Figure 2.

Hippocampal damage impairs perceptual judgments based on strength-based relational match, but not those based on discrete states of identifying local differences. (A) Scenes were presented simultaneously for 1.5 seconds, then replaced by a 1–6 scale for a self-paced confidence judgment. The manipulations consisted of contracting or expanding the scenes, keeping the size of the images the same. This changes the configural/relational information within the scenes without adding or removing any objects. In the example shown here, the windows near the center of the building are closer together in the scene on the left than the scene on the right. (B) Aggregate ROCs suggest an impairment in strength-based perception (reduced curvilinearity) in the patients compared to controls, whereas state-based perception (upper x-intercept) is unaffected. (C) Parameter estimates confirm that patients are selectively impaired in strength-based perception; state-based perception is intact. Data for individual patients are overlaid on the patient average; filled shapes are hippocampal patients, open shapes are patients with left (circle) or right (diamond) MTL damage. State- and strength-based perception are on different scales (probability and d′, respectively). Error bars depict +/− 1 SEM.