Solitary Object Exploration and Play
From the time that they can grasp objects and bring them to their mouths to suck, infants in many cultures spend a great deal of their time exploring, playing with, and otherwise manipulating objects. This is particularly true during the second half year of life, when infants seem bent on putting their hands (or mouths) on everything that they possibly can. Although this is the beginning of an ongoing battle for parents (who quickly learn the limits of their babyproofing skills), it reflects the active attempts of infants to learn about the physical world around them through their actions and their senses. Numerous theorists have written about the intense interest of infants and young children in everyday objects (e.g., Hunt, 1965; Piaget, 1952; Wenar, 1976; White, 1959), and toy manufacturers have benefited greatly from parents' (and especially grandparents'!) awareness of this newfound interest.
Although human children show the greatest levels of object manipulation and play, other animals (especially some birds, carnivores, and primates) also play with objects. Biologists have offered several evolutionary explanations for the existence of object play in animals, many of which may apply equally well to humans.
A problem with the research on object exploration and play is that it is often difficult to differentiate between the playful and nonplayful manipulation of objects ( Weisler & McCall, 1976). At least three forms of object manipulation have been discussed in humans and other animals: object exploration, object play, and tool-use. Numerous studies of undifferentiated object manipulation have been conducted as well, making a review of this literature difficult.
Because of the sometimes subtle differences among object exploration, play, and tool-use, all three behavior patterns are considered in this section.