Figure 1.

Infants’ manual actions on objects by object weight. (A) Objects available for free play, ordered by object weight. Colored bars denote the 7 toys available in all 64 sessions; gray bars denote “found” objects available in only 1 to 12 sessions. Analyses included both standard and found objects. (B) Percent of sessions in which infants interacted with each of the 7 standard objects available in every session. (C) Percent of sessions in which infants held light, medium, and heavy objects while walking. Gray bars are necessarily low because found objects were unavailable in most sessions. (D) Percent of walking bouts (striped bars) and standing bouts (solid bars) in which infants held light, medium, and heavy objects. (E) Percent of light, medium, and heavy object holding bouts in which infants both held the object and explored it while walking (striped bars) and standing (solid bars). (F) Percent of light, medium, and heavy holding bouts in which infants held the object unimanually while walking (striped bars) and standing (solid bars). Superscripts in D-F denote differences between conditions.