To assess the development of monocular slant perception as well as the relative effectiveness of different sources of information, 90 children in first, third, and fifth grades and 30 college adults were asked to make judgments of surface slant on the basis of monocular texture gradient information. (Author/JH)

Twenty-four subjects at each of four grade levels (first, third, fifth, and college) made judgments of physical slant of surfaces with three levels of variability. Absolute error of judgment decreased with age, but texture variability had no effect at any grade level. (JH)

A total of 125 white children from three counties in Georgia (selected as representative of small rural and medium and large industrial urban populations) were administered a battery of tests in three phases of their schooling: (1) during the summer preceding their admission to the first grade, (2) near the end of the first grade, and (3) near the…