Further support for the "drift" model of pigeons' short-term memory for spatial location

The Drift Model is a conception of animals' short-term memory process as manifested in tasks such as delayed matching to sample. The model has four main assumptions. First, an attention focus or pointer moves through memory space representing the information that must be remembered. Second, during sample presentation, the pointer migrates in the direction of memory space representing the sample. Third, during delays (i.e., retention intervals), the pointer drifts in a random walk manner through memory space. Fourth, during the choice phase, subjects choose the alternative in memory space closest to the pointer. The model successfully accounts for many aspects of rats' (Roitblat & Harley, 1988) and pigeons' (Wilkie & Kennedy, 1987) short-term memory for spatial location. In the present research two explicit predictions were derived from the model, tested using pigeons in a delayed matching of key location task, and confirmed.