Standard demand theory assumes perfectly informed consumers with constant tastes
and preferences (Chang and Kinnucan 1991). In today’s grocery retail environment, where consumers possess less-than-perfect information, food choice behavior and demand are strongly affected by changes in levels of available information (Grewal and Levy 2007). Given the level of attention devoted to health-based and dietary knowledge, preferences may change with seasonal demand patterns and change over time as new or better infor- mation becomes available. Relaxing the assumption of constant consumer preferences, the AIDS model in Equations (3) and (4) can be extended to incorporate elements of dynamic consumer behavior by allowing selected parameters to vary in order to represent changes in information constraints with exogenous variables (Rickertsen 1998). Verbeke and Ward (2001) suggest extending the AIDS model to account for seasonal shifts Si rep- resented by monthly shift variables. Dynamic consumer behavior is incorporated through a time trend T. The constants αi in Equation (3) are then modified to