Erratum

Perception, 1990, volume 19, pages 471–482 “An acceleration illusion caused by underestimation of stimulus velocity during pursuit eye movements: Aubert-Fleischl revisited” by Alexander H Wertheim and Peter Van Gelder Four lines have been missed out from the second paragraph on page 480 starting with line 14 from the top. This paragraph should read: Note that when eye velocity across the stimulus increases, both V ret and V Tef increase but their difference remains the same. However, the JND between them (and thus the threshold) increases in accordance with Weber's law. Consequently V p is reduced. This explains the reduction of perceived velocity during the execution of an eye movement (ie the acceleration illusion) and also the dependence of this reduction on the threshold for motion. The penultimate paragraph consisting of four lines starting with line 12 from the bottom: Note that this cannot happen when the background moves in the same direction as the eyes, because here retinal image velocity is smaller than eye velocity. A reduction in reference signal size then reduces the difference between V Kt and V ref , ie it reduces V p and therefore, if anything, enhances the acceleration illusion. Should be removed as it is a repeat of the paragraph above it. We apologise to the authors for this typesetting error.