An Ames (1951, Psychological Monographs, 65(1, Whole No. 324)) static trapezoidal window, under monocular view, was used to test young infants' responsiveness to pictorial depth. When adults view this display monocularly with the smaller side of the window rotated toward them, they report that the orientation of the display becomes ambiguous: When the head is moved, the window may appear to be in the fronto-parallel plane or either side may appear closer. The 7-month-olds we tested appeared to experience a similar ambiguity; they reached to the near side of the rotated trapezoidal window with significantly less consistency or directedness than infants in a control group tested with a rotated object that lacked pictorial depth information. When 5-month-olds were tested, however, they reached with equal consistency to the closer side of the trapezoidal window and of the control display, apparently uninfluenced by the pictorial depth information available in the trapezoidal window. Thus, sensitivity to the pictorial information for depth that is present in the trapezoidal window appears to develop after the age of 22 weeks.
Bibliographical noteFunding Information:
This research was supported by a fellowship from the Swiss National Science Foundation and byNational Institute of Child Health and Human Development grants to the University of Minnesota’s Institute of Child Development (HD-05027) and to the University’s Center for Research in Human Learning (HD-01136). Correspondence concerning the article and requests for reprints should be sent to Dr. Albert Yonas, Institute of Child Development, University of Minnesota, 51 East River Road, Minneapolis, MN 55455. The authors thank Deborah Miller for editorial assistance.