Perceptual Illusions Experiment: Muller-Lyer Illusion

Participants are asked to choose which lines of each trial are longer. Participants must complete each trial in a few seconds to make hallucinations effective. According to CogLab, 32 participants in our class completed the experiment and there were 3,201 participants in the global data. When a constant stimulation method was used, the length of the line with the outer wing remained the same length at 100 pixels in the experiment. The length of a wingless line is from 86 pixels to 134 pixels.

Muelleria illusion is one of the well-known illusion. It provides evidence that past knowledge and experience can influence our perception. In the Mueller-Lier illusion shown in Figure 3, two vertical lines including fins are shown. The left vertical line is facing inside and the right line is vertical. The fins are facing outward. Even with the same length, the line on the right appears to be slightly longer than the line on the left. Even if you recognize that the lines are the same, this effect still exists. For incorrect information input to the vision system, we believe that we do not perceive lines exactly. Gregory (1966) suggests that visual system inaccuracies are caused by dimensional stability changes. "Constant size is the ability to accurately determine the size of an object, its distance changes, but the size of its retinal image changes" (Ungerleider, Ganz & Pribram, 1976)

The illusion of Muelleriai and Ponzo can be explained using bypass rules and physiological mechanisms. Muller-lyer illusion is caused by the scaling of dimension consistency and the perception of depth. He thinks this is a way to interpret two dimensional data that causes hallucinations. The floor and ceiling are perpendicular at the inside of the room. The arrow inside the line CD can be thought of as the outside corner of the building. The size of the retina of images AB and CD will be the same, but our brain uses AB size in consistency to expand AB, so it looks longer than CD. Ponzo illusion with mask depends on similar effect

Gregory & Wallace (1963) examined a man named S. B. after undergoing orthodontic surgery to undo early blindness. A visual illusion such as Muller-Lyer, Ponzo Illusion, Poggendorf Fantasy, etc. is used to measure his visual perception. Special black-and-white graphic illusion is called illusion of face and fan, it is displayed in S. B. The result shows that he can record only the images of the fans he remembered from the touch. Even if he pointed him to him over and over he could not see the background. The authors conclude that S. B is still familiar with new eyesight and that S. B can not distinguish between letters because there is not enough visual cognitive learning and experience to do so. This shows that learning and experience play an important role in perception.