Muller-lyer illusion

Illusion 2


The current experiment was based on the Muller-Lyer Illusion. There were 28 participants that were presented with two perpendicular lines that appeared on a screen. The line on the upper right of the screen had outward-drawn wings, and the line on the upper left had no wings. Participants were presented with a figure of several tests to place which perpendicular line was longer. There were two different set of consequences that were concluded. The first population of 27 participants from a schoolroom were presented. The 2nd consequences were found by one individual pupil from the first population of pupils. The consequences demonstrated that the 27 participants perceived an addition in semblance by the terminal of the experiment. The 2nd set of consequences from the individual pupil besides demonstrated an addition in semblance. Nevertheless, the pupil ‘s graph showed more of a scattered line by the terminal of the experiment. Overall, the consequences seem to back up the illusory consequence.

Illusion 3

Lab Report on Muller-Lyer Illusion

Several theories have been conducted to give account on why perpendicular lines seem longer than horizontal lines. In this experiment, the perceiver was seeking to mensurate the perceptual experience of the perpendicular lines. Second, the intent of this experiment was to measure a technique named the method of changeless stimulation. Since this experiment was peculiarly subjective, the effort was to associate features of our perceptual experiences to physical features. Many other experiments have been conducted to try to happen and explicate why some perpendicular lines may look longer than others. Avery & A ; R.H Day ( 1957 ) had a theoretical account proposing that the form of your ocular field is to keep responsible for the misconception of the length of a line. The Avery and R.H Day supported Kunnapas ‘ ( 1957 ) attack that since a ocular Fieldss horizontal image is longer than its perpendicular image, an person will see the horizontal line as being shorter than the perpendicular line. The consequences found by Avery et Al. ( 1958 ) suggested that the lengths between the two lines of an “ Fifty figure ” are explained by the orientation of the retinal image. It is expected to happen that the bisection of the line is critical to the semblance, and non some difference in judging perpendicular and horizontal lines. Girgus and Coren ( 1975 ) measured the sum of perspective convergence exposure affected when deepness cues were at manus. This experiment demonstrated that perspective convergence was identified in images with deepness cues, which resulted in the participant ‘s size grading mechanisms. In other words, the semblance of a image utilizing depth cues should go stronger when utilizing horizontal-vertical lines. Similarly to the Muller-Lyer Illusion, these surveies identified a perceptual attack, and besides considered other external variables that may hold a relation to the size stability of the two lines.

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Based on this present experiment, it can be hypothesized that our perceptual experience of size stability, form, and deepness cues interconnect with our semblances whether the perpendicular line are longer or shorter. In add-on, clip frame spent on a stimulation can be an effectual and of import factor upon our perceptual experiences of semblances. Last the line with the wings by and large seems to be longer, oppose to the line without wings.



Participants in this experiment consisted of 28 Cognitive Psychology pupils. The individual pupil perceiver in this survey was a 21 twelvemonth old female and a current BAHS Psychology pupil go toing Laurentian University through Georgian college. The perceiver ‘s engagement in this experiment was due to involvement of the subject and cognitive assignment. The experiment was completed independently, and in the topic ‘s place during tiffin hours. Prior of finishing the experiment, there was a brief drumhead written on the Coglab web site to inform the pupil some background and instructional information from the experiment being presented. The participant had no wellness concerns, and wore corrected-to-normal-vision erosion spectacless.


The topic conducted the experiment on a 2008 HP laptop and was logged onto Wadsworth Cog Lab 2.0 Online research lab where the Muller-Lyer Illusion could be identified. A window appeared that filled the full screen.

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The Z key was used to place if the perpendicular line on the left manus side seemed longer. The key was used to place if the perpendicular line on the right seemed longer.


There were a sum of 150 tests shown for each participant. For each test, there was no clip frame. If the participants were traveling excessively rapidly, the computing machine would inquire them to take their clip and give an accurate response of comparative line length. A black screen would look at the beginning of the experiment. Participants were asked to press the saloon key when they were ready to get down the test. Participants were asked to give 15 proceedingss of their clip to finish this experiment. At the terminal of the experiment, they were asked to salvage their informations to a set of a planetary information of the other participants. Then a new web page showed the category norms and the personal norm of the topic.


The consequences were calculated by Wadworth Cog Lab 2.0 Online Laboratory. In experiment 1, participant responses were averaged. In figure 1, the graph displays the statistics based on the 28 participants. The consequences show that as the size of the line without wings ( pels ) increased so did the proportion of line without wings ‘bigger ‘ . There was a important addition when the size of the line without wings ( pels ) was 100 and increase to 103 from 0.0392 to 0.0785 severally.

Illusion 6

When analyzing single consequences, the consequences differ from that of the category norm. When the size of the line without wings ( pels ) was 85 to 100 there was no addition or lessening in response to proportion of line without wings ‘bigger ‘ . Proportion of line without wings ‘bigger ‘ was non evident until the pel of the line was about 103. Figure 2 displays the consequences that were obtained by an single participant from the survey.

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It is besides interesting to observe that the addition was non gradual when compared to the norm of the 28 participants. From the consequences from both category norm and single norm does back up the Muller-Lyer Illusion hypothesis.


The major surveies that were conducted with the horizontal-vertical semblance and the Muller-Lyer semblance were established while analyzing the consequences of the 28 participants. These consequences do back up the Muller-Lyer semblance position when mensurating the sizes of the two perpendicular lines. The illusive consequence was much stronger for the category participants oppose to the single information. If there would hold no appeared to hold any sort of semblances, so the graphs would hold shown a line at about 0.5 for a line without wings length of 100 pels. Avery et Al. ( 1969 ) old research demonstrated on how the influence of semblance on evident size, deepness cues and size and form, these lines or images attributed to vertical-horizontal semblances, length judgements are made suitably to the ocular field. However, the consequences did support that the bisection of the line is of import and influential to the semblance.

This besides supported the perceivers claim that depending on the size, deepness cues, it did impact a “ stronger ” or “ weaker ” semblance for both conditions. The other variables, such as size stability, Kunnapas ( 1957 ) explained that same size stability, whether you are far off or closer, your ocular field is affected by the other object. In other words, as the experiment was repeated several times with the difference of short, medium and long perpendicular lines, this still did non make a false semblance to the perceiver ; it merely increased the semblance when the lines became smaller.

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Another variable such as comparative tallness indicated that the higher the images are being interpreted as being farther off, than the lower the images became. Previous research done by Ward, Porac, Coren, & A ; Girgus, J.S. ( 1977 ) ; explained how depth cues associated and elicited by semblance figures. They confirmed other variables refering the stability grading and misapplied semblance. In future research, surveies should be performed to make a greater opportunity of false semblance, such as in the Muller-Lyer Illusion, doing the top line non as obviously different so that the semblance does non look once more. This would increase the semblance consequence and may analyse another feature to seek and mensurate these different readings. In add-on, scientists and psychologists should put more accent on the external and internal conditions ; such as clip and topographic point, different factors lending to psychological upsets, situational factors, and many other conditions. Of these different semblances, in a natural environment, it would be interesting to see on whether there is a greater or weaker impact among our perceptual experience of the universe around us ; the things we observe, think, and perceive.

Specific surveies related to biological positions of perceptual experience and semblances could underway and assist us understand why we think and perceive ocular images the manner it is presented to us. Although some of these findings are different, the overall consequences support the thought that illusive consequence is visually evident when the lines are progressively presented to the perceiver.

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  • Avery, G.C & A ; Day, R.H. , ( 1969 ) ; Girgus, J.S. & A ; Coren, S, ( 1975 ) ; Finger, F.W & A ; Spelt, D.K, ( 1947 ) ;
  • Houk, R.L, Mefferd, R.B.Jr. & A ; Greenstein, ( 1972 ) . The influence of semblance on evident size, deepness cues and size and form, these lines or images attributed to vertical-horizontal semblances, length judgements are made comparative to the ocular field.
  • Finger, F.W. & A ; Spelt, D.K. ( 1947 ) .The illustration of the horizontal-vertical semblance. Journal of Experimental Psychology, 37, 243-250.
  • Girgus, J.S. & A ; Coren, S. ( 1975 ) . Depth cues and stability grading in the horizontal-vertical semblance: The bisection mistake. Canadian Journal of Psychology, 29 ( 1 ) , 59-65.
  • K & A ; uuml ; nnapas, T.M. ( 1957 ) . The vertical-horizontal semblance and the ocular field. Journal of Experimental Psychology, 53 ( 6 ) , 405-407.
  • Ward, L.M. , Porac, C. , Coren, S. & A ; Girgus, J.S. ( 1977 ) . The instance for misapplied stability grading: Depth associations elicited by semblance constellations. American Journal of Psychology, 90 ( 4 ) , 609-620.