Different luminance- and texture-defined contrast sensitivity profiles for school-aged children

Abstract

Our current understanding of how the visual brain develops is based largely on the study of luminance-defined information processing. This approach, however, is somewhat limiting, since everyday scenes are composed of complex images, consisting of information characterized by physical attributes relating to both luminance and texture. Few studies have explored how contrast sensitivity to texture-defined information develops, particularly throughout the school-aged years. The current study investigated how contrast sensitivity to luminance- (luminance-modulated noise) and texture-defined (contrast-modulated noise) static gratings develops in school-aged children. Contrast sensitivity functions identified distinct profiles for luminance- and texture-defined gratings across spatial frequencies (SFs) and age. Sensitivity to luminance-defined gratings reached maturity in childhood by the ages of 9-10 years for all SFs (0.5, 1, 2, 4 and 8 cycles/degree or cpd). Sensitivity to texture-defined gratings reached maturity at 5-6 years for low SFs and 7-8 years for high SFs (i.e., 4 cpd). These results establish that the processing of luminance- and texture-defined information develop differently as a function of SF and age.

Figure 1

Stimuli samples of a luminance-defined grating (luminance modulated noise—left panel) and texture-defined grating (texture-contrast-modulated noise—right panel).

Figure 2

Contrast sensitivity of school-aged children. On the left, contrast sensitivity for luminance-defined gratings as a function of SF across age group is represented. On the right, contrast sensitivity for texture-defined gratings as a function of SF across age groups is represented. The error bars represent the standard error of the mean (some are not visible being smaller than the size of the marker). These graphs are represented on a log–log scale.

Figure 3

Developmental effect of 11–12 years old children versus a control, adult group. On the left, the developmental effect of the 11–12 years old children for each SF of the luminance-defined gratings condition. On the right, the same developmental effect for the texture-defined gratings condition.