Relative Versus Absolute Reinforcement Effects: Implications for Preference Assessments

Abstract

We compared results obtained in two previous studies on reinforcer identification (Fisher et al., 1992; Pace, Ivancic, Edwards, Iwata, & Page, 1985) by combining methodologies from both studies. Eight individuals with mental retardation participated. During Phase 1, two preference assessments were conducted, one in which stimuli were presented singly (SS method) and one in which stimuli were presented in pairs (PS method). Based on these results, two types of stimuli were identified for each participant: High-preference (HP) stimuli were those selected on 75% or more trials during both preference assessments; low-preference (LP) stimuli were those selected on 100% of the SS trials but on 25% or fewer of the PS trials. During Phase 2, the reinforcing effects of HP and LP stimuli were evaluated in reversal designs under two test conditions: concurrent and single schedules of continuous reinforcement. Two response options were available under the concurrent-schedule condition: One response produced access to the HP stimulus; the other produced access to the LP stimulus. Only one response option was available under the single-schedule condition, and that response produced access only to the LP stimulus. Results indicated that 7 of the 8 participants consistently showed preference for the HP stimulus under the concurrent schedule. However, when only the LP stimulus was available during the single-schedule condition, response rates for 6 of the 7 participants were as high as those observed for the HP stimulus during the concurrent-schedule condition (1 participant showed no reinforcement effect). These results indicate that, although the concurrent-schedule procedure is well suited to the assessment of relative reinforcement effects (preference for one reinforcer over another), absolute reinforcement effects associated with a given stimulus may be best examined under single-schedule conditions.

Examination of Relative Reinforcement Effects of Stimuli Identified Through Pretreatment and Daily Brief Preference Assessments

“…Although our data suggest that caregivers may not be using the most preferred item when they repeatedly and exclusively deliver the highest ranked item identified during a pretreatment assessment, it is unclear that identifying and using temporarily more preferred items on a regular basis would produce clinically meaningful improvements under typical training conditions. For example, Roscoe, Iwata, and Kahng (1999) demonstrated that, although a greater proportion of responses were allocated towards higher preference items than lower preference items during concurrent-operant tasks, the higher preference item rarely produced higher absolute response rates during single-operant tasks. Similar results may apply to items identified during pretreatment assessments versus daily preference assessments, in that top-ranked items may produce indistinguishable absolute response rates regardless of when they were identified as most preferred.…”

Establishment of Mands Following Tact Training as a Function of Reinforcer Strength

“…We examined that possibility in the present study by teaching individuals to tact objects for which preference had been established previously through formal assessment. Results of a number of studies on the assessment of preference have shown that, when a preferred and a nonpreferred item are available in a free-operant concurrent arrangement, participants allocate responses toward the preferred item (Fisher et al, 1992;Roscoe, Iwata, & Kahng, 1999). Thus, we taught participants to tact preferred and nonpreferred items and predicted that, if mands emerged, they would favor the preferred items.…”

Effects of Stimulus Variation on the Reinforcing Capability of Nonpreferred Stimuli

“…First, the two general patterns of responding (preference for HQ during the HQ vs. VLQ condition; switching during the HQ vs. VSLQ condition) were not observed for every participant (see Josh and Matt), and it is likely that these patterns were influenced by either the specific stimuli or the number of stimuli included in the initial preference assessments. In other words, although it seemed reasonable to define preference (HQ, SLQ, LQ) based on rankings, a given ranking may not be predictive of a reinforcement effect (Roscoe, Iwata, & Kahng, 1999). Depending on which and how many stimuli are included in a preference assessment, it is possible that few stimuli, all stimuli, or all stimuli above a given rank would function as reinforcers.…”

“…A singlestimulus preference assessment (Pace et al, 1985) was conducted to identify nonpreferred (NP) stimuli. The rationale for using this assessment was that stimuli not selected in a paired-stimulus format may nevertheless function adequately as reinforcers (Roscoe et al, 1999); as a result, we felt that nonapproach to a stimulus presented singly would yield more valid information about lack of preference. Each participant was allowed to sample each item prior to the start of the assessment.…”