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. 2018 Apr 2;28(7):1005–1015.e5. doi: 10.1016/j.cub.2018.02.037

Figure 3.

Figure 3

Predicting the Perceptual Discriminability of the Distractors Using the Classification Images as Spatial Filters

(A) The overlap between the classification image of rat 1 and an example distractor object (3) provides a graphical intuition of the template-matching computation used to infer the discriminability of the distractors from the reference.

(B) Left: prediction of how similarly each pair of rats would perceive the 11 distractors, if the animals used their classification images to process the stimuli. Similarity was measured as the Euclidean distance between the two sets (vectors) of perceptual discriminabilities of the 11 distractors, as inferred by using the classification images of the rats as perceptual filters. Right: estimate of how similarly each pair of rats actually perceived the distractors, with perceptual discriminability quantified using a d′ sensitivity index. Similarity was measured as the Euclidean distance between the two sets (vectors) of d′ obtained, across the 11 distractors, for the two animals. Rats along the axes of the matrices were sorted according to the magnitude of their d′ vectors (from largest to smallest). The red frames highlight two groups of animals with very similar predicted and measured discriminabilities (corresponding to the “good” and “poorer” performers in Figure 2D).

(C) The Euclidean distances in the cells located above the diagonals of the matrices of (B) were averaged, separately, for the rats inside and outside the red frames. The resulting within- and between-group average distances (±SEM) were significantly different according to a one-tailed t test (∗∗p < 0.01 and ∗∗∗p < 0.001, respectively, for the predicted and measured distances).

(D) Relationship between the measured and predicted Euclidean distances corresponding to the cells located above the diagonals of the matrices of (B). The two quantities were significantly correlated according to a two-tailed t test (∗∗p < 0.01).

(E) Relationship between measured and predicted discriminability of the distractors, as obtained (1) by considering all rats and distractor conditions together (left); and (2) after averaging, separately for each animal, the measured and predicted discriminabilities across the 11 distractors (right) (dots show means ± SEM). Both correlations were significant according to a two-tailed t test (∗p < 0.05, ∗∗∗p < 0.001).