Abstract
Summary.-(1) Amethod is described whereby a subject is stimulated by a uniformly illuminated circular field of brightness, I, to which maybe added, at intervals of one second, a momentarily illuminated, circular field of brightness, Al. Thresholdvaluesof Alare obtained as afunctionof Ifor 15 combinations of sizes of Al- and I-field. The largest visualfield used has a diameter of 9.6 degrees. The intensity values chosenprovide dataonthe portion of the intensity discrimination curve. (2) Intensity discrimination for a small, foveal Al-field is, over a largerange of adapting intensities, better with no surround than it is with asmall surround. When surround size increases beyond the limits of therod-free area, the intensity discrimination threshold for the small Al-fielddecreases, at high intensities, below the value obtained with no surround.These results are interpreted in terms of a concept of interaction. (3)Ale/I values that lie on the cone portion of the intensity discriminationcurveareloweredonlyslightlyanduncertainlybyincreasesinthediameterof either the Al- or I-field
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
