Illusion Decrement and Transfer of Illusion Decrement in Müller-Lyer Figures

Abstract

In the work reported in the literature the reduction or decrement in the magnitude of the Müller-Lyer illusion with continued inspection has been typically investigated with the use of the composite illusion form. Three experiments are reported in which the illusion decrement was separately examined in the underestimated (wings-in) and the overestimated (wings-out) forms of the Müller-Lyer illusion, with particular attention paid to the transfer of illusion decrement between the two forms. Decrement occurred in both forms of the Müller-Lyer illusion, although there was considerable intersubject variability in decrement effects, and nonuniform rates of decrement across the inspection period. In none of the experiments did transfer of illusion decrement between the two forms occur. It is argued that the attentional/differentiation hypothesis of illusion decrement provides a plausible account of the present findings as well as of those found with the composite Müller-Lyer figure.

Decrement of the Müller-Lyer and Poggendorff illusions: the effects of inspection and practice

“…Obviously, the measurement-task hypothesis is invalidated if with this method decrement is found with the continuous-but not the intermittent-inspection procedure. The wings-in M-L illusion was not investigated since studies have either measured a small decrement effect (Predebon, Stevens, & Petocz, 1993), no decrement (Porac, 1994) or a puzzling pattern of illusion increment (increase) in the initial trials followed by illusion decrement in the later trials (Sarris, 1984).…”

“…It has been suggested (e.g., Predebon et al, 1993;Predebon, 1998; see also Lewis, 1908) that attentional set may promote the occurrence of illusion decrement, independently of other decrement-inducing factors. In particular, it seems plausible to assume that, at least in certain situations, observers learn during the course of a decrement session to switch from a 'whole' to a 'part-isolating' attitude (Predebon et al, 1993; see also Lewis, 1908). The continuous-inspection paradigm, by requiring observers to scan the test component (i.e., the M-L shaft or the oblique lines of the Poggendorff figure), is likely to facilitate a 'part-isolating' attitude and hence illusion decrement.…”

Der Einfluss geometrisch-optischer Täuschungen auf sakkadische Augenbewegungen

“…integrierende neuronale Netze des Hirnstamms[1]) und die adaptive Modifikation (Vermis[14] bzw. Flokkulus[24] des Zerebellums) der Puls-und Step-Komponente jeweils in verschiedenen zerebralen Strukturen erfolgt, sind sowohl unterschiedliche retinotopische und extraretinotopische Einflüsse als auch von der Orientierung der Müller-Lyer-Figuren abhängige Einflüsse auf die postsakkadische Drift möglich.Eine Adaptation der wahrgenommenen Längenunterschiede tritt in den ersten 1 -2 Minuten einer kontinuierlichen Inspektion von Müller-Lyer-Figuren auf[16]. Eine adaptive Anpassung der Sakkadenamplitude wird dann ausgelöst, wenn bei aufeinander folgenden Sakkaden die Endposition des Auges systematisch vom Sakkadenziel abweicht[21].…”