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This is the first of several studies which will seek to explore perceptual development by means of an original set of ambiguous pictures. In the present study two opposed interpretations of figure-ground reversal were the theoretical starting point. The first interpretation derives from the developmental psychology of Jean Piaget. According to Piaget (9), perception is not an innately fixed mechanism for registering stimuli but is a developing system which becomes increasingly adaptive with age. In the young child perception is passive and dominated by the "best" organization of the visual field. With the development of perceptual operations (internalized actions), however, the child's perception becomes active and spontaneously restructures the field into its many possible organizations. Piaget defines the "decentering of perception" as the development from the passive, "best" form dominated perception of the young child to the active, operation directed, perception of the older child and adult. To make the operational character of perception concrete, consider the following illustrative example taken from Piaget's (9) discussion. Imagine a line drawing of a circle upon a white card and let EA = the enclosed area of the circle, SA = the surrounding area, C = the contour, F the figure, and G = the ground. Now to perceive the contour line as a circle on a white field, the child must perform the following operations: EA + C F; SA C = G. On the other hand, to perceive the contour line as the edge of a hole in a white screen, the child must perform the following operations: EA C = G; SA + C = F. In Piaget's view the ability to perform these operations,3 and thus spontaneously to reverse figure and ground, appears only gradually with increasing age.

"Fifty-six sediment samples were collected within Carmel Bay for textural analysis to determine their statistical properties. The sediments found within the Carmel submarine canyon consist, for the most part, of poorly to very poorly sorted very fine sand and coarse silt. The shelf area surrounding the canyon is primarily comprised of moderately to very poorly sorted sand, with a small area of very poorly sorted gravel in the northeastern section of the bay. Consideration of textural parameters such as mean size, standard deviation, and skewness suggest that the sediments of the bay are under the influence of a dynamic sediment transport mechanisms. The bay appears to be a sedimentary system primarily isolated from adjacent coastal sediment sources, with the major sources of sedimentary deposits being terrigenous debris from the Carmel River, erosion and weathering of the local coastline and offshore rocks by wave and water and the shells and tests of numerous calcareous marine organisms. Movement of sediments by slumping and gravity sliding down the Carmel submarine canyon appears to be the only form of sediment removal within the bay."