Testing the precision of spatial memory representations using a change-detection task: effects of viewpoint change

The brain encodes spatial information in at least two distinct ways: egocentric representations encode locations relative to the observer, whereas allocentric representations encode locations relative to the environment. Both inform spatial memory, but the extent to which they influence behaviour varies depending on the task. In two preregistered experiments we used a psychophysical approach to measure the precision of spatial memory while varying ego- and allocentric task demands. Participants attempted to detect the changed location of one of four objects when seen from a new viewpoint. In both experiments (one using a Same/Different task, the other a 2AFC task), psychophysically-determined change detection thresholds showed a monotonic but non-linear increase as the degree of viewpoint change increased. Our findings were consistent with a preregistered model which shows how, governed by distinct ego- and allocentric contributions, the precision of spatial memory changes lawfully as a function of viewpoint shift.