The goal of this proposal is to better characterize face recognition deficits in developmental prosopagnosia (DP) and to further develop effective treatments. This is relevant to the National Eye Institute's mission to better treat visual disorders and understand mechanisms of visual function. The particular goals of this proposal are to better characterize face recollection deficits in DPs and to build upon our previous successes at improving perceptual processing in DPs by incorporating repetition lag training, which targets enhanced face encoding and improved recognition. We hypothesize that this combination training could allow improved perceptual processing to better translate to improved face recognition and reduced symptoms of prosopagnosia. Our aims for this proposal are to: 1) To examine the contribution of recollection and familiarity to face recognition in DPs compared to controls; 2) To determine the effectiveness of combining our validated perceptual training + repetition lag training vs. test-retest control; and 3) To compare the effectiveness of perceptual training + repetition lag training to perceptual training only. To achieve these aims, we propose to perform an in-lab study of 25 DPs and 50 matched controls, where we will use a process dissociation procedure task to measure how recollection and familiarity support old/new face recognition in DPs and controls. We also propose to perform a longitudinal web-based cognitive training study with 60 DPs randomly assigned to three different arms: either 6 weeks of perceptual training, 4 weeks of perceptual training + 2 weeks of repetition lag training, or test-retest waitlist control. Before and after training/waiting, we will assess DPs on a validated online battery of face perception and recognition tests as well as self- reported face recognition. To measure the longevity of potential training effects, DPs performing training will also repeat assessments after a 6-week no-contact period.