Introduction to Cognitive Psychology - Department of Psychological ...

Prof. Greg Francis 1/5/11Brightness contrast!! Two receptive fields inside the middle squarereceive the same excitatory and inhibitory signals!! Little responseBrightness contrast!! Receptive fields on the corner!!Receive the same excitation at the center!!differ in the amount of inhibition in the surroundlessinhibitionmoreinhibitionPurdue UniversityPurdue UniversityBrightness contrastBrightness contrast!! Thus, the visual system computes brightness assomething like local contrast!! It’s a property of the center-surround cells!! Our percept of brightness is determined by the responsesof cells at contrast edges!! As a result, things that have equal physical intensities canlook dramatically different (next slide)Purdue UniversityPurdue UniversityBrightness contrastBrightness contrastPurdue UniversityPurdue UniversityPSY 200: Intro. to Cognitive Psychology 2