Figure 2.

Orientation specificity in contrast learning studied with conventional and TPE procedures. a, The stimulus configuration for contrast discrimination in which one interval contains a higher contrast Gabor stimulus. b, Conventional training. Contrast discrimination for a vertical or horizontal Gabor was practiced (Δcon_ori1; green circles) and the transfer of learning was tested at an untrained orthogonal orientation (Δcon_ori2; red triangles). c, TPE training. Contrast discrimination was practiced at ori1 (Δcon_ori1; green circles; contrast thresholds indicated by the left ordinate) and orientation discrimination (the exposure condition) was practiced at ori2 (Δori_ori2; blue diamonds; orientation thresholds indicated by the right ordinate) in alternating staircases, and the transfer of learning for contrast discrimination was tested at ori2 (Δcon_ori2; red triangles). d, Control. Orientation discrimination was practiced at the transfer orientation (Δori_ori2; blue diamonds) and its impact on contrast discrimination was tested at the same orientation (Δcon_ori2; red triangles). e, A summary of learning and transfer. Left, Conventional training in b; middle, TPE training in c; right, control in d.