This review examines research and theory pertaining to the relation between social-cognitive development and toys. Empirical research establishes a moderate relation between the availability of toys and children’s development throughout early childhood, a relation that appears to reflect more than an association with social status. The relation appears bidirectional and varies somewhat according to sex and race. Several aspects of psychological theory appear to describe part of the relation between social-cognitive development and use of toys. These include cognitive developmental theory (Piaget), theory relating learning and development (Vygotsky and Feuerstein), script theory (Bretherton), theories of intrinsic motivation (Berlyne, Bruner, and Yarrow), and theories relating play to development (Mueller and Dunn).
The importance of the social environment for children’s develop- ment is widely acknowledged. A rich literature exists describing the relation between cognitive, social, and emotional functioning and various aspects of the social environment. Much less is known about attributes of the physical environment and their relation to children’s develop- ment. The purpose of this review is to focus on one aspect of the relation between the physical environment and development in children: the relation between play materials and social-cognitive development. The review consists of two parts: (1) a summary of literature that demonstrates the association between play materials and social-cognitive development during childhood; and (2) an examination of several theoretical perspectives that may help to explain the connection between play materials and development.
Perhaps the most intensive home observational studies of the relation between the presence of toys and materials during the first two years of life and children’s cognitive development have been those done by Wachs and his colleagues (Wachs, 1976, 1978; Wachs, Uzgiris, & Hunt, 1971). The first study involved 102 predominantly lower-class children. Observations in the homes of these children revealed that the
availability of books and toys during the second year of life was significantly correlated with scores from the Infant Psychological Development Scale at 22 months, but not at 15 or 18 months. Research done on a second sample of 39 children showed a substantial relationship between the number of audiovisually responsive toys and children’s performance on object permanence and the development of schemas throughout the second year of life and .6 with IQ at age 30 months.
Clarke-Stewart (1973) did repeated observations of 36 predom- inantly low SES children and their mothers in home and laboratory settings and assessments of infant competence throughout the period of 9 to 18 months. By age 17 months, children spent an average of 34% of their time interacting with their mothers and about 50% of their time playing with, looking at, and investigating objects (about 20% with toys and 30% with other household objects). Clarke-Stewart observed a correlation of .39 between the number of toys available to the child in the home and a conglomerate measure of competence. Variety of toys was correlated .34 with the competence measure, while the child’s actual use of toys and objects was correlated .46. The variety of toys was correlated .47 with Bayley Mental Development Index at 17 months; and the use of toys and objects was correlated .36.
There is also evidence that the availability of toys during infancy is related to later competency. For example, Tulkin and Covitz (1975) found that the number of environmental objects available at age 2 was correlated .40 with middle-class girls’ performance on the Illinois Test of Psycholinguistic Abilities (ITPA) at age 6 but not to their Peabody Picture Vocabulary Scores (PPVT). For working class girls, the correlations were .55 with ITPA and .40 with PPVT. Moore (1968) found that the toys, books, and experiences present in London children’s homes at age 30 months was correlated .4 and .3 with IQ at age 3 for boys and girls, respectively. Even with social class partialled out, the correlations remained .36 and .14 for boys and girls, respectively. When Moore examined correlations between the age 30 month home
environment scores and IQ at age 8, he observed a .6 correlation for both sexes (about .45 with social class partialled out).
Barnard, Bee, and Hammond (1984) investigated 163 working class and middle-class families from the Seattle area. Correlations between the number of play materials scores and cognitive competence during the first 4 years of life were low but significant (.2 to .4). Correlations for children of well-educated mothers were low (.2 to .3). Those for mothers with less than a high school education were a little higher (.3 to .4). Correlations were clearly higher for boys (.3 to .5) than for girls (.2 to .3). When maternal education and SES were partialled out of the correlation between play materials and intellectual competence, some attenuation was noted but the partial correlations remained significant (.2 to .3).
Fewer studies on the relation of play materials and social-cognitive development during the preschool period have been reported. However, as the research by Siegel (1984) demonstrates, the same general pattern appears to hold. She found that the availability of play materials at age 3 showed low to moderate correlations (.3 to .5) with 3-year Stanford- Binet and Reynell Language scores. Five-year scores on play materials were correlated .5 with scores on the McCarthy General Cognitive Index. Ware and Garber (1972) found that the availability of materials for learning in the home correlated about .3 with scores on the Preschool Inventory for Mexican-American and black American 4-year-olds. A study comparing children with language impairments (Down syndrome), children with language delays (no apparent organic basis for the developmental problem), and children with normal language skills showed that the amount and appropriateness of toys during the preschool years significantly differentiated the homes of language delayed and normal groups (Wulbert, Inglis, Kriegsman, & Mills, 1975).
An especially revealing longitudinal study of older (ages 8 to 14) handicapped children was conducted by Nihira and his colleagues (Nihira, Meyers, & Mink, 1980, 1983). It involved 114 trainable mentally retarded children (mean IQ = 42.4, SD = 9.9) from southern California who were living at home. The home environments of the children were assessed with a variety of measures including the HOME Inventory and the Home Quality Rating Scale. Children were assessed by the Adaptive Behavior Scale and parental ratings of social and psychological ad- justment. Children’s social adjustment was significantly related to the amount of stimulation through toys and equipment.
The Little Rock Longitudinal Study
During the past two decades we have been involved in a research study that has particular relevance for the topic of this report, the Longitudinal Observation and Intervention Study (Caldwell, Elardo, & Elardo, 1972). This study commenced in 1970 and involved approx- imately 130 children. Approximately 60% of the participants were black, and 40% were white. As Table 1 shows, the availability of appropriate play materials from infancy through preschool was moderately correlated (.4 to .6) to mental test scores from age 3 to age 8 (Bradley & Caldwell, 1976, 1984; Elardo, Bradley, & Caldwell, 1975).
A primary concern of ours was whether the observed relation between the availability of play materials early in life and later mental test scores occurs because of the correlation between early environ- mental opportunities and later environmental opportunities or because of the particular salience of play materials during the first year of life. The findings for females suggested that the observed correlation between play materials and IQ results because of a stable pattern of environmental opportunities. For males, there was evidence that play materials available during the first year or so of life may have some unique value. For whites, the set of partial correlations indicated that scores on play materials at all three time points contributed about the same to 3-year IQ (.2 to .3). For blacks, later scores on play materials were more predictive than earlier scores.
A second issue we addressed was whether the observed relation between the availability of toys in the first year of life and later IQ might reflect overall differences in the home rather than the availability of play materials per se. Findings suggested that the mere availability of toys may not be sufficient for facilitating intellectual development. Specifically, play materials was significantly correlated with maternal involvement (.61 to .75). Thus, it may be that availability of appropriate play materials, in conjunction with consistent encouragement, may be useful for development.
A third area of focus for our studies was bidirectionality of effect. Cross-lagged panel analyses indicated that the primary direction of effect in the period from 6 to 12 months may be from child to environment (i.e., more capable children elicit more appropriate play materials from their parents). However, in the period from 12 to 24 months, the effects seem about equal in both directions.
A final study utilizing the Little Rock longitudinal sample examined
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the relation between HOME subscale scores and family demographics when infants were 1 and 2 years old. This study was done to determine the extent to which the environmental processes tapped by the HOME might be attributable to common socioeconomic, family structure, and racial characteristics. For both time points, scores on play materials showed only modest correlations with demographic variables. Also, they were more strongly related to family structure as compared to social status characteristics. In sum, while part of the relation between play materials and social-cognitive development may be attributable to the relation with social status, most of the relationship does not seem attributable to such associations.
Play Materials and Social-Cognitive Development
While empirical research clearly establishes a link between a child’s encounters with toys and social-cognitive development, no attempt has been made to articulate a coherent, comprehensive set of theoretical propositions concerning the relationship. It is beyond the scope of this article to delineate such a set of propositions. However, an attempt will be made to briefly describe several theories and models that may serve as a partial basis for generating hypothetical patterns of relationship. They are reviewed for their heuristic value in clarifying the role and function of toys in early development. To this end, three major categories of theory are explored: theories dealing with normal cognitive develop- ment in early childhood, theories of intrinsic motivation, and theories concerning the role of play.
Theories of Social-Cognitive Development
One of the most obvious sources for ideas regarding the link between play materials and social-cognitive development is Piagetian theory. Since Piagetian theory is generally well known in education, only a few summary comments will be made concerning its potential relevance. To wit, Piaget conceived cognitive development as a dynamic activity whereby a person encounters new stimuli and, through the complementary processes of assimilation and accommodation, restruc- tures his or her current way of understanding. During the period from infancy through adolescence, a person’s ability to conceive events and ideas advances through four distinct stages. Upon reaching the fourth
stage, formal operations, a person can consider purely abstract ideas and propositions. In early childhood, however, when a child is in the sensorimotor and preoperational stages of development, the ability to comprehend experiences is highly dependent on having an opportunity to directly observe and act upon concrete events and objects. In these stages, the availability of a wide variety of toys and other physical objects that may be explored and manipulated increases the likelihood of a child’s developing differentiated concepts.
A contemporary of Piaget’s, the Russian psychologist Lev Vygotsky, articulated a theory of learning and development which may have particularly useful implications concerning the value of play materials. Vygotsky was interested in the practical intelligence of infants. His observations suggested that intellectual development was determined &dquo;both by the child’s degree of organic development and by his or her degree of mastery in the use of tools&dquo; (1978, p. 21).
According to Vygotsky, a dialectical unity of tool and symbol systems evolves in children-beginning in the second year of life. Speech joins forces with eye and hand in the solution of practical problems. Vygotsky argued that the convergence of these two systems in early childhood is the single most significant event in the history of intellectual development. In this context, it is important to clarify that Vygotsky does not use the word tool synonymously with the word object (or obviously, the words play materials). Tool refers to the indirect function of an object to accomplish some activity. That is, tools are used to mediate activity. As mediators of activity they arc linked to higher intellectual functioning. Two things must be present in order for the marriage of tool and symbol systems to become productive: (1) normal opportunities for the language system itself to develop; and (2) a varied, responsive, and manipulatable object environment. Thus, during the first 3 years of life, play materials and other responsive physical objects provide an arena of opportunities for intellectual development.
Vygotsky proposed that a dynamic, interdependent relationship ‘
exists between learning and development in humans. To explain this relationship he introduced the concept of the zone of proximal development (ZPD). According to Vygotsky (1978), the ZPD is the &dquo;distance between the actual developmental level as determined by independent problem solving and the level of potential development as determined through problem solving under adult guidance or in collaboration with more capable peers&dquo; (p. 86).
With respect to preschool children, Vygotsky felt that play settings afforded a particularly rich environment for the creation of zones of
proximal development. The potential value of play settings (and for play materials used in play settings) in enhancing social-cognitive develop- ment can perhaps best be understood in terms of Vygotsky’s ideas on the relation of actions and objects to meaning. Early in life objects dominate meaning and action. Children’s behavior is impelled by things and their understanding is driven by inherent features of those things. With advances in cognitive capability, the field of meaning is separated from the field of perception. Then children can use things imaginatively in the service of their motives. The play setting determines the meaning of the object. The tree branch becomes the magic wand. In play, toys and other objects become pivots detaching the meaning of words from the real objects they designate (e.g., in pretending that a stickhorse is a horse, the word &dquo;horse&dquo; is no longer isomorphic with the real animal it designates). At this point in development, play materials and other objects become vehicles for transporting meaning from real objects and, thereby, for facilitating social-cognitive competence. Thus, the role of toys in play is different from that in infant action. They do not so much dominate as they assist in the development of new meaning. They help to carry out the wishes, intentions, and motivations of the child as they operate in imagination. In essence, play materials and actions provide a channel through which meaning is realized and motivations fulfilled. &dquo;From the point of view of development, creating an imaginary situation can be regarded as a means of developing abstract thought&dquo; (Vygotsky, 1978, p. 103).
While Vygotsky’s ideas have had little direct impact on North American psychology and education, his ideas have had indirect influence, first through his student, Luria, and most recently through the Israeli psychologist, Feuerstein (1979). Feuerstein’s approach to assess- ment and programming for mentally retarded children, the Learning Potential Assessment Device, borrows directly from Vygotsky’s concept of the zone of proximal development. However, Feuerstein expands the ideas derived from Vygotsky and Luria in ways that may have particular relevance for part of the relation between play materials and social- cognitive development.
According to Feuerstein (1979), many of the cognitive impairments manifest in children do not emerge from poor genetic endownment or organic deficiencies. Rather, they emerge because of insufficient mediated learning experiences.
Mediated learning experience … is defined as the inter- actional processes between the developing human organism
and an experienced, intentioned adult who, by interposing himself between the child and the external sources of
stimulation, &dquo;mediates&dquo; the world to the child by framing, selecting, focusing, and feeding back environmental ex- periences in such a way as to produce in him appropriate learning sets and habits … Mediated learning, as opposed to direct exposure learning, does not depend on chance con- frontation with objects but on the impact of the adult’s intervention in making the child focus on and/or manipulate them … Over and above the specific contents the child might obtain by means of mediation is an attitude toward thinking and problem solving that is actively and efficiently involved in organizing the world of stimuli impinging on the individual from both internal and external sources. (pp. 71-72) Feuerstein (1979) does not speak directly concerning the avail-
ability and use of play materials for young children. However, part of providing sufficient mediated learning experiences for children generally entails careful selection and guided use of physical objects-more clearly dealt with in Feuerstein’s suggestions concerning curricula for mentally retarded children.
Theories of Instrinsic Motivation
Both Vygotsky (1978) and Feuerstein (1979) recognized the importance of children’s motivation in the learning process. For Vygotsky, in particular, objects have a compelling quality for young children. The notion of a compelling quality in objects is more fully articulated in theories of intrinsic motivation. Bruner (1972, 1973) has argued that among humans there are three instrinsic motives: curiosity, competence (mastery), and affiliation. The first two have rather straightforward applications to the relation between toys and social- cognitive development. The connection with affiliation is more in- direct.
Berlyne (1960, 1965) contends that stimulus properties such as novelty, surprise, complexity, and incongruity can produce conflict and, thereby, increase arousal. In essence, objects and situations that manifest these properties induce exploratory behavior. They impel a person to seek information in order to reduce felt uncertainty. Gottfried (1984), in her recent review of literature that treats the application of motivation
research on the relation between play materials and early development, argues that there
is ample evidence, from infancy through early childhood, that children attend more to stimuli with collative properties than to familiar stimuli. These stimulus properties have included novelty, complexity, and incongruity … It has also been found that toys characterized by novelty (Mendel, 1965) and complexity (Ellis, 1984; McCall, 1974) are preferred, or played with more, by children. (p. 4)
She goes on to conclude that play materials with these collative properties &dquo;increase arousal and therefore create curiosity, enhance attention, facilitate cognitive processing, and maintain persistence&dquo; (pp. 4-5).
The second intrinsic motive that has a direct bearing on the relationship between the availability of toys and children’s social- cognitive development is mastery (i.e., the desire to experience effectance for its own sake). A feeling of effectance results when a person engages in challenging experiences (Harter, 1978). According to Gottfried (1984), &dquo;A central theme pervading the mastery view of intrinsic motivation is the concept that the child experiences him/herself as a causal agent of outcomes in the environment&dquo; (p. 7). The perception of oneself as having the power to control outcomes results in an immediate sense of pleasure and a longer term sense of self-worth. An association between mastery motivation and early cognitive development has also been demonstrated by Yarrow and his colleagues (Yarrow, MacTurk, et al., 1984; Yarrow, McQuiston, et al., 1983; Yarrow, Morgan, Jennings, Harmon, & Gaiter, 1982).
There is also a growing body of evidence which suggests that mastery motivation is facilitated by the availability of a stimulating, responsive environment. For example, Yarrow et al. (1982) found that responsive feedback from toys was significantly related to persistence in play behaviors in 6-month-old infants. Belsky, Garduque, and Hrncir (1984) also found that the highest spontaneous level of free play among 12- to 18-month-old infants was related to the availability of a responsive home environment. From her review of the mastery motivation
literature, Gottfried (1984) concluded, &dquo;Responsivity of play materials appears to be a consistent finding related to mastery motivation in play from infancy through childhood&dquo; (p. 11). In sum, mastery motivation, with its concomitant positive effects on social and cognitive develop-
ment, appears to be facilitated by objects and experiences that provide challenge and permit control.
The third intrinsic motive that appears connected to the relation between toys and social-cognitive development is affiliation, the inherent desire of humans to interact with other humans. That connection is perhaps best understood in the context of play.
Play and Social-Cognitive Development
The function of toys in social play contexts can be seen in the cross- systems model of Mueller and his colleagues (Mueller, 1979; Mueller & Brenner, 1977; Mueller & Rich, 1976; Mueller & Vandell, 1979). Their observational studies of toddler peer groups emphasizes the importance of toys and other play objects in the social structure. According to Mueller (1979), emerging social structure among toddler peer groups
does not depend on peer-related skills; instead it relies on the toddler’s attachment to toys and skill with toys. From the
start, toddlers find themselves coming together because they share skills for things like opening the jack-in-the-box or sliding down the slide. (p. 174). The research of Mueller and his colleagues revealed that play
materials function as a contextual basis of toddler social interaction. In
fact, up to the age of 2 years, 83% of all social interactions involved physical objects. Toddlers &dquo;are drawn into contact by the reciprocal interest in physical things. They initiate each other’s toy play and gradually learn to control each other and not only the toy&dquo; (Mueller, 1979, p. 188).
Mueller (1979) summarized the research by reference to the cross- systems model of early social development, which posits that both a cognitive structure and a social structure are operative in social development. Cognitive growth is seen as evolving from structured social interactions. &dquo;The interactions change the child, and after several children have changed in similar ways, new forms of social structure are created; these in turn foster further cognitive change&dquo; (p. 15).
In sum, part of the connection between play materials and social- cognitive development may be their joint relation to social interaction (with both peers and adults). Playthings and other physical objects form the basis for purposive encounters which themselves involve learning,
but which also lead to further development in both cognitive and social domains. Within the context of play, toys may lead to the development of physical and social skills together with imaginative reconstruction of ideas and social relations.
Bretherton (1984) has attempted to link symbolic play to social- cognitive development using the framework of script theory. Script theory maintains that young children organize information in terms of &dquo;scripts&dquo; or &dquo;stories&dquo; rather than in terms of concepts arranged hierarchically from greater to lesser inclusiveness. Script theory repre- sents a significant evolutionary step from traditional Piegetian theory. It gives a more central role to figurative representation in cognitive development; and it more clearly links cognitive and social development. Script theory postulates that at the most basic level, representation in young children is organized in terms of event schemata that are skeletal frameworks of everyday events. Bretherton (1984) states,
These frameworks are figurative in that they represent spatio- temporo-causal links among agents, recipients, and objects and are in this sense isomorphic with reality. They are constructed and revised in the course of repeated experiences with similar events, but they in turn guide understanding of such events. (p. 5)
Evidence suggests that these scripts or event schemata may constitute first-order organization from which other cognitive structures or processes (such as taxonomic hierarchies, roles, and problem-solving strategies) are then derived (Nelson, 1981).
The importance of toys and other play materials to event representation is clearly presented by Bretherton (1984):
Pretending simulates and tranforms routine events from family life, story books, and television. However, the ability to represent these scripts … does not emerge fully fledged. With development, there is a marked increase in the number of roles and the order and coherence of action repro- duced … accompanied by a decreasing reliance on veridical props … Role, action, and object representation are here treated as separate dimensions of pretend play even though, at the simplest level, they are not completely dissociable. An action always requires an agent and frequently an ob- ject… Role and action representation are initially affected by the availability of realistic props. Later, objects can be
mentally transformed into other objects and imaginary props can be created through miming or language. (p. 8) For infants the value of objects in creating scripts is considerable.
Their first efforts at pretending appear to require prototypical physical objects (e.g., dolls, utensils, telephones, cars). Very gradually the need for realistic objects to support pretense lessens. However, Fenson and Ramsey’s (1981) observational research shows that children rarely engage in empty-handed miming prior to the middle of the third year of life. Bretherton (1984) concludes that the presence of realistic objects
seems to provide perceptual-tactile-spatial support for the performance of the first miniscripts like sleeping or eating. Without such support, 12-month-olds are unlikely to engage in pretending at all. Later in the second year, children begin to substitute one object for another. (p. 19)
With advancing age, the ability to substitute objects increases. Bretherton (1984) offered one final comment concerning the role
of objects such as toys in social-cognitive development in pretend play:
Although play with nonveridical objects and miming become more common with age, realistic objects continue to play an important role. In a study of collaborative pretending, Garvey and Berndt (1977) found that the presence of a realistic prop often led to the instantiation of a related script (their term is action scheme). (p. 22)
Dunn (1984), in her studies of toddlers from the United Kingdom, has carefully examined play as an arena for social-cognitive development. She found that parental involvement change both the nature and duration of time children spent in play activities:
The data from each of the studies suggests that the mothers’ involvement was frequently didactic in nature: the mothers used the context of joint pretend play to explore the concepts of size and shape, to encourage classificatory skills, and especially to discuss the function and appropriate use of objects. (p. 8)
Beyond their role as teachers, mothers also tended to use play settings as situations in which to discuss inner feelings and states with the child. Dunn (1984) concluded that
joint pretend play between mother and child offers an opportunity for a variety of social learning experiences, and that it provides a context in which mothers’ speech is not only specifically didactic but is rich in those features of extension and acknowledgement that studies of language acquisition have emphasized as potentially valuable. (p. 13)
Summary and Conclusions
In sum, the literature linking the use of play materials and children’s s social-cognitive development is very sketchy. It provides only general clues regarding the relationship. The dearth of information notwith- standing, the following conclusions and functional-sequential model are offered concerning the relationship. They are offered for their heuristic value in generating research that may more fully delineate the relationship.
Summary Propositions 1. If given the opportunity, young children tend to spend a con-
siderable amount of time viewing and interacting with toys and other objects.
2. The availability of a variety of responsive toys is related to social- cognitive development throughout early childhood.
3. The association between play materials and development is partially a function of parental education and socioeconomic status, but is not solely a reflection of these influences.
4. The relationship between toys and development is bidirectional. More competent children tend to seek out a greater variety of appropriate play objects; appropriate play objects assist develop- ment.
5. Intrinsic motives of curiosity and mastery impel a child to explore and manipulate interesting toys and objects, thus providing an arena for learning.
6. Children’s interest in toys leads them to social encounters with peers and adults; these are rich in cognitive and social learning oppor- tunities.
7. Play materials sometimes act as catalysts for adult-child interactions
(particularly mediated learning experiences) that help shape and support social-cognitive development.
8. Cognitive development in very young children is highly dependent on direct encounters with objects (including toys).
9. Toys and other realistic objects become useful hooks for the construction of spatio-temporo-causal scripts that characterize the infancy and preschool period.
10. As children become capable of representational thinking, objects are often used as pivots through which children transfer meaning from real objects in pretend play.
11. Toys sometimes serve as catalysts for imaginative play. They can serve to carry the meaning of the play situation to full realization. They may also help provide a link between learning derived from the imaginative world of play and the more concrete settings of the real world.
The schematic found in Figure 1 depicts a set of functional- sequential relationships linking the use of toys to social-cognitive development. It does not represent a causal chain. Rather, it is designed to show a variety of ways in which play materials may serve as the beginning point in a sequence of actions that result in enhanced social- cognitive development. It is an heuristic model. No assumption is made that the sequence of events occurs exactly as depicted in all instances or that there are not other patterns of relationships linking toys to development. However, the model offers a potentially useful framework from which to plan research on play materials and to organize certain parent education activities.
In closing, two caveats are offered. First, current knowledge of both normal and delayed development indicates that it is a complex, multiply determined process. Thus, predictions about the role of play materials for specific individuals are subject to a high degree of uncertainty. Second, the purpose of this article was to discuss ways that play materials might serve to enhance social-cognitive development. While it is assumed that toys generally have an impact on development that ranges from neutral to positive, it is almost certain that their impact is occasionally negative. They can, for example, cause frustration when too difficult to operate; they can distract or interfere with a more
Figure 1. Interrelated functional-sequential transactions involving play materials and social-cognitive development.
productive learning process; they can be the occasion of negative social encounters; and they can limit the use of imagination. In the long run, if a model relating play materials to development is to be maximally useful, it will have to include potentially negative as well as positive sequences.
Barnard, K., Bee, H., & Hammond, M. (1984). Home environment and cognitive development in a healthy, low-risk sample: The Seattle study. In A. Gottfried (Ed.), Home environment and early cognitive development (pp. 117-150). New York: Academic Press.
Belsky, J., Garduque, L., & Hrncir, E. (1984). Assessing performance, competence, and executive capacity in infant play: Relationships to home environment and security of attachment. Developmental Psychology, 20, 406-417.
Berlyne, D. (1960). Conflict, arousal, and curiosity. New York: McGraw-Hill. Berlyne, D. (1965) Curiosity and education. In J. Krumholtz (Ed.), Learning and the
education process (pp. 67-89). Chicago: Rand McNally. Bradley, R., & Caldwell, B. (1976). The relation of infants’ home environments to
mental test performance at fifty-four months: A follow-up study. Child Develop- ment, 47, 1172-1174.
Bradley, R., & Caldwell, B. (1984). The relation of infants’ home environments to achievement test performance in first grade: A follow-up study. Child Development, 55, 803-809.
Bretherton, I. (1984). Representing the social world in symbolic play: Reality and fantasy. In I. Bretherton (Ed.), Symbolic play: The development of social understanding (pp. 3-41). New York: Academic Press.
Bruner, J. (1972). The nature and uses of immaturity. American Psychologist, 27, 687- 708.
Bruner, J. (1973). Organization of early skilled action. Child Development, 44, 1-11. Caldwell, B., Elardo, P., & Elardo, R. (1972). The longitudinal observation and intervention
study. Paper presented at the Southeastern Conference on Human Development, Williamsburg, VA.
Clarke-Stewart, K. (1973). Interactions between mothers and their young children: Characteristics and consequences. Monographs of the Society for Research in Child Development, 8.
DeStafano, C. (1979). Environmental determinants of peer social behavior and interaction in a toddler play group. Unpublished docoral dissertation, Boston University.
Dunn, J. (1984). Pretend play in the family. Paper presented at the Johnson and Johnson Pediatric Roundtable No. 11. Key Biscayne, FL.
Elardo, R., Bradley, R., & Caldwell, B. (1975). The relation of infant’s home environments to mental test performance from six to thirty-six months: A longitudinal analysis. Child Development, 46, 71-76.
Ellis, N. (1984). Play, novelty, and stimulus seeking. In T. Yawkey & A. Pellegrini (Eds.), Child’s play: Developmental and applied (pp. 203-218). Hillsdale, NJ: Erlbaum.
Fenson, L., & Ramsey, D. (1981). Effects of modeling action sequences on the play of twelve-, fifteen-, and nineteen-month old children. Child Development, 52, 1028- 1036.
Feuerstein, R. (1979). The dynamic assessment of retarded performers: The learning potential assessment device, theory, instruments and techniques. Baltimore: University Park Press.
Garvey, C., & Berndt, R. (1977). Organization of pretend play. JSAS Catalog of Selected Documents in Psychology, Z (Ms. No. 1589).
Gottfried, A. (1984). Intrinsic motivational aspects of play experiences and play materials. Paper presented at the Johnson and Johnson Pediatric Roundtable No. 11. Key Biscayne, FL.
Harter, S. (1978). Effectance motivation reconsidered: Toward a developmental model. Human Development, 21, 34-64.
McCall, R. (1974). Exploratory manipulation and play in the human infant. Monographs of the Society for Research in Child Development, 39 (2, Serial No. 155).
Mendel, G. (1965). Children’s preferences for differing degrees of novelty. Child Development, 36, 453-465.
Moore, T. (1968). Language and intelligence: A longitudinal study of the first eight years, Part II. Environmental correlates of mental growth. Human Development, 11, 1-24.
Mueller, E. (1979). (Toddlers + Toys) = (An autonomous social system). In M. Lewis & L. Rosenblum (Eds.), The child and its family. New York: Plenum.
Mueller, E., & Brenner, J. (1977). The origins of social skills and interaction among play group toddlers. Child Development, 48, 854-861.
Mueller, E., & Rich, A. (1976). Clustering and socially-directed behavior in a play group of 1-year-olds. Journal of Child Psychology and Psychiatry, 17, 315-322.
Mueller, E., & Vandell, D. (1979). Infant-infant interaction: A review. In J. Osofsky (Ed.), Handbook of infant development. New York: Wiley-Interscience.
Nelson, K. (1981). Social cognition in a script framework. In J. Flavell & L. Ross (Eds.), Social cognitive development. Cambridge: Cambridge University Press.
Nihira, K., Meyers, E., & Mink, I. (1980). Home environment, family adjustment and development of mentally retarded children. Applied Research in Mental Retardation, 1, 5-24.
Nihira, K., Meyers, E., & Mink, I. (1983). Reciprocal relationship between home environment and development of TMR adolescents. American Journal of Mental Deficiency, 88, 139-149.
Siegel, L. (1984). Home environment influences on cognitive development in pre-term and full-term children during the first 5 years. In A. Gottfried (Ed.), Home environment and early cognitive development (pp. 197-234). New York: Academic Press.
Tulkin, S., & Covitz, F. (1975). Mother-infant interaction and intellectual functioning at age six. Paper presented at the biennial meeting of the Society for Research in Child Development. Denver, CO.
Vygotsky, L. (1978). Mind in society (M. Cole, V. John-Steiner, S. Scribner & E. Souberman, Eds.). Cambridge, MA: Harvard University Press.
Wachs, T. (1976). Utilization of a Piagetian approach in the investigation of early experience effects: A research strategy and some illustrative data. Merrill-Palmer Quarterly, 22, 11-29.
Wachs, T. (1978). The relationship of infants’ physical environment to their Binet performance at 2½ years. International Journal of Behavioral Development, 1, 51-65.
Wachs, T. Uzgiris, I., & Hunt, J. (1971). Cognitive development in infants from different age levels and different environmental backgrounds: An explanatory investigation. Merrill-Palmer Quarterly, 17, 283-317.
Ware, W., & Garber, M. (1972). The home environment as a predictor of school achievement. Theory into Practice, 11, 190-195.
Wulbert, M., Inglis, S., Kriegsman, E., & Mills, B. (1975). Language delay and associated mother-child interactions. Developmental Psychology, 11, 61-70
Yarrow, L., MacTurk, R., Vietze, P., McCarthy, M., Klein, R., & McQuiston, S. (1984). Developmental course of parental stimulation and its relationship to mastery motivation during infancy. Developmental Psychology, 20, 492-503.
Yarrow, L., McQuiston, S., MacTurk, R., McCarthy, M., Klein, R., & Vietze, P. (1983). Assessment of mastery motivation during the first year of life: Contemporaneous and cross-age relationships. Developmental Psychology, 19, 159-171.
Yarrow, L., Morgan, G., Jennings, K., Harmon, R., & Gaiter, J. (1982). Infants’ persistence at tasks: Relationships to cognitive functioning and early experience. Infant Behavior and Development, 5, 131-141.