Figure 2.

The development of spatial resolution in macaque monkeys and humans. Spatial resolution, or acuity, is measured via grating resolution with a combination of forced-choice preferential looking and operant testing methods for both species. The translation to Snellen acuity is represented on the right-hand ordinate. Age is plotted in weeks for macaques and months for humans. Both species show an increase in resolution on the order of a factor of 30 over the course of development. Monkey data are from Kiorpes (1992). Human data are from Mayer and Dobson (1982), redrawn from Kiorpes (2015).