| Abstract: This study examined the use of demand functions to describe differences between behavior reinforced by food and behavior reinforced by attention in children with autism. Several previous studies have identified systematic scalar differences in reinforcer value across different classes. This study attempts to extend those findings by examining differences in essential value (or, how the behavior reinforced by food and attention changes as the price of those commodities increases). Preferred food items and forms of attention were identified using paired-stimulus preference assessments. Next, those stimuli were delivered using fixed-ratio schedules. Response-requirements on the ratio schedules were manipulated across sessions in an increasing and decreasing sequence. Results show systematic changes in reinforcers earned (consumption) and response-rate as a function of ratio-requirement. Moreover, the procedures detect differences in how consumption of the commodities are sensitive to price and the resulting data are well described by Hursh and Silberberg's (2008) exponential demand function. |