Description of Demonstrations

I developed an interactive computer program that allows one to demmtmte and expm'ment with various phenomem in visual perception uciy IBM-compatible computers. The program con-tains modules for demonstrating the color afterimage, the cafe illusion, additiue color mixing and the opponent-process theory of color wision, the glwing axes illusion, the Hermann pid, the McCollough effect, the motion aftereffect, the neon illusion, and simultaneous conwst. The user has considerable control over the stimuli making up the image and um manipulate the variables that conmhute to the perception of the effect. The propam can he used for chsrwm demrmstrations and student h a t m y projects The computer affords many opportunities to present com-plex visual perception demonstrations and experiments in a flexible and cost-effective manner. The primary advantage of the computer is that it replaces bulky equipment that may be expensive to purchase and maintain, time-consum-ing to assemble for each demonstration, complicated to use, and of limitcd function. In this article, I describe a package of computer programs for presenting various sensation-per-ception demonstrations to students. The program can be used as an adjunct to class lectures or for simulating experi-ments in perception. Overview of Program The program will operate with any IRM-compatible com-puter with 640K of random access memory and n VGA screen. All the demonstrations are clustered in a single com-piled program. The main program acts as an interface that allows the user to select the dcmonsrrations using the key-hoard or a mouse. In addition, the interfnce provides access to a help file that presents general information about the operation of the miin proFam m d each of its component demonstrations. For all demonstrations, the user may manipulate one or more variables that affect the particular perceptual phe-nomenon. Changing these variables can he accomplished using the keyboard or a mouse. During the demonstration. the user may call the help file that provides general infor-mation alx~ut the phenomenon heing presented and the program's operation