The study by Bertenthal, Campos and Haith, indicating that 7-month-olds but not 5-month-olds dishabituated when a stimulus changed between showing an illusory contour and not, demonstrates that the 7-month-olds a.perceive a change in the size of the illusory square, indicating that it had also changed in depth. b.are perceptually sensitive to the orientations of the pacmen. c. are able to perceive the whole stimulus as distinct from its parts. d. perceive a square that is in front of and occludes four circles that are at a different depth.

The study by Bertenthal, Campos and Haith, indicating that 7-month-olds but not 5-month-olds dishabituated when a stimulus changed between showing an illusory contour and not, demonstrates that the 7-month-olds