Encoding modality and spatial memory retrieval.

This study examined the temporal characteristics of event-related brain electrical activity associated with the processing of spatial memories derived from linguistic and tactile information. Participants learned a map by (1) reading a text description of the map, (2) touching a wooden topological representation of the map (hidden from view), or (3) both. Subsequently, the participants' ability to use their spatial knowledge was tested in a spatial orientation task. Differential patterns of brain activity as a function of encoding modality were found at the very early (preconscious) stages of processing. In contrast, an analysis of behavioral performance revealed no differences between the encoding groups. A model of spatial memory retrieval is presented to account for the findings.