The Impact of the Landmark Attraction Effect and Central Tendency Bias on Spatial Memory Distortions

The successful communication of spatial information with maps allows correct spatial memory retrieval. Space-referencing map elements like grid pattern lead to a higher spatial accuracy in memory performance. We studied the influence of the landmark attraction effect and the central tendency bias predicted by the categorical adjustment model. While landmark attraction effect would lead to an attraction toward the landmark for the recalled object location, central tendency bias would lead to a deviation toward the center of a given field. The effects of these distortions were investigated on two different kinds of grid pattern, continuous grid lines and grid crosses, superimposed on a map or on a blank background. Results showed higher object-location memory accuracy for grid crosses. As expected, a clear central tendency bias was observed for the continuous grid lines according to the expected central tendency bias. However, there was no clear landmark attraction effect or central tendency bias for the grid crosses. We suspect a partial cancellation of the two opposing effects in this case. Overall results, central tendency bias seems to be stronger than the landmark attraction effect. In our experimental design, the landmark attraction effect seems not to be able to eliminate the central tendency bias, but to mitigate its strength. We suggest a correcting influence of map elements on object-location memory as the spatial distortions caused by the central tendency bias of the complete grid are significantly reduced in the grid cross condition. Future studies have to show more exactly how different shifting effects of recalled object positions can be used cartographically to reduce distortions of the mental representation of space.