Muller Lyer Final Lab Report
The nature of visual illusions is hotly debated in the scientific literature, in search of a theory to explain how perceptual distortions arise upon daily interactions with the world. The present study provides the first direct test of Day’s (1989) Conflicting Cues theory to account for the Muller-Lyer illusion. Perceptual compromise was investigated, by measuring the impact of global and local processing on perceptions of size, as modulated by Navon stimuli. Following exposure to global, local or neutral cues, participants adjusted the length of a line to match the length of an illusory stimulus, in a series of varying trials. However, the error rate for global and local groups did not significantly differ from the baseline condition, thus failing to support Day’s (1989) theory, and casting doubt on the usefulness of Navon stimuli in the current context. Methodological flaws and directions for future research are discussed, reaching the conclusion that multiple theories may be necessary to account for the different perceptual mechanisms responsible for the Muller-Lyer illusion.
The impact of global and local processing on the perceived adjustment error in the Muller-Lyer illusion. A test of Day’s (1989) Conflicting Cues Theory.
Identifying the mechanisms responsible for visual illusions, facilitates comparisons of perceptual accuracy and inaccuracy, and thus helps to inform an understanding of the way in which environmental stimuli come to be represented in the human psyche (Woloszyn, 2010). In the pursuit of such knowledge, controversy continues to reign regarding the Muller- Lyer Illusion. Despite the equal length of the left and right line in Figure 1, confluxion describes the overestimation of the right line due to the