This study investigates the role of the hippocampus in visual discrimination performance, particularly in tasks involving high feature overlap or ambiguity. Patients with circumscribed hippocampal lesions were tested on their ability to discriminate between similar faces and scenes. The study compared two conditions: a repeated condition where the same stimulus set was used across trials, and a trial-unique condition where each trial was distinct. Controls showed gradual improvement in the repeated condition, indicating learning, but no improvement in the trial-unique condition. In contrast, patients with hippocampal lesions were impaired in the repeated condition but performed normally in the trial-unique condition. These findings suggest that previous reports of impaired discrimination after medial temporal lobe damage may reflect impaired learning rather than visual perception deficits. The study supports the idea that memory is a distinct cerebral function separate from other perceptual and cognitive abilities. The results indicate that hippocampal damage impairs learning but does not affect visual perception itself. The study also highlights the importance of distinguishing between learning and perception in tasks involving visual discrimination. Patients with hippocampal lesions were able to perform normally when each trial was unique, suggesting that their impairment in the repeated condition was due to the inability to learn from repeated stimuli. The study underscores the need to consider the role of learning in tasks involving visual discrimination and the importance of distinguishing between learning and perception in the context of hippocampal damage.This study investigates the role of the hippocampus in visual discrimination performance, particularly in tasks involving high feature overlap or ambiguity. Patients with circumscribed hippocampal lesions were tested on their ability to discriminate between similar faces and scenes. The study compared two conditions: a repeated condition where the same stimulus set was used across trials, and a trial-unique condition where each trial was distinct. Controls showed gradual improvement in the repeated condition, indicating learning, but no improvement in the trial-unique condition. In contrast, patients with hippocampal lesions were impaired in the repeated condition but performed normally in the trial-unique condition. These findings suggest that previous reports of impaired discrimination after medial temporal lobe damage may reflect impaired learning rather than visual perception deficits. The study supports the idea that memory is a distinct cerebral function separate from other perceptual and cognitive abilities. The results indicate that hippocampal damage impairs learning but does not affect visual perception itself. The study also highlights the importance of distinguishing between learning and perception in tasks involving visual discrimination. Patients with hippocampal lesions were able to perform normally when each trial was unique, suggesting that their impairment in the repeated condition was due to the inability to learn from repeated stimuli. The study underscores the need to consider the role of learning in tasks involving visual discrimination and the importance of distinguishing between learning and perception in the context of hippocampal damage.