ABSTRACTSix males were administered a peripheral visual response time test to the onset of brief, small stimuli imaged in 10° arc separation intervals across the dark adapted horizontal retinal meridian under binocular and both monocular viewing conditions. This was done in an attempt to verify the existence of peripheral binocular summation using a response time measure. The results indicated that from 50° arc right to 50° arc left of the line of sight binocular summation is a reasonable explanation for the significantly faster binocular data. The stimulus position by viewing eye interaction was also significant. A discussion of these and other analyses is presented along with a review of related literature.