Consistent with calls for a dynamical social psychology (Jacoby et al., 1987; Nowak, Lewenstein, & Vallacher, 1994), attitude formation was studied using a recently developed, computer-based simulation technique termed Higher Order Cognitive Tracing (see Jacoby et al., 1994). Participants’ attitudes toward 12 different products in 3 product categories were investigated as a function of incremental information input. As opposed to traditional memory-based models of attitude formation, the study explored online processing models. Results indicate that the impact of information tends to decrease the later in the sequence that information is accessed. In addition, new information that is affectively inconsistent with prior information tends to have a greater impact on attitudes than information that is affectively redundant. This effect is more pronounced earlier rather than later in the sequence of information acquisition. Implications and suggestions for future research are discussed.