Are the original Roelofs effect and the induced Roelofs effect caused by the same shift in straight ahead?

We investigated whether the original Roelofs effect and the induced Roelofs effect are caused by the same shift in perceived straight ahead. Subjects were presented with a target within a frame in complete darkness. Target and frame could both be shifted to the left or right of objective straight ahead. On separate trials, subjects gave verbal estimates about the position of either the target or the frame. The eccentricity of the frame was underestimated (the original Roelofs effect). However, the perceived position of the target did not follow this misjudgement of the eccentricity of the frame (the induced Roelofs effect was not present). Thus, it is unlikely that both effects have a common origin in misjudging egocentric straight ahead. Copyright 2002 Elsevier Science Ltd.