Comparing Judgments of Relative Direction and Object-Based Judgments as Measures of Human Spatial Memory: Evaluation with a Measurement Model.

Directional pointing tasks-particularly judgments of relative direction (JRDs)-have advanced research on spatial memory. However, overreliance on a single measurement task like JRDs may miss nuances in how spatial information is processed and represented. Therefore, we compare JRDs with object-based judgments (OBJs). While these measures seem to reflect different cognitive processes, a parameter-free measurement model suggests they assess the same underlying memory representations. This model, grounded in two key assumptions, allows point estimates of JRD absolute angular error to be calculated from specific OBJ responses. Across two experiments (N = 96), we found support for two conclusions: (a) JRDs and OBJs access the same memory representations, and (b) JRDs combine the absolute angular error from two different sources, while OBJs isolate a single source, making OBJs more specific.