Figure 4.

a–d, IT selectivity and behavioral performance within object sets after training. a, Fraction of IT neurons with responses that were selective among the restricted-experience objects when those objects were tested at the trained retinal position (black bars) and at the nontrained, equally eccentric position (white bars). Data from both monkeys have been combined (Fig. 2). As in Figure 2, selectivity was determined by ANOVA, and the x-axis shows a range of significance levels (p values) used for deeming a neuron to be selective. *p < 0.05, χ² test; significant difference at the trained and nontrained positions. Portions of the bars overlaid in gray indicate the fraction of neurons that were selective at both the trained and nontrained positions. b, Left, Performance of the population of selective IT neurons (p < 0.1, ANOVA) assessed by linear classification (see Materials and Methods), shown separately for each monkey. Chance is 25% (four possible objects). **p < 0.01, test of independent proportions; significant performance difference at the trained and nontrained positions. Right, behavioral performance for one monkey at discriminating among the restricted-experience objects at the trained (black) and nontrained (white) retinal positions (with interleaved low-contrast trials from the bias test object set) (see Materials and Methods). Whereas absolute behavioral performance (b, d, right) is decreased from levels achieved during training because several trial types are interleaved, a strong asymmetry is observed between the trained and nontrained positions for the restricted-experience objects, but not the interleaved bias test objects. **p < 0.01, test of independent proportions; significant difference. c, d, Same conventions as in a, b for the bias test objects, which show no asymmetry between the trained and untrained retinal positions [please note that no direct comparison is implied between the absolute selectivity/performance levels for the restricted-experience (a, b) and bias test objects (c, d)].