Quantifying persuasion effects on choice with the decision threshold of the stochastic choice model

Three studies tested the stochastic difference choice model (proportional difference, PD, version in González-Vallejo, 2002) in the domain of decision making under certainty. Consumer services and products, hotels defined by price and quality and MP3 players defined by price and memory size, served as choice pairs. The ordinal prediction relating the proportional difference variable, d (computed from stimuli pairs), and the observed choice proportions was supported. Model fitting showed that PD’s estimated decision threshold measured within-person sensitivity to value attribute differences both at baseline and after persuasion manipulations. The threshold was also related to whether individuals were low or high in Need for Cognition (NFC, Cacioppo & Petty, 1982). Cross-validation strategies also showed PD to be descriptive and robust.