The visual system commonly has to estimate the relative location of a
textured region but the stimulus features used to perform that task ar
e yet to be determined. The use of centroid, midpoint and peak activit
y cues would all be reasonable. In the current experiment an attempt w
as made to assess the relative efficacy of these three cues. The obser
vers were required to indicate whether a cloud of either 3, 10 or 100
elements was located to the left or right of an imaginary line formed
between two reference elements. Performance was compared to that expec
ted from the use of the three cues. It was concluded that the cue used
varied as the characteristics of the cloud changed and therefore that
the visual system is not restricted to the use of a single cue type w
hen localizing object clusters. Copyright (C) 1996 Elsevier Science Lt
d.