Figure 3. Developmental time course for four visual functions in monkeys.
A. Sensitivity to spatial contrast as a function of age (Stavros & Kiopres, 2008); B. Development of ability to discriminate spatial positional offset, or Vernier acuity (Kiorpes, 1992, and unpublished data); C. Development of sensitivity to global structure in concentric Glass patterns (Kiorpes et al., 2012); D. Development of ability to link Gabor elements to form a coherent contour as a function of the density of background noise (Kiorpes & Bassin, 2003). Smooth curves in each panel are Naka-Rushton functions fit to each dataset; the inverted filled triangles along the abscissa indicate the semi-saturation point for the functions, which provide a quantitative metric for the relative maturation of each visual function (see Stavros & Kiorpes, 2008; Kiorpes et al., 2012). Note the relatively late maturation of Vernier acuity compared with the other spatial vision metrics.