Fig. 2.

Comparison of the performance of the three brain-damaged groups and the normals. Each graph represents mean ± SEM of the percent correct responses, or total number of cards selected from the good versus the bad decks, that were made by normal controls (n = 21), by subjects with bilateral orbital and VM frontal lobe lesions (n = 9), by subjects with lesions in the right DL/M sector of the prefrontal cortex (n = 4), or by subjects with lesions in the left DL/M sector of the prefrontal cortex (n = 6). We note that every participant in the delayed response and delayed nonmatching to sample tasks reached a 100% learning criterion at the 0 sec delay before the task could proceed to the 10, 30, or 60 sec delays.