“…Because of these difficulties, a number of authors have considered more sophisticated ways of expressing individual differences within models of cognitive processes (e.g., Lee & Webb, in press;Peruggia, Van Zandt, & Chen, 2002;Rouder, Sun, Speckman, Lu, & Zhou, 2003;Steyvers, Tenenbaum, Wagenmakers, & Blum, 2003;Webb & Lee, 2004). The central innovation is to provide an explicit model for the kinds of individual differences that might appear in the data, in much the same way as established methods in psychometric models like Item Response Theory (e.g., Hoskens & de Boeck, 2001;Junker & Sijtsma, 2001;Lord, 1980).…”