Memory for two types of spatial location: effects of instructions, age, and format

Three experiments, with old persons (59-80 years) and college students (17-30 years) in Experiments 1 and 2 and with college students (17-24 years) in Experiment 3, investigated the differences between two types of spatial location memory: memory for the location of individual items in an array and memory for occupied, as opposed to unoccupied, locations in an array. Young persons performed better than old persons on both measures of location memory. However, an effect of instructions (intentional vs. incidental for spatial location) was consistently obtained for memory for occupied, as opposed to unoccupied, locations, whereas no effect of instructions was obtained for memory for individual item locations. In addition, item location memory was superior for objects as opposed to matched words (Experiment 2), whereas occupied location memory was not affected by presentation format (Experiments 2 and 3). These differences indicate that spatial memory is a complex process whose properties are affected by variations in stimulus characteristics and task demands. It was concluded that the distinction of Hasher and Zacks (1979) between automatic and effortful processes is not adequate for understanding spatial memory. A recognition of the complex nature of spatial processing suggests a resolution of discrepancies in the literature based upon differences in stimulus characteristics, task demands, and the effectiveness of task-appropriate mnemonic strategies.