. The purpose of this entry is to provide the reader with an overview of several basic assessment techniques that have been shown to effectively identify positive reinforcers. In addition, we discuss various factors that may influence the effectiveness of reinforcers during reinforcementbased programs.

Preference Assessments: Research Basis and Application

The term preference assessment refers to a variety of procedures that are designed to (a) identify preferred stimuli (items or activities) that may function as effective reinforcers and (b) rank-order those stimuli in terms of the student's preferences. By contrast, a reinforcer assessment is an evaluation to determine whether delivery of one or more preferred stimuli following a particular response actually increases the probability of that response (i.e., it determines whether the preferred stimuli actually function as reinforcers). In the published literature, the majority of preference assessment studies have also included a reinforcer assessment to validate the outcome of the preference assessment. The reinforcer assessments have generally shown that stimuli identified as highly preferred are more effective reinforcers than those that are less preferred. Four methods have been reported in the existing literature for effectively identifying preferred stimuli that also function as effective reinforcers. In general, all preference assessments share some common characteristics. First, an array of potential items is identified either through caregiver report [Page 1442]or by direct observation of the student interacting with various stimuli. Most preference assessments employ stimulus arrays ranging from 6 to 16 items. Once the array of items is identified, the formal assessment process occurs. Although preference assessment methods may vary in the manner that stimuli are presented, in general, all preference assessments involve measurement of the student “interacting with” the available stimuli. Such interactions may include reaching for an item, touching an item, visual or physical orientation toward the items, or interacting with the items in the manner for which they were intended (e.g., listening to music on headphones). Finally, all preference assessments involve a relative ranking of the items from most to least preferred.

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