Figure 3.

Difference scores of monkeys with PFo lesions (filled symbols) relative to unoperated controls (open symbols). The higher the bar, the greater the response to changes in reinforcer value (solid bars, test 1; hatched bars, test 2). The symbols represent scores for individual monkeys: filled diamond, PFo-1; filled square, PFo-2; filled circle, PFo-3; filled triangle, PFo-4; open circle, Con-1; open right-angled triangle, Con-2; open square, Con-3; open equilateral triangle, Con-4; open plus sign, Con-5; open diamond, Con-6.