A Yes-No procedure, combined with the method of limits, is used to measure the size of different visual illusions—the Müller-Lyer illusion, the horizontal-vertical illusion, or the simultaneous contrast illusion. This enables the student to experimentally determine the features of each stimulus responsible for the illusion. iNSIGHT is a curriculum supplement for experimental psychology, sensation and perception, vision science, and optometry lab classes. There are two different types of iNSIGHT apps: experiments and interactive demonstrations. Experiments are real psychophysical procedures (NOT simulations) that generate real data. Demonstrations illustrate a visual phenomenon and allow students to manipulate the effect. Each lab is complete with a quick-start guide, detailed instructions, background information, and one or more guided exercises. To see how iNSIGHT works, try the FREE iNSIGHT Color Mixing app. A printable PDF Student Guide that contains the exercises and other supporting materials, and a Teacher Guide are available at www.polyhedronlearning.com/see_apps_insight.html
