Comparison of verbal preference assessments in the presence and absence of the actual stimuli.

Stimulus preference assessments for individuals with developmental disabilities typically involve offering choices among stimuli and providing immediate access to the chosen stimuli. Several researchers have explored the utility of presenting choices verbally, thereby obviating the need to present the choices in tangible form and deliver access to those choices immediately. However, studies that have compared verbal selection to selection among tangible stimuli have nonetheless delivered the chosen stimulus following selections, in essence, manipulating the antecedent but not the consequence. It therefore remains unclear whether preference assessments that do and do not include the actual stimuli yield comparable results. The current study compared preference assessment results for three participants in which either (a) the stimuli were presented, selections were made verbally, and selection resulted in no differential consequence, or (b) the stimuli were presented both verbally and in tangible form, and selection produced access to the stimulus. Reinforcer assessments were then conducted to test contradictory predictions of reinforcer efficacy made by the two methods. Comparisons between the two assessments yielded only modest rank-order correlations (M=0.24; range, -0.17 to 0.57) that varied widely across participants. Results of the reinforcer assessments suggested that the verbal-plus-tangible stimulus preference assessment more accurately predicted reinforcer strength.