Project 2 Description
Project two also uses the Method of Adjustment to find a difference threshold. In this project the method of Adjustment is applied to the T illusion. This illusion again demonstrates how our perception of visual phenomena can be influenced by the position of stimuli in relation to each other. As in project 1 you are to do 20 trials of the T illusion. After each trial you are to click the Show Results button and record the percentage shown. Unlike Project 1, the percentage result shown is not a difference but the actual percentage length of the vertical line compared to the horizontal line. After you have recorded the 20 percentages, add them up and get the total, then divide the total by 20. This number is the average percentage length of your adjusted vertical line compared to the horizontal line. Now you have one extra step to do. Take your average vertical line percentage and subtract it from 100%. That result is your difference threshold expressed as a percentage difference between the length of the horizontal and vertical lines. In other words the illusion caused you to see the lines as equal in length when they were actually xx% different.
Use your results to write up your project using the sample project (found on the course shell) as a guide. Your write up will be similar to project 1 except that the illusion used is different. Be sure to read about the T illusion above the Project 2 description