Muller-lyer Illusion.
The way the eye and the mind judge or perceive things can sometimes result in recurring errors. A good experiment to detect these discrepancies is by conducting the Muller-lyer Illusion test. Conducting an optical illusion like Muller-Lyer illusion, we can understand how a human mind and conscious mechanism works. Various explanations for this include the refraction of light on a surface. How a human eye and the entire visual processing system is built could also lead to optical illusions. German sociologist Franz Carl Muller-Lyer created and published more about the illusion in 1889, and various theories have been brought up to explain the phenomenon. According to the illusion, two lines of the same length are drawn on a surface seem to be of different lengths when arrowheads that extend inward and outward are added at the end of each line.
What explains the occurrence of Muller-Lyer Illusion?
Various arguments by scholars have been brought forward to explain the occurrence of the Muller-Lyer illusion. According to Richard Gregory, a psychologist, Muller-Lyer illusion occurs due to miscalculation during size constancy scaling. Size constancy is the act where people view the size of an object as being constant in regards to the distance between an object and a person. Gregory states that the arrowheads are placed at the end of linework up the visual processes that define the length of images seen with the eye. As a result, lines with arrowheads pointing outward seem longer. However, this argument’s efficiency has been discredited with others stating that Gregory’s idea is only applicable in 3D and may result in errors when applied in two-dimensional conditions.
The depth cue can also be used to explain how Muller- Lyer illusion occurs. According to this explanation, depth plays a critical role in an individual’s ability to approximate distance. This means that an individual can approximate the lengths of the two lines with arrowheads at the end as a result of depth cues visible on these lines. Angles on the arrowhead greatly affect how an individual views the length of a line. The line with arrowheads pointing away from the line seem to have a broader angle that can be viewed to be slanting. This results in an individual to perceive the line to be far away, thus looking shorter. The line with arrowheads pointing towards the line can be perceived as having narrow angles to an individual thus longer than the other line. Removal of the arrowheads on the line can be used to identify the illusion caused by the inclusion of the arrowheads on the lines.
Another explanation for this is given by R.H. Day, who stated that Muller-lyer illusion happens as a result of conflicting cues. His argument stated that an individual’s ability to approximate the length of a line depends on the length of the drawn line and the entire figure’s length. Day adds that the illusion occurs due to varying stimuli, which are the arrowheads on top of a drawn line. The arrowheads significantly impact the perception of the length of a line to either being longer or shorter. A compromise has to occur when approximating the lengths of the two lines resulting in viewing one line to be longer than another. Because the length of the entire figure is more than the lines, an individual can view the line with arrowheads facing outwards to seem longer.
Experiment: Performing the Muller- lyer illusion.
The goal of conducting the experiment.
The goal of conducting this experiment is to identify and understand the effects of illusion on an individual’s mental and decision making processes. Besides that, we shall also identify the stimulus that triggers illusions in people during such an experiment.
Requirements for the experiment.
Muller-lyer illusion is a simple visual illusion experiment that does not require a lot of materials to conduct the experiment. A blank writing surface will be used to draw various figures that will be used during the experiment. Two pens that contain two different bright colors will be used to draw diagrams in which the subjects will compare their lengths. The use of different colorful colored pens will make it easier for the subjects to easily differentiate various diagrams to avoid confusing subjects that will participate in the experiment. Last but not least, subjects of all ages and sex will also be utilized to identify the drawn lines’ lengths.
Variables that may affect the results from the experiments.
While conducting a Muller-lyer illusion experiment, factors such as age and time played a critical role in influencing an individual’s accuracy in identifying diagrams that were longer or shorter. Younger subjects displayed a higher margin when they were determining a longer line compared to older subjects. Older subjects were more accurate when they identified a long line since they were more experienced when it came to approximation. I also recognized that the longer an individual took to identify which the two lines are longer, the higher the chances of identifying which line is longer. This allows the brain to approximate accurately the length of lines drawn. To get varying results, subjects were exposed to different time periods to measure their efficiency and speed in identifying the length of these lines.
The Experiment.
Two pairs of parallel lines, each with a different color was drawn on a surface. All of the lines were either of equal length or their lengths differed slightly. On the first pair, we drew an arrowhead on the tip of the lines. The second pair we drew circles of the same size on the ends of the lines, as seen in the diagrams below. The use of different shapes at the end of different pairs of lines will help identify different types of stimuli that may affect an individual’s perception of the length of the lines. Once drawn, subjects were asked to identify a line that was longer than the other. Lines that have an arrow at the end were grouped together, while those with a circle were drawn on two separate surfaces.
Results of the experiment.
The majority of subjects above the age of 18 displayed a higher accuracy when asked to identify which among the two pairs of lines was the longest, the shortest, or the same length. However, this group of individuals understood the challenge posed and, as a result, took more time when asked to identify the difference in the length of the lines, a factor that increased their chances of responding to the challenge successfully. The majority of subjects had difficulty identifying which line among the pair with arrows is longer than a couple of lines that had circled on their end.
When younger subjects below the age of 18 were provided with more time than stipulated, many of the younger subjects managed to identify each line’s length accurately. When older subjects were exposed to the same conditions, the number of adults who correctly identified the lines’ length did not change drastically. However, when both older and younger subjects were given limited time, their accuracy levels dropped significantly. Lack or availability of enough time to identify the length of the lines greatly affected the response by the subjects.