The various ways that objects are used by children has been subjected to a considerable amount of theoretical and empirical attention across a number of different disciplines, from anthropology (e.g., Bock, Reference Bock, Pellegrini and Smith2005) to developmental psychology (e.g., Piaget, Reference Piaget1952) and zoology (Beck, Reference Beck1980). Perhaps most centrally, Piaget’s (Reference Piaget1952) theory suggests that children’s cognitive development is rooted in their sensorimotor interactions with objects. In this theory, individuals construct representations for those objects and their associated actions through repeated interactions. Piaget’s sensorimotor theory has also been applied to the use of objects in non-human primates (Hallock & Worobey, Reference Hallock and Worobey1984). Furthermore and by extension, one school of thought holds that human cognition evolved in the context of apes’ manipulation and use of objects and tools (Tomasello & Call, Reference Tomasello and Call1997). However, much of what developmental psychologists know about children’s object use, especially during infancy and early childhood, is often subsumed under the labels ‘object play’ and ‘construction’. These labels have been used so loosely that it is very difficult to chart ontogenetic or functional courses for the diverse ways in which children use objects. A basic premise of ethology (Tinbergen, Reference Tinbergen1963), and this chapter, is that behavior categories should be induced through empirical observation and hypotheses tested subsequent to this.
Further, the importance of social interaction around object uses in early cognitive development, especially in Piaget’s theory, has been ignored. This view persisted even though there were numerous observations, especially involving young children, that interactions with objects take place in a social contexts and that children spend considerable time observing others using objects (e.g., Tomasello & Call, Reference Tomasello and Call1997). Unfortunately, however, the extant child developmental literature on object uses pays only limited attention to the ways that different types of object are used in a variety of social as well nonsocial contexts (though see Flynn & Whiten, Reference Flynn and Whiten2008, and Pellegrini & Hou, Reference Pellegrini and Hou2011).
In this chapter I will first describe the different forms of object use (i.e., exploration, construction, play, tool use, and tool making) in childhood. This is an important exercise given the variety of labels used to describe the different ways that children interact with objects. Correspondingly, I will establish time budgets for each type of object uses and make functional inferences about each and the social context in which each is embedded.
Object Uses in Childhood
Given the centrality of object use in child developmental theory, it is surprising how little descriptive information there is about the varied ways in which children use objects. Where efforts have been made to address the different types of object use and play exhibited by children, researchers have often conflated object play with different forms of object use. Specifically, much of the study of children’s interactions with objects during childhood has been influenced by Smilansky’s (Reference Smilansky1968) adaptation of Piaget’s (Reference Piaget and Paul1951) theory of play and the ways that she categorized behaviors directed at objects as ‘constructive play’, an ends-oriented activity with objects where something was built. Piaget, in contrast, did not consider construction to be play because of its ends, not means, orientation (Smith et al., Reference Smith, Takhvar, Gore, Volstedt and Smith1986). I will discuss each form of object use, in the order in which they occur in ontogeny.
Exploration
Exploration is the behavior exhibited when individuals first encounter unfamiliar objects; they manipulate, or explore, their properties and attributes (Hutt, Reference Hutt1966; West, Reference West1977). Through exploration, children find out that objects, for example, are flat or rounded, long or short. While often conflated with play with objects, they differ behaviorally. Specifically, exploration, relative to play, is characterized by elevated heart rate, low distractibility, and negative/flat affect. By contrast, children playing with objects have lower heart rates, are highly distractible, and display positive affect (Hutt, Reference Hutt1966).
Further, exploration precedes other forms of object use, including play in human ontogeny (Belsky & Most, Reference Belsky and Most1981; McCall, Reference 181McCall1974), as well in other animals (e.g., West, Reference West1977). In a study of children from 7.5 to 21 months, Belsky and Most found that exploration of toys was the predominant activity of the youngest children (7.5–10.5 months), with no instances of pretend play with objects. From around 9–10.5 months, children named objects as they manipulated them. At 12 months, pretend play with objects appeared, co-occurring with exploration and naming of the objects, and then pretend displaced exploration. And, like Hutt (Reference Hutt1966), Belsky and Most (Reference Belsky and Most1981) noted that exploration of an object precedes play with that object. These trends are consistent with a view that the processes involved in exploring are precursors to play with objects.
By the time children are of preschool age, exploration accounts for a relatively small portion of their object time budgets, between 2% and 15% of children’s total observed behaviour (Pellegrini & Gustafson, Reference Pellegrini, Gustafson, Pellegrini and Smith2005; Pellegrini & Hou, Reference Pellegrini and Hou2011). In the case of the high end of the range, exploration spikes when children are exposed to novel objects, such as when they return to their preschool classrooms after their winter holidays. Given the relative infrequency of exploration during the preschool years, there are few documented age differences for directly observed exploration (Pellegrini & Gustafson, Reference Pellegrini, Gustafson, Pellegrini and Smith2005), though differences do appear when the construct is widened to include such behaviours as asking questions and other elicited behaviours (Henderson & Moore, Reference Henderson and Moore1979).
There are reported sex differences in exploration, where boys exhibit more than girls (Pellegrini & Hou, Reference Pellegrini and Hou2011), though experimental study of infants’ and pre-schoolers’ exploration do not consistently test for sex differences (e.g., Ross et al., Reference Ross, Rheingold and Eckerman1972).
Exploration of objects occurs in both social and solitary contexts. Piaget (Reference Piaget1967) described how solitary infants, especially, as well as young children explored objects, yet children’s exploration can be facilitated by adults, such as parental presence (Rheingold & Eckerman, Reference Rheingold and Eckerman1970). Adult facilitation continues through early childhood (~ 5.5 years of age), where adult encouragement significantly increases exploration (Henderson, Reference Henderson1984). However, we find that when children explore objects in preschool classrooms, they tend to do so in solitary contexts (Pellegrini, unpublished data). Correspondingly, preschool children’s exploration does not attract their peers’ attention (Pellegrini & Hou, Reference Pellegrini and Hou2011).
Play with Objects
Play, following Burghardt (Reference Burghardt2005), should be defined categorically, not continuously, and must meet all of the following criteria: voluntary, observed in a ‘‘relaxed field,’’ not completely functional in the immediately observed context, and have elements that are exaggerated, segmented, and nonsequential in relation to the functional behavior. A relaxed field is one in which the individual, typically a juvenile, is well provisioned, safe, and healthy. Further, the child voluntarily chooses to engage in an activity that is not completely functional. The nature and sequence of these behaviors should not resemble those in a functional context. For example, a child could approach a peer, take an exaggerated swipe at his peer, fall to the ground, and then switch roles, so his peers can hit at him. Distilling Burghardt’s definition, I suggest that the most important criteria are the emphases on means over ends and incompletely functional behavior in the immediate context because they are probably antecedents, and sufficient conditions, for children generating novel behaviors. That is, by not being concerned with the usefulness of behavior, individuals are free to experiment with its form and place in behavioral sequences (e.g., Bateson, Reference Bateson, Pellegrini and Smith2005; Fagen, Reference Fagen1981). The resulting behavioral and cognitive flexibility characteristic of different forms of play, such as exaggerated, non-sequential, and segmented behavioral routines, is crucial to the development of what Bruner (Reference Bruner1972) and West-Eberhard (Reference West-Eberhard2003) labeled behavioral ‘modules’.
From this definition, object play typically involves pretending with an object. Using objects in pretend initially entails that children are simulating someone else’s use of those objects. With experience, children learn to have more abstract objects represent other objects. Correspondingly, children’s play with objects is typified by them using objects in novel and varied ways (Pellegrini & Hou, Reference Pellegrini and Hou2011). This begins in the context of parent–child interactions (and then to interaction with peers; Lillard, Reference Lillard, Göncü and Gaskins2006). Indeed, of all the ways in which children use objects, play with objects is most highly related to creative uses of objects (Pellegrini & Hou, Reference Pellegrini and Hou2011).
Play with objects, like other forms of play, follows an inverted-U function; it first appears at around 12 months of age, increases through the preschool years, and then declines (Fein, Reference Fein1981). Establishing an accurate time budget for play with objects during childhood is difficult because object play has typically been conflated with other forms of object use. In those cases where object play was clearly differentiated from other forms of object use, it begins at around one year (Belsky & Most, Reference Belsky and Most1981) and increases among 3- to 5-year-olds in US and UK preschool settings to 18%–30% of children’s time budgets (McGrew, Reference McGrew1972; Pellegrini & Gustafson, Reference Pellegrini, Gustafson, Pellegrini and Smith2005; Pellegrini & Hou, Reference Pellegrini and Hou2011).
Given the clear differences in antecedents, ontogeny, and function between play and exploration, it is confusing when the terms are used interchangeably and in combination (i.e., ‘exploratory play’), even within the same research articles (e.g., Baldwin et al., Reference Baldwin, Markman and Melartin1993), to describe exploration as defined in this chapter. Such loose word usage has confused, and will continue to confuse, the meaning of each construct and further muddy the play and object use literatures. Correspondingly, it is nearly impossible for researchers to document time budgets of different types of behaviour during childhood, when terms are not used accurately and consistently. Perhaps most basically, when behavioural categories are not based on empirical observation, as exists between play and exploration, our theories and subsequent hypotheses will remain on the borders of science; from my view, science should involve both induction (to empirically form categories) and deduction (to test hypotheses) (Russell, Reference Russell1931/1959; Smith, Reference Smith and Pellegrini2011; Tinbergen, Reference Tinbergen1963).
Sex differences in object play are equivocal and not consistent with the more general literature on pretend play where girls, relative to boys, exhibit more and more sophisticated pretend (Pellegrini, Reference Pellegrini2009). In an observational study of pre-schoolers’ object use (i.e., exploration, construction, object play, and tool use) across one year, object play was not influenced by sex (Pellegrini & Hou, Reference Pellegrini and Hou2011). It may be that in this study girls’ general facility with pretence was diluted by their interactions across a wider variety of objects (beyond replicate toys), while boys’ play with some forms of objects (such as using a rake for a pretend gun) increased, thus attenuating sex differences.
Object play becomes increasingly social with age (Rubin et al., Reference Rubin, Fein, Vandenberg and Hetherington1983). For example, less than 2% of preschool and kindergarten children’s play is solitary, while 12% and 28% of pre-schoolers’ and kindergarteners’, respectively, is social (Rubin et al., Reference Rubin, Watson and Jambor1978). Thus, not only does object play increase across childhood, but it also becomes increasingly social.
Construction
Much of what we know about construction is subsumed under the Smilansky-inspired label of ‘constructive play,’ which, according to Smilansky, has the child learning the “various uses of play materials” and the “building” of something (Reference Smilansky1968, p. 6). However, construction, according to Piaget (Reference Piaget and Paul1951) and others (e.g., Smith et al., Reference Smith, Takhvar, Gore, Volstedt and Smith1986), is not considered to be play. For Piaget, on whom Smilansky based her work, construction is more accommodative and concerned with the end product of activity – the construction per se – while play is more assimilative and concerned with the activity, or means, than with the end and consequently is not play per se (Piaget, Reference Piaget and Paul1951). In further support of the claim that construction is not a form of play, it does not follow the typical inverted-U age-related trajectory (Smith et al., Reference Smith, Takhvar, Gore, Volstedt and Smith1986)
Smilansky’s categories of ‘play’ were expanded into a heuristic for describing the social and cognitive dimensions of play by Rubin and colleagues (Reference Rubin, Fein, Vandenberg and Hetherington1983) and considered ‘constructive play’ as the manipulation of objects to create something. This scheme has been used to generate massive and valuable amounts of descriptive data on the ways that young children use objects (summarized in Rubin et al., Reference Rubin, Fein, Vandenberg and Hetherington1983). Rubin and colleagues rightfully questioned the validity of ‘constructive play’ as a form of play because of its incongruity with Piagetian theory. Despite these qualifications, little effort has been made to differentiate construction from play with objects and other forms of object use.
The above definition given by Smilansky, and subsequently revised by Rubin et al. (Reference Rubin, Fein, Vandenberg and Hetherington1983), includes a diverse constellation of goal-directed and non-goal-directed uses of objects. For example, using blocks to build steps might be considered constructive or pretend play. The same act, however, might also actually be considered ‘tool use’ if a child uses the steps to enhance his or her reach (Amant & Horton, Reference Amant and Horton2008). Thus, the descriptive data generated by the Smilansky model provide very general descriptions of children’s object use. However, to the extent that the category ‘constructive play’ is too general it limits our knowledge of the role of ‘object play’ and construction in children’s development
‘Constructive play’, as defined by Rubin and colleagues, has been found to account for between 40% (Rubin et al., Reference Rubin, Maioni and Hornung1976) and 51% (Rubin et al., Reference Rubin, Maioni and Hornung1976, Reference Rubin, Watson and Jambor1978) of all observed behaviour subsumed under the Smilansky–Parten play matrix. When construction is defined more consistent with Piaget (Reference Piaget and Paul1951), Pellegrini and colleagues found that construction accounted for between 15% (Pellegrini & Gustafson, Reference Pellegrini, Gustafson, Pellegrini and Smith2005) and 17% (Pellegrini & Hou, Reference Pellegrini and Hou2011) of behaviour. The very different figures derived from the Rubin and Pellegrini studies may reflect the fact that what Rubin and colleagues coded as constructive play probably included other forms of object use, such as tool use and perhaps solitary object play.
In terms of sex differences for ‘constructive play’, defined according to Smilansky, it is reported that females engage in more than males (Rubin et al., Reference Rubin, Maioni and Hornung1976; Rubin et al., Reference Rubin, Watson and Jambor1978). However, boys’ constructions tend to be more complex than girls’ (Rubin et al., Reference Rubin, Fein, Vandenberg and Hetherington1983). Data from two naturalistic studies of pre-schoolers’ object use using the differentiated categories proffered here help to clarify this confusion. Beginning with an observational study with a limited sample, girls, relative to boys, spend more time in construction, but boys spend more time than girls in object play (Pellegrini & Gustafson, Reference Pellegrini, Gustafson, Pellegrini and Smith2005). In the other, larger observational study, there were no moderating effects of sex on construction (Pellegrini & Hou, Reference Pellegrini and Hou2011).
Tool Use and Tool Making
Tool use has individuals using objects not attached to the environment or being part of individuals’ bodies, in the service of a goal, such as getting food, and includes both using and making tools (Hansell & Ruxton, Reference Hansell and Ruxton2008). For example, using a fingernail to twist a screw would not be an example of tool use but using a screwdriver would; shaping the tip of a stick to do so would be an example of tool making. Thus, tool use is a convergent activity, involving children learning to use a tool according to cultural conventions, such as using a fork, while making tools is a more divergent and creative act such that individuals use an object to solve a problem for which it might not have been designed; for example, bending a coat hanger to retrieve an object in a remote location. Using tools instrumentally, relative to making tools, appears relatively early in human ontogeny (Mounoud, Reference Mounoud, Sameroff and Haith1996), with skills increasing from infancy through childhood (Connolly & Elliot, Reference Connolly, Elliott and Blurton Jones1972).
Most studies of tool use in childhood showing increases in facility with age are drawn almost solely from performance on experimental tasks (Flynn & Whiten, Reference Flynn and Whiten2008). Developmental descriptions of children’s use of objects in children’s everyday worlds, encompassing exploration, play, construction, and tool use, are sorely lacking (Power, Reference Power2000), thus time budget information is spotty. There is an especial paucity of studies of children’s making of tools and innovation in making tools. Three studies, two with university laboratory pre-schoolers and one with African pastoral children, however, provide a relatively consistent picture. First, regarding the university preschool samples, Pellegrini and colleagues (Pellegrini & Gustafson, Reference Pellegrini, Gustafson, Pellegrini and Smith2005; Pellegrini & Hou, Reference Pellegrini and Hou2011), observed preschool children’s tool use and making in their classrooms. Children spent between 19% (Pellegrini & Hou, Reference Pellegrini and Hou2011) and 23% (Pellegrini & Gustafson, Reference Pellegrini, Gustafson, Pellegrini and Smith2005) of their total observed time in tool use. Only in the later study (Pellegrini & Hou, Reference Pellegrini and Hou2011), however, was the sample large enough to calculate a growth curve model, which showed a significant increase in tool use across time. Similarly, in Bock’s (Reference Bock, Pellegrini and Smith2005) pastoral sample of Botswanan preschool-age children, they spent a similar amount of time in object use, 17%, similar to the figures in the Pellegrini studies.
Unlike using tools, tool making is still developing through the early and middle childhood periods, indicative of the relatively complex dexterity and cognition needed (Monound, Reference Mounoud, Sameroff and Haith1996). Making tools is cognitively complex to the extent that individuals must identify a goal, identify affordances in objects associated with the goal, and consider the means of using tools to meet that goal. Further, the ability to make tools requires a level of behavioural flexibility, such that rather conventional objects, such as pipe cleaners, are redesigned to serve different ends, relative to what they were designed for (Cutting et al., Reference Cutting, Apperly and Beck2011). However, when even very young children (e.g., 30 months of age) observed someone else make a tool, they were able to imitate them (Hayne et al., Reference Hayne, Herbert and Simcock2003). However, when they are left on their own, they do not make tools to solve problems successfully until well into middle childhood (Monound, Reference Mounoud, Sameroff and Haith1996).
The supportive role of adults in children’s tool use and tool making suggests that infants’ and young children’s interest in objects is stimulated when they are interacting with or observing adults using objects. When adults handle objects, for example, children, in turn, become interested in those objects; they may pick up the objects, examine them, and learn about them (Tomasello & Call, Reference Tomasello and Call1997). Relatedly, when infants or young children observe adults handling and using objects to solve a problem, such as using a coat hanger to retrieve a toy, they recognize that the hanger can be used to solve the problem and they use it, though not as demonstrated by the model, to solve the problem, something that they might not have discovered on their own (Tomasello & Call, Reference Tomasello and Call1997). The ease with which child emulate and imitate adults using tools, relative to their independent performance, is testament to the importance of the social context of learning to use tools. However, when children’s tool use is observed in their preschool classrooms, it occurs in both social and solitary contexts and does not attract a significant amount of their peers’ attention (Pellegrini & Hou, Reference Pellegrini and Hou2011).
Sex differences in tool use are equivocal, perhaps due to the different ways in which it is defined and contexts in which it is assessed. Specifically, studies of preschool children’s tool use are either naturalistic or experimental and in the experimental cases often involve tool making inspired by the Köhler-type (Reference Köhler1925) lure retrieval tasks. In some of this work (i.e., tool use tasks) preschool children are presented with an array of objects, some of which are tools that can solve the problem (retrieve the lure). In these tool choice experiments, children as young as 2 years of age chose the optimal objects to retrieve the lure (e.g., Chen & Siegler, Reference Chen and Siegler2000); boys seem better at this than girls, though with minimal help, the sex differences are attenuated.
In terms of sex differences in tool use in naturalistic studies, neither of the Pellegrini and colleagues’ (Reference Pellegrini, Gustafson, Pellegrini and Smith2005, Reference Pellegrini and Hou2011) studies nor the Bock (Reference Bock, Pellegrini and Smith2005) study found significant sex differences in time spent in total tool use. However, sex differences were observed when the specific tools used were disaggregated from total tool use. Among pastoral children studied by Bock (Reference Bock, Pellegrini and Smith2005), girls spent more time than boys ‘play pounding’, which involves using mortar-like objects, such as sticks and reeds, to pound grain-like substances. Girls also moved from play pounding to actual tool use, helping adults to pound grain, at an earlier age than boys moved from playful tool use to actual tool use. Boys spent more time than girls in throwing spear-like sticks at targets, and boys were older when they moved from such playful tool use to real hunting. In the case of foraging children, Gosso and colleagues (Reference Gosso, Otta, Morais, Ribeiro, Bussab, Pellegrini and Smith2005) reported boys more than girls were frequently seen using bows and arrows and slingshots, whereas girls more frequently made tools associated with gathering (for example, making baskets out of palm leaves; indeed, this activity was observed exclusively among girls). So the sex differences observed in some of the experimental studies of children’s tool use may be specific to those tasks, rather than a more general sex-related behaviour.
Putative Functions of Object Use
Making inferences about the function of a behavior can be done in a number of ways, including its beneficial consequences and in terms of ‘ultimate function’, or reproductive fitness (Hinde, Reference Hinde1980). Perhaps the most frequently cited efforts to determine function of object play in the developmental psychological literature involve experimental manipulations where children are ‘trained’ to play with objects and then they are given similar or different, objects in convergent or divergent problem-solving tasks.
Convergent tasks are often modelled after Köhler’s (Reference Köhler1925) famous experiments of a chimpanzee using objects to solve problems, such as putting together sticks to reach bananas hung above its head. In the paradigmatic child development experiment in this mould, Sylva and colleagues (Reference Sylva, Bruner, Genova, Bruner, Jolly and Sylva1976) presented children with disassembled components of a tool (i.e., sticks and clamps) that had to be assembled in order to retrieve a lure, such as a toy. Children in different conditions were given opportunities to play with the unassembled sticks, observe an adult assemble the sticks, or watch an adult use the clamp non-functionally (a control condition). Play condition children, relative to other conditions, were more systematic in their problem-solving, moving from simple to complex moves and using information from hints and failures more effectively. These findings, however, do not replicate under double-blind conditions (Simon & Smith, Reference Simon and Smith1983).
Using objects in divergent problem-solving situations, or tasks for which there is no one correct answer, is also very common in the child development literature (Sutton-Smith, Reference Sutton-Smith1967). Specifically, Dansky and Silverman’s (Reference Dansky and Silverman1973, Reference 180Dansky and Silverman1975) frequently cited experimental studies examined the effects of ‘play’ with objects on children’s associative fluency, or creative uses for objects. In the first study, Dansky and Silverman (Reference Dansky and Silverman1973) provided children with conventional, but unfamiliar, objects. In one condition they were asked to play with the objects; in others they observed an adult manipulating the objects or were exposed to a control condition. These sessions lasted less than 10 minutes. Children were then asked to list all the uses possible for one of the objects to which they were exposed. For example, creative uses for a matchbox might include using it as a pretend boat. They found that children in the play condition generated the greatest number of creative responses, relative to children in the other conditions.
In the second experiment by Dansky and Silverman (Reference 180Dansky and Silverman1975), children were assigned to similar conditions to those in the first experiment, but then asked to generate creative uses for objects with which they did not interact in their respective treatments. Again, they found that children in the play condition, relative to the other conditions, were the most creative, arguing that effects were due to an induced ‘play set,’ a temporary, creative orientation to objects presented.
While being widely cited, these studies of associative fluency, like the study by Sylva and colleagues, do not replicate when double-blind procedures are used (Smith & Whitney, Reference Smith and Whitney1987). The results in both types of studies, then, were probably due to experimenter bias. Furthermore, one could question the efficacy of an experimental treatment of 10 minutes or so on children’s behaviour. An alternative, and perhaps more valid, approach to documenting the role of object play and exploration in tool use would involve documenting the time children spend in different types of object use across a relatively long period of time in their natural ecologies, and then regressing those values onto children’s performance in different object use tasks (Pellegrini & Gustafson, Reference Pellegrini, Gustafson, Pellegrini and Smith2005). This larger corpus of observations should provide a more valid indicator of children’s facility with objects, relative to the relatively short-term studies cited earlier.
Martin and Caro (Reference Martin, Caro, Rosenblatt, Beer, Bushnel and Slater1985) suggest that if play, or any other form of object use, is to be naturally selected, benefits associated with the construct should outweigh the costs. An important first step in establishing function from this perspective is to document costs and then relate those costs to a beneficial consequence and/or fitness. Time spent in different types of activities with objects during childhood can be framed in this study in terms of behavioural ecology theory advanced by van Schaik (Reference van Schaik, Deaner and Merrill1999) and colleagues where descriptions of the ‘costs’ associated with an activity serve as an indicator of its importance, or possible function. Costs are typically documented in terms of the resources (time, energy, and survivorship) expended to acquire or learn a skill. Time in an activity is typically expressed as the portion of the total time budget spent in that activity and energy is typically expressed in terms of caloric expenditure in that activity relative to the entire caloric budget (Pellegrini et al., Reference Pellegrini, Horvat and Huberty1998).
The logic of this level of analysis is as follows. Learning and developing specific skills involve different trade-offs between costs and benefits, and individuals tend to adopt the most ‘efficient’, or optimal, strategies to solve different problems at specific points during ontogeny (Krebs & Davies, Reference Krebs and Davies1993). For example, in learning to use tools during childhood, trade-offs are made between different opportunities (e.g., playing with objects vs. learning to use an object through observation or direct instruction) in light of the finite amount of time and calories available. From this view, there should be a correspondence between time budgets and the benefits associated with expenditures in each activity: time spent in different types of activity use should relate positively to using those objects to solve problems.
There are very few time and energy budget studies of children’s play, generally (though see Haight & Miller, Reference Haight and Miller1993, for pretend play, and Pellegrini et al., Reference Pellegrini, Horvat and Huberty1998, for locomotor play), and specifically for object use (though see Bock, Reference Bock, Pellegrini and Smith2005; Pellegrini & Gustafson, Reference Pellegrini, Gustafson, Pellegrini and Smith2005; Pellegrini & Hou, Reference Pellegrini and Hou2011). The problem with documenting costs of object use and object play is compounded with the use of very loose and inconsistent terminology surrounding object use, as discussed above. Consequently, I will use data from the two Pellegrini studies (Pellegrini & Gustafson, Reference Pellegrini, Gustafson, Pellegrini and Smith2005; Pellegrini & Hou, Reference Pellegrini and Hou2011) because they used definitions consistent with those presented here and they were put in time budget terms. Pellegrini and Gustafson (Reference Pellegrini, Gustafson, Pellegrini and Smith2005) observed a modest sample (N = 35) of preschool children in their classrooms across one school year. The aim was to use children’s object use sampled across the year to predict the use of objects to solve divergent and convergent object-related problems. A subsample (N = 20) of children were also asked to participate in three types of object-use tasks (two convergent and one divergent tool task) as well as a spatial IQ task.
The divergent problem-solving task was assessed with an associative fluency task. The first of the two convergent retrieval tasks involved selecting a tool (e.g., a plastic toy hoe, a plastic rake head without a handle) with which to retrieve a toy dinosaur that had been placed out of reach of the child. In the second convergent task, children were asked to make a tool from Tinkertoy parts and then use it to retrieve a toy. Children were also given a series of seven graded hints if they stalled. The hints were provided in a sequential order but in ways that were appropriate to the phase of the task in which the child was engaged. The hints also provided the child with gradually more specific help in accomplishing the second task. The following dimensions of each child’s performance were scored: the total time needed by the child to use one or more of the objects to successfully retrieve the dinosaur, the number of hints provided to the child by the experimenter while completing the task, and the number of swipes (e.g., attempts to use one or more of the objects to retrieve the dinosaur).
There was a paucity of predictive relations between observed object uses and performance on the associative fluency task and on the connected and unconnected lure-retrieval tasks, when spatial IQ was controlled. That exploration was a very low-occurrence behaviour may be partially responsible for these results given the age of the children and the relative familiarity of the objects in the classrooms
Construction and tool use did, however, differentially predict performance on the problem-solving tasks: construction was a significant predictor of associative fluency and performance on the connected tool use retrieval task (time to complete and hints), but it did not predict performance on the making tool (unconnected) task: observed tool use predicted number of hints on the tool-making task. The unconnected task was more difficult than the connected task, as indicated by the differences in time and hints needed to solve each. The time needed to complete the unconnected task was also greater by a factor of four than the connected task, and more than double the number of hints was needed.
Given the paucity of relations between object uses and performance on any of the problem-solving tasks, we might question the often-trumpeted value of play for both convergent and divergent problem-solving tasks with objects, at least as measured in associative fluency and lure retrieval tasks, similar to the argument made by Smith (Reference Smith and Pellegrini1988). While this may be true for lack of effects on the lure retrieval tasks, which involve making tools, it is also possible that the task of making tools to retrieve lures is simply too complex for preschool-age children (Mounoud, Reference Mounoud, Sameroff and Haith1996), even though they are capable of choosing the correct tool at a much younger age. As for the lack of relations for divergent, creativity tasks, it may be, again, that the choice of the task itself is inadequate. Specifically, we might be better served by redefining creative uses of objects in terms of behavioural ‘modules’ and the social learning implications of others observing novel modules. Modules, as defined by Bruner (Reference Bruner1972) and more recently by some evolutionary biologists (e.g., West-Eberhard, Reference West-Eberhard2003), develop as responses to local ecological and material demands. I do not use ‘module’ to refer to ‘innate’ brain structures in the same way as some evolutionary psychologists (e.g., Cosmides & Tooby, Reference Cosmides, Tooby and Dupre1987). Modules, as I use the term, are relatively novel actions constructed by individuals in response to new environments. With experience, these diverse behavioural routines become more focused and relevant to the environments and objects in which individuals are embedded. Speculatively, it may be that play with objects results in the generation of behavioural modules associated with and independent of objects.
Take, for example, a child engaged in object play with pipe cleaners where he connects and bends two separate pipe cleaners into a pretend ‘tunnel’ for him to drive his toy car through. This specific module of connecting and bending could then be used on similar materials to solve a problem, such as connecting and bending pipe cleaners to be used to retrieve a lure in a restricted physical space. Correspondingly, modules developed in play can be applied to very different types of objects, for example, attaching lengths of rope to make it long enough to pull a wagon.
Further and perhaps more crucially, the social learning implications of novel object use may be the most important function of object play, though it has been virtually ignored, with Bateson (Reference Bateson and Pellegrini2011) and Pellegrini and Pellegrini (Reference Pellegrini, Pellegrini, Narvaez, Panksepp, Schore and Gleason2013) being notable exceptions. They suggested that the behavioural flexibility developed in play may be an evolutionary driver, and at the leading edge of evolutionary change (though see Hewlett & Boyette, Reference Hewlett, Boyette, Narvaez, Panksepp, Schore and Gleason2013, who challenged this as regards hunter-gatherer societies). That is, novel behaviours could be generated in play because of its high intrinsic motivation and its lack of concern for instrumentality. Those novel behaviours that out-compete alternatives will spread through the population and become dominant, in what I label the ‘seeding hypothesis’ of play. These novel uses should, in turn, attract the attention of peers (Pellegrini & Hou, Reference Pellegrini and Hou2011) and may spread through the population, depending on their usefulness. This hypothesis is consistent with early work with chimpanzees (Chance, Reference Chance1967), where researchers gauged peer responses to individuals’ novel and varied uses of objects by documenting ‘attention structure’, or the number of chimpanzees looking at chimpanzees as they used objects in different ways.
From this argument, Pellegrini and Hou (Reference Pellegrini and Hou2011) observed a children’s object use across a year in university nursery school classrooms. Object use was coded as exploration, play, construction, and tool use; each use was also independently scored for novelty and variety. Consistent with claims that object play is a mechanism for generating novel behaviour, they, like Hutt and Bhavnani (Reference Hutt and Bhavnani1972), found that only object play, not other forms of object use, significantly predicted novelty. As an indicator of the discriminant validity of the claim that play is a novelty generator, exploration, a convergent activity, was negatively and significantly correlated with novelty. That this study found a relation between object play and novel uses of objects may be due to the fact that it sampled novel behaviours more widely than experimental studies, which typically used a single, short-term, contrived task.
Specific to the ‘seeding hypothesis’, Pellegrini and Hou also found that only novel and creative uses of objects correlated significantly with peer attention structure. Further, novel and creative uses of object play observed during the first quarter of the school year predicted peer attention structure of children using objects creatively in the final quarter of the year, with attention structure for the earlier period statistically controlled. Again, this adds support to the claim that novelty attracts peers’ attention, while construction, a convergent activity, was a significant negative predictor.
Also consistent with our findings, Wilks and colleagues (Reference Wilks, Collier-Baker and Nielsen2014) found that children copied groups of other children who used objects effectively to solve problems (i.e., the majority bias). It may be that the novelty and effectiveness co-occurred in this experiment, but future research should tease apart the relative attractiveness of children who exhibited either novel or effective object use strategies. While these are results in need of replication, they do suggest that in trying to determine a function of object play researchers may have been off mark on two points. First, they targeted facility in specific tasks, such as associative fluency and lure retrieval tasks, rather than in a more general tendency to use objects in novel and varied ways. Second, and relatedly, researchers in this literature have virtually ignored the social dynamics of such behaviour. It may be that an important function of object play, and perhaps of play more generally, is to provide models to conspecifics of individuals exhibiting these behaviours, in the same way that human (Pellegrini, Reference Pellegrini2009) and non-human (Chance, Reference Chance1967) individuals attend to socially dominant members of their group. Paying attention to these individuals may benefit individuals and groups, in turn. Learning to use objects in novel ways via imitation and other forms of social learning is a more effective strategy than having individuals spending time and energy constructing their own modules (Boyd & Richerson, Reference Boyd and Richerson1985).
While this is possible, researchers must also address the counterclaim that it is not ‘economical’ for innovative players to share their creations, adding a cost to innovation and thus not likely to be selected (Fagen, Reference Fagen1981). Specifically, there are costs as well as benefits incurred by innovators, while there may be fewer costs and equally high benefits for copiers of innovations. That is, it takes less time and energy to observe an innovation, relative to playing and experimenting with objects, and the innovators are not getting pay-back for their investment if peers can copy, at less cost. This argument is, however, predicated on the assumption that individuals compete with each other for resources and that innovators’ benefits will be outweighed by costs when they are copied. This critique also poses a serious threat to the hypothesis that play is a driver in the evolution of innovative object use. Specifically, object play does seem to represent a considerable cost to the extent that it represents between 18% and 30% of children’s time budgets in preschool classrooms (McGrew, Reference McGrew1972; Pellegrini & Gustafson, Reference Pellegrini, Gustafson, Pellegrini and Smith2005; Pellegrini & Hou, Reference Pellegrini and Hou2011). With this said, the figure is limited to university preschools where the ethos is to stimulate children’s play in object-rich environments (Smith, Reference Smith and Pellegrini1988). To get a fuller picture of the actual time budgets of children’s object play, they need to be studied in the niches they spend most of their time: home and community.
Even if we assume that object play is costly and that others observe and copy innovative object play, there are indeed costs for ‘copiers’, as with all social learners. This is because they would have to spend a relatively large amount of time to observe few innovative behaviours, since innovations with objects are typically rare (Fagen, Reference Fagen1981) and, when they occur, are preceded by long periods of experimentation (Huffman & Quiatt, Reference Huffman and Quiatt1986). Further, the innovators may still accrue net benefits from their behaviours being copied if the copiers reciprocate and cooperate with the initiator. Relative costs of innovation will outweigh benefits if ‘freeloaders’ can use the innovations for their own ends. However, and following the principles of mutualism (Clutton-Brock, Reference Clutton-Brock2009), individuals’ costly behaviours (e.g., the innovative players) can be attenuated if individuals benefiting from those behaviours (the copiers) reciprocate with beneficial behaviours. This becomes a very plausible hypothesis when we consider that young children are most likely to interact repeatedly with others who share interests in similar activities and that these shared interests are the basis for ‘friendship’ in childhood. Correspondingly and in the course of these activities, friends are also more likely to be reciprocal and share information with each other (Gottman, Reference Gottman1983). Indeed, children’s early altruistic acts are first observed in the context of friends interacting with each other (Kanfer et al., Reference Kanfer, Stifter and Morris1981). While these claims are supposition, they are based on sound theory and supporting data, and experimentally testable or testable through theoretical modelling.
Conclusions
In this chapter I have discussed children’s uses of objects and presented descriptive data on their uses of objects in exploration, play with objects, construction, and tool use. The distinction among these categories is an important one as, to my knowledge, they have not been frequently differentiated in the child development literature on children’s play. First, these categories are distinct, and they should be treated as such, as they have different developmental histories and different implications for using objects to solve problems. Correspondingly, scholars should take care to use labels consistently. With all of this said, much more work is needed, particularly observational work documenting the time spent in different sorts of object use. This advice is in the tradition where science should involve both inductive and deductive processes.
This review suggests that children in the industrialized world spend from moderate to substantial portions of their days in different types of object use. With this level of investment, there should be some pay-off for children. There is reasonable agreement among students of play from a wide variety of scholarly disciplines that the pay-off should relate to children’s behavioural flexibility. The search for functions of object uses has been elusive, however, in both the experimental and naturalistic literatures. I posit that the behavioural flexibility associated with object play is indeed important, but not for solving contrived problems. Instead, object play and its associated behavioural flexibility probably serves as a model for other children, who, in turn, emulate and imitate these behaviours. By these means, new behavioural strategies can spread through the population.
It should also be apparent from the discussion in this chapter that much more attention needs to be paid to the social context in which children use objects. Future research should attempt to replicate the relation between object play and behavioural flexibility and attention structure. Further, studies using variations on diffusion chains should test this hypothesis experimentally.
