Muller Lyer Theory

Visual illusions have been studied among psychologists for many decades. “Oppel is frequently cited for coining the term ‘geometrical optical illusions’ in 1855” (Phillips, Wade 2014). Early studies have contributed to the development in later psychologist’s interest in why and how illusions affect us. This eventually advanced into Gestalt psychology, with leading psychologists such as Wertheimer (1912) believing “visual perceptions cannot be understood simply by analysing the scene into its elements. Instead what we see depends on the relations of these elements to another”. Werthemier’s belief could be applied to the Muller Lyer illusion. This illusion was originally published by its namesake Muller-Lyer, F.C. (1889), which has gone …show more content…
One being by Holding (1970) * who believed visual averaging – in which an individual looks at the ends of an object and judges that, rather than the actual length of what should be judged (the shaft) therefore makes a visual error-, which was recognised by Pressey, Martin (1990). Holding’s proposal of visual averaging has become one that many researchers have looked into and have produced their own findings. For example, Matziridi, Brenner and Smeet (2013) found that even when the stimulus was flashed in front of participants instead of presented for a given amount of time “mislocalisation [was] related to the eye position at the end of the saccade, rather than to the position of the saccade target within the image”. Which meant that when participants observed the Muller-Lyer illusion in flashes, they only looked at the middle space between the fins (when concaved) but looked at the entire shaft when the fins were convex.

Explanations of the Muller-Lyer illusion came hand-in-hand with variations of this study being produced. Earlebacher, Albert, Northwestern U Sekuler, Robert (1969) opted to change the angle of the fins in each condition to see if that affected an individual’s perception, however results showed that the greater the distance the fin from the shaft, the decrease in the illusion’s …show more content…
As of yet there hasn’t been a definitive explanation as to why our eyes are deceived by this illusion. However, research has shown that this illusion can affect ‘distance judgments and decision-making’ in everyday life (Gillan, Schmidt and Hanowski, 1999). Their research found that when map reading individuals that observed roads with ‘outward-going wings led to higher distance estimates than did inward-going wings’ (Gillan et al). Additionally, research into the Muler-Lyer illusion has provided benefits to research in mental health. Recent evidence suggests that “susceptibility of Schizophrenics to the Muller-Lyer illusion may be a marker of vulnerability, detectable in prodromic patients” (Pessoa VF, Monge-Fuentes V, Simon CY, Suganuma E and Tavares MC, 2008). Therefore, the Muller-Lyer illusion amongst other tools are being used to detect if an individual is showing early signs of