Although a considerable amount is known about the development of object manipulation during the 1st year, less is known about how infants manually explore surfaces and relate objects to surfaces. To address these issues, 60 infants (20 each at 6, 8, and 10 months of age) were presented hard and soft objects on tabletop surfaces, which varied in terms of their material properties. Tabletop surfaces were either liquid, discontinuous, flexible, or rigid. Results indicated that infants explored the objects, surfaces, and their interactions selectively, tailoring their manual actions to the material properties of the objects or surfaces. In some instances, selectivity increased with age. The implications of these findings for understanding the origins of problem solving and tool use are considered.Over the course of the first year, infants acquire a rich and varied repertoire of actions for manipulating objects. Moreover, infants apply these actions selectively, tailoring a particular kind of movement to an object's unique physical properties. For instance, by the middle of the second half-year, infants finger textured objects more than nontextured ones, shake or bang sounding objects more than nonsounding ones and press pliable objects more than nonpliable ones (Bushnell & Boudreau, 1993;Gibson & Walker, 1984;Lockman & McHale, 1989;Molina & Jouen, 1998;Palmer, 1989; Ruff, 1984).Collectively, these types of achievements belie accounts of sensorimotor development that suggest that object manipulation is undifferentiated during much of the first year. According to such accounts, lack of specificity in infants' manual behaviors stems from a cognitive gap: Infants are not yet fully able to differentiate INFANCY, 8(3),[233][234][235][236][237][238][239][240][241][242][243][244][245][246][247][248][249][250][251][252]
