Assessment of Human Spatial Blocking With Stable and Unstable Landmarks

The purpose of the current experiment was to determine whether cue competition (e.g., blocking) occurs in the spatial domain with human participants in a desktop virtual environment. Beigler and Morris (1999) found that spatial blocking occurred in rats when trained to find a hidden goal relative to a stable landmark array. The present study investigated blocking of stable landmarks, which maintained a fixed spatial relationship to the goal location, in the presence of unstable landmarks, the location of which varied with respect to the goal location across trials. In Phase 0 (P0), participants were trained to find a goal in the presence of an array of directionally ambiguous landmarks (L0s). In Phase 1 (P1), a stable disambiguating landmark (L1) was added to the array. In Phase 2 (P2), a second stable landmark (L2) and several unstable landmarks (Ms) were introduced. All landmarks were the same shape, but had unique visual color patterns. On test trials, which were randomly interspersed amongst P2 trials, different combinations of landmarks were presented to determine the extent to which they controlled search. Search area in the presence of L2 and absence of L1 assessed blocking. Results and theoretical implications will be discussed.