The first illusion was the Muller-Lyer Illusion. It consists of an arrow shape in which the arrowhead faces different directions. In the middle of the shape is another arrowhead that is supposed to divide the length of the arrow in half. The left-facing arrow illusion did little to affect my perception of the distance. However, I was consistently short on the right-facing arrow. The alignment of the arrow drastically affected my perception. I thought I was consistently dividing it in half, but the results showed otherwise. My average adjusted length was about 5.25% less than the correct length. The Muller-Lyer illusion works by altering our depth perception. Because most of us were brought up in square-cornered houses, the >-< shape appears closer and shorter than the shape. This is because the former looks like the edge of an exterior corner and the latter looks like the edge of an interior corner. This causes our mind to perceive the first shape as shorter than the second one, even though they are the same length. After learning about this phenomenon, my score improved from 5.25% to 3.25%. I still haven’t clearly grasped the concept and been able to perceive it correctly, but I did make a slight improvement. The Ponzo Illusion consists of a red and yellow bar whose heights must be matched. The two bars are placed in a room with the red bar much further back than the yellow bar. My perception was significantly affected by this illusion as I made the yellow bar about 49.5% bigger than red bar, on average. Because of size constancy and the way our brain perceives depth, we often see the red bar as much larger than it really is. This also happens because we perceive it to be much further away from the yellow bar even though it’s only moved towards the center of the picture. I was surprised to discover that on my second attempt, I nearly matched the correct length every single time. I’m generally not good with this sort of visual perception illusion, so I was shocked to discover that I was able to overcome the illusion. The Horizontal-Vertical Illusion consists of matching the length of a vertical line to the length of a horizontal line. I tested fairly well on this one with my vertical line only coming out to be about 4.5% shorter than the horizontal line. The first part of the illusion is a similar effect to the Ponzo illusion. Objects that are closer to the top of our visual field tend to appear as more distant. This means that a vertical line will appear to be longer than a horizontal line of the same length. The second part of this illusion comes as the result of the vertical line bisecting the horizontal line. Most people only focus on half the horizontal line because it is divided, thus drastically over-shortening the vertical line to compensate for it. On the second attempt, my answers were almost exactly correct. I wasn’t really surprised, I was already previously aware of the effects of the illusion. The last illusion is the Poggendorf Illusion. It consists of a box with lines protruding from both sides. My task is to line up the protruding lines so that a diagonal line can be drawn straight through it and reach the second line. This was by far my worst test. The right line, on average, was 61.5 units too near the left line. My perception was significant distorted. The viewer tends to significantly underestimate the distance between the two sides of the box. This harkens back to the earlier Muller-Lyer Illusion. The angles between the box and the segments actually create the halves of the arrowheads used in that illusion. On my second attempt, I was much more accurate and got almost every one exactly correct. After I became aware of the effects of the illusion, I was able to compensate for any changes that my brain perceived.