The ecological approach to perceiving as a foundation for understanding the development of knowing in infancy

DEVELOPMENTAL

REVIEW

3, 371-404 (1983)

The Ecological Approach to Perceiving as a Foundation for Understanding the Development of Knowing in Infancy EUGENE The Children’s

C. GOLDFIELD

Hospital

Medical

Center, Boston

The ecological thesis of direct realism is used as a framework for examining the development of knowing in human infancy. When information for perceiving is defined ecologically (i.e., relative to the situational context and to the physical dimensions, capabilities, and needs of the perceiver), knowing need not be construed as the act of using representations to give meaning to acts or percepts. Knowing, alternatively, is the act of noticing affordances, situation and perceiverspecific meanings of objects, according to their value to the perceiver for achieving specific goals. Changes with development in infant sensorimotor functioning may, in this view, be explained by a process of increasing economy in noticing potentially available affordances, rather than a process of constructing a representational system for making present something not present. Studies of three infant skills widely attributed to the onset of representation are examined with regard to this ecological thesis. Results indicate that the noticing of affordantes is critically involved in each of these skills.

The ecological approach to perceiving (Gibson, 1966, 1979; Shaw, Turvey, & Mace, 1982) provides a unique perspective on the nature of knowing. Psychologists have only recently directed their attention to the implications of this approach for human cognitive and social development (Shotter & Newson, 1982; Wilcox & Katz, 1981). At the heart of the ecological approach is the view that an observer-scaled description of information availabile to a perceiver/performer, uffordances (Gibson, 1977), obviates the necessity for a representational function which interprets the meaning of perceiving and acting. This paper adopts the ecological approach to perceiving in an attempt to provide a new perspective on the development of knowing in infancy, a topic which has generated considerable controversy (Fischer & Jennings, 1981; Forman, 1982). The major question addressed here is whether knowing is best characterized as the capacity to use representations to give meaning to percepts. It is during infancy that humans are presumed to first develop the capacity for representation and, thus, it is The author thanks Beverly A. Goldtield and Robert M. Hodapp for their assistance during preparation of this article, and William M. Mace and the two anonymous reviewers for their thoughtful comments. Requests for reprints should be sent to Eugene C. Goldtield, Department of Psychiatry, Children’s Hospital Medical Center, 300 Longwood Avenue, Boston, MA 02115. 371 0273-2297/83$3.00 Copyright 0 1983 by Academic hrss, Inc. All rights of rewoductmn in anv form rewrved.

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important to clarify what is developing during this period. The consequence of ignoring this issue is an account of human development with imprecise initial conditions. The first section of this paper provides a brief overview of the foundations of the ecological approach to perceiving: the work of James and Eleanor Gibson and of Shaw et al. (1982). Particular attention is paid to the concepts of affordance and effectivity and to their relevance for the study of infant knowing. Representational realism and direct realism are contrasted in the second section in the context of current models of cognitive development. The third section presents an analysis of data collected by the author and others on three infant skills attributed by representational realists to the onset of the capacity for mental representation. The three infant skills include search for hidden objects, use of objects as tools, and use of objects as both agents and recipients of action. It is asserted from the results of these studies that what is attributed to representation may alternatively be understood as increasing economy in the noticing of affordances. FOUNDATIONS

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The Optic Array

James Gibson spent much of his career rethinking the nature of the information available to animal and human perceiver/performers who evolved in the context of the terrestrial environment. The classical analysis of light to the eye (Turvey, 1975) was that it is a form of radiant energy propagated through empty space (an “air theory”). Gibson (1979) begins his analysis of the nature of the stimulus for perceiving with a “ground theory” analysis of light to the eye: light as ambient. The optical information for visual perceiving is available in the ambient optic array, light which is multiply reflected from opaque surfaces, forming a dense pattern of rays, or visual solid angles, at particular points of observation. Thus, rather than describing light at a molecular grain of analysis as in the air theory, Gibson provides a description of light at a higher order, ecological, grain of analysis. The starting point for visual perception is the patterning of light by the surfaces of the environment. Direct Perception

Because the optic array is a patterning of reflected light, the unique changes and persistent structure of the environment are directly available for the perceiver/performer to pick up. Stated in another way, the optic array is what it is because the environment from which the light has been reflected is what it is. Gibson, thus, argues that perception is direct: there is necessary specificity between changes and persistent structure in the environment and changes and persistent structure in the optic array.

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Evidence for the assertion of necessary specificity between the dynamic structure of the environment and the optic array comes from the ecological study of events. An event, or change over time that results in a disruption of the surface layout (Gibson, 1979), may be classified along two dimensions: the frame of reference for perceiving, and the relative emphasis on persistence or change. Table 1 presents a matrix of six cells formed by three frames of reference-exteroceptive (layout of environment), proprioceptive (position of body parts relative to the body), and exproprioceptive (position of the body relative to the environment), and two types of event structure, information specifying change (transformational invariants) and information specifying persistence over change (structural invariants). Let us briefly consider in each of these cells some of the research that addresses necessary specificity. Exteroceptive information about change is revealed by change of layout (translation, rotation, collision, deformation, and surface disruption of objects), change of color and texture, and change of surface existence (e.g., liquid to gas, biological growth). The optical information for distinguishing among different types of change in the environment consists of particular disturbances of local structure. The translation of an object against a background, for example, is specified by the progressive deletion and accretion of units on one side of a contour (Gibson, 1979). Visual exteroceptive information about persistence of the layout of the environment is also directly specified. A flat terrain, for example, is characterized by a texture gradient in which there are equal amounts of texture for equal amounts of terrain. The terrain is the minimal context in which animals and humans perceive detached objects which are on the ground. Perception, then, is a context-sensitive process. We perceive objects at a distance as the same size as identical near objects (size constancy), for example, because each of the objects occludes equal amounts of surface texture, not because we compare the sizes of the images of TABLE I A CLASSIFICATION OF EVENTS Visual reference frame Exteroceptive Transformational Invariant (Change) Invariant Structural Invariant (Persistence)

Change in position of detached objects (e.g.. accretiondeletion of texture) Persistence of ground plane; persistence of solid substance over transformation

Proprioceptive

Exproprioceptive

Change in position of body parts relative to each other

Change m position of body relative to the environment

Persistence of body parts relative to each other during body movement

Persistence of body structure (e.g.. size) relative to environment during body movement

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the objects on the retina with stored representations of those objects (see Butterworth, 1981, for a further discussion of this point). Let us next consider visual proprioceptive information about the change in position of a part of the body relative to another part. The sight of parts of the body provides visual proprioceptive information about eye orientation. Hay and Pick (1966), for example, found that there is a change in registered eye position when visual proprioceptive information about the trunk and limbs is altered with wedge-prism spectacles. The persistent identity of parts of the body are also directly specified by visual proprioceptive information, as is apparent in prism adaptation experiments (Lee, 1978). Two skills which rely heavily on visual exproprioceptive information about change of the body’s position in the environment are balance control and locomoting. The role of visual exproprioceptive information in controlling balance has been demonstrated in human infants placed inside a “swinging room” with walls suspended just above the floor (Lee & Aronson, 1974). When an infant stood on a stationary platform and the four walls were made to oscillate, the infant was observed to correct his posture and either sway excessively or lose his balance. In a similar fashion, during locomotion, the radial expansion of the optical flow field specifies egolocomotion (Warren, 1979). Finally, there is evidence that visual exproprioceptive information directly specifies the size (persistent structure) of the animal who is locomoting. In a study of stair climbing by humans, Warren (Note 1) reports that when provided with photographs of stairs, adult subjects express preferences for stairs whose riser heights are .26 of their leg length. Thus, their perception of the stairs seems to be scaled to a persistent structural characteristic of their body, their leg length. More on this point is discussed in the next section on affordances. Affordances

Gibson (1977) introduces the concept of affordance as a way of “ecologizing” the environment with respect to the biological structures of particular species of animals. He defines an affordance of anything as “a specific combination of the properties of its substances and surfaces taken with respect to particular animals” (p. 67). Gibson, thus, emphasizes that the description of the environment must always be with reference to a particular perceiver/performer, taking into account its size, form, and capabilities (Mace, 1977). An object affords sitting upon for a human, for example, if the object rests on a rigid surface of support and is itself rigid and flat and is raised approximately to the height of the knees. The same object may be standon-able, climb-on-able, and fall-off-able. Because the affordance of the

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object is defined over the size, form, and capabilities of the perceiver, a chair may afford sitting upon for an adult, but not for a young infant who is too small and unable to sit up by herself. Fowler and Turvey (1978) provide an action-referenced perspective on the nature of affordances by considering the physical forces involved when an actor participates in an event: The affordances of an environment for an actor, as given in the structured environmental media, are the sets of forces (of adaptive significance to them) that the actor can generate in collaboration with the extant forces, and in relation to the environment . . Among the forces that shape the character of an event are gravitational forces, which are extrinsic to the actor, and functional and contact forces, which are generated by the actor’s encounter with the environment. But in addition to these are the forces that enable an actor more directly to regulate the character of an event. They are the forces generated by the actor’s own muscular activity. (p. 18)

To say, for example, that a rigid surface affords locomotion means that during locomotion, the perceiver/performer picks up optical information which specifies the nature of the reactive forces that the surface will provide for walking. An analysis of affordances as reactive forces is used later in this paper with reference to the development of tool use in infants. There have been other attempts antedating Gibson to address the problem of the nature and development of meaning with a unit of analysis that defined meaning relative to the characteristics of the observer, e.g., Lewin’s (1936) concepts of “valence” and “invitation quality” and Werner’s (1948) physiognomic model of perception. Affordances are distinct from these earlier concepts because the affordance of anything does not change as the need of the observer changes. Instead, “whether or not the affordance is perceived or attended will change as the need of the observer changes” (Gibson, 1977, p. 78). A second distinction between affordances and earlier concepts is with respect to the relation between perceiverlperformer and environment. Following the lead of von Uexkull(1934), Werner (1948) and others modeled the relation between perceiver/performer and environment on the Umwelt, a closed unit where subject and object were dovetailed into each other. Werner (1948), for example, postulated that there was in developmentally primitive organizational systems a fusion between the perceiver/performer and the environment. The dynamics of movement of an object were seen as isomorphic and identical to the actions of the observer. It is with respect to the nature of the isomorphism between perceiver/ performer and environment that further distinguishes affordances from earlier concepts. Rather than an isomorphism that includes identity or fusion between actor and environment, affordances are relations in which

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perceiving and acting are enantiomorphic to each other, forming a mirrorlike duality (Shaw & ‘Au-vey, 1981). Duality is distinct relative to other forms of isomorphism such as equality and identity because it lacks the properties of transitivity and reflexivity. A duality is an isomorphism which is defined only by the property of symmetry. More formally, “a duality relation between two structures X and Z is specified by any symmetric rule, operation, or mapping, T, where T applies to map X onto Z and Z onto X” (Shaw & lI.u-vey, 1981, p. 61). An example of a duality, offered by Shaw and ‘Imvey (1981), is the relation between points and lines in projective geometry. Any two nonidentical coplanar points determine or lie on one line, and any two intersecting lines determine, or lie, on one point. A duality holds between these two theorems because it is possible to translate one into the other by interchanging the words point and line. Affordances are informational structures relating perceiving and acting whereby it is possible to translate affordances into their duals, effectivities (discussed below), by interchanging the descriptors of each. For an object to afford a certain meaning for a perceiver/performer, a duality must hold between perceiving and acting on specific occasions. Consider Shaw and II-u-vey’s example of the affordance of a cup for grasping by an infant: We say a cup X affords grasping Y, (or alternatively has the property of graspability), for an agent Z (e.g., a baby), on the occasion 0 (say on the occasion that Z is thirsty or playful) if and only if there exists a duality relation between X and Z on that occasion (i.e., the baby has matured normally to have both the strength and coordinative capabilities to grasp the cup X and that the cup is not too large, heavy or ill-shaped to be grasped by Z). (p. 72)

While the concept of affordance reaffirms the usefulness of the Umwelt as a unit for understanding meaning, it does not imply a fusion between perceiving and acting in the sense of nondifferentiation. An affordance, instead, implies a complementary, mirror-like relation between perceiving and acting. A developmental issue for which the distinction between fusion and complementarity has implication is the relation between the newborn’s perception of the mother and the experience of his own actions. Both Piagetian and psychoanalytic theory (e.g., Mahler, Pine, & Bergman, 1975) assert a fusion at birth between the infant’s perception of the mother and his own actions. Both argue that it is not until around 4 months of age that infants begin to distinguish their own activities from the perceived activities of the mother. And it is not until well into the second year that the process of differentiation is completed. But, as is apparent in Stern’s (in press) recent review of early infant perceptual

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skills, infants are clearly able to distinguish themselves from their mothers in the earliest months of life. It is suggested here that what both Mahler and Piaget are describing clinically can be reconciled with current research on perceptual development by adopting the view that duality, not identity, exists between mother and infant. In this view, development of cognitive and social skills is not a matter of differentiation of perceiving and acting, but rather a process of noticing the affordances of the mother that are complementary to the effectivities of the infant. A preliminary attempt to apply this viewpoint in understanding the development of reciprocity is presented later. Effectivities Given that affordances are informational structures, and that a duality holds between actor and environment, what is the dual complement of an affordance? Shaw and Turvey (1981) and Turvey, Shaw, Reed, and Mace (1981) introduce the concept of effectivity, a goal-directed potentiality, as the dual of an affordance. To clarify what is meant by effectivity, consider first the following schematization of an affordance: A propertied thing X (e.g., a crevice) affords an activity Y (e.g., crawling into) for a propertied thing Z (e.g., a lizard) if and only if certain properties of X (e.g., the spatial extent of the crevice in the horizontal dimension) are dually complemented by certain properties of Z (e.g., the substantial width of the lizard in the horizontal dimension), where dual complementation of properties translates approximately as properties that are related by a symmetrical transformation or duality T such that T(Pl)-+P2 and T(P2)+Pl. (Turvey et al., 1981, p. 261)

The concept of effectivity fashion as follows:

may be schematized in complementary

A propertied thing Z (an organism) can effect activity Y with respect to a propertied thing X (an environmental situation) if and only if certain properties of Z are dually complemented by certain properties of X. (Turvey et al., 1981, p. 261)

In other words, where affordances are effectivities viewed from the perspective of environmental support for acting, effectivities are affordances viewed from the perspective of organismic support for perceiving (Shaw & Tluvey, 1981). Effectivities and their dual complements, affordances, are dispositional properties or potentialities. As such, they are distinguished from occurrent properties, the observable properties of a thing (Ttu-vey et al., 1981). In the earlier example in which a baby grasps a cup, the effectivities for coordinated control of grasping give the baby the potential to perform other activities with the cup such as hitting it, reaching for it, pointing to it, etc. The factors determining which effectivity is selected to achieve a particular goal are discussed in a later section.

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For the notion of effectivity to be more than just a relabeling exercise, it is necessary to demonstrate that the characteristics which distinguish them from other hypothesized potentialities, such as Piagetian schemes, give them greater explanatory power. Two major differences between effectivities and schemes will be discussed here: (1) while effectivities and schemes may both assume a species-specific acquisition sequence, effectivities exhibit the additional characteristic of being sensitive to individual biological and social variations (Johnston & lbrvey, 1980), and (2) while schemes are typically defined over the infant and her behavior toward inanimate objects, effectivities are defined relative to their necessary dual complements, the affordances of the caregiving environment (which includes inanimate objects). To address the first difference, consider the Piagetian account of how schemes are combined, with particular reference to looking schemes (Piaget, 1952). For Piaget, like other general process learning theorists (see Hilgard & Bower, 1975; Johnston, 1981), schemes may be combined by a process (in this case reciprocal assimilation) which assumes an equivalence of associability. That is, looking may be coordinated with any other scheme, such as sucking and grasping, in an equivalent fashion. An ecological account of the coordination of effectivities, alternatively, argues that there are both species-specific and individual biological and social constraints on the coordination of effectivities (Johnston, 1981). According to the ecological approach to human infant knowing being proposed here, an additional constraint on the universal sequence of coordinating looking with other potentialities described by Piaget, is the specific biological characteristics of the infant and the specific caregiving environment. Human infants have differential opportunities for coordinating looking with other potentialities such as reaching and sucking because of individual differences in (a) postural preferences, (b) behavioral states, and (c) the caregiving strategies of the parent. Each of these is discussed in turn. Most newborns lying supine prefer to orient their heads to the right, possibly as a consequence of intrauterine position (Michel, 1983). Significantly, head orientation at birth predicts the hand that will be preferred for reaching later in infancy: infants with a preference to orient their heads to the right prefer to use their right hand for reaching, and infants who prefer to orient their heads leftward, prefer to use their left hand (Michel, 1983). Coryell and Michel (1978) attribute hand preference for reaching to head orientation preference which biases visual experience of the hands, giving one hand an advantage in eye-hand coordination tasks. Thus, the coordination of vision and reaching is constrained by individual variation in head orientation preference.

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Newborns also exhibit individual variability in states of alertness or attention (Wolff, 1966). Individual variations in total daytime sleeping and waking, for example, depend to some extent on the type of feeding, with developmental increases in waking time consistently delayed in breastfed as compared with bottle-fed babies (Wolff, 1973). These individual variations in wakefulness impose specific constraints on the coordination of looking with other activities. Wolff and White (1965) report, for example, that 3- to 4-day-olds pursue by conjugate eye movements more persistently when they are alert and inactive (with body at rest and eyes open and “shiny”) than while waking and active (with diffuse motor activity of the body and eyes open but not shiny). They also pursue with their eyes as well as or better while sucking on a pacifier than during alert inactivity. Thus, the infant’s state constrains visual pursuit and coordination of looking with other activities. Individual differences in parental responsivity also directly influence infant looking. This can be demonstrated in the situation in which a caregiver presents a mask-like appearance to the infant, either as a result of congenital blindness of the caregiver (Brazelton, Tronick, Adamson, Als, & Wise, 1975) or by experimental manipulation (Tronick, Als, & Adamson, 1980). In both instances, the infant averts his eyes and becomes upset. These three constraints on infant looking-postural preferences, behavioral state, and caregiving- must, therefore, be accounted for when attempting to explain the coordination of looking with other potentialities. This brings us to the second difference between an effectivity and a scheme: effectivities are defined relative to their dual complements, the affordances of the caregiving environment. The argument that the effectivities and affordances of caregiver and infant dually complement each other is supported by the necessary specificity that appears to hold between the caregiver’s perception of the behaviors (and potentialities) of the infant and her own caregiving activities. Studies of “scaffolding” in mother-infant games provide evidence that caregivers modify their caregiving activities in response to (a) what the infant actually does, and (b) the infant’s potentiality or effectivity for more advanced behavior. In the games of roll the ball and peek-a-boo, for example (Hodapp, Goldtield, & Boyatzis, in press), caregivers perform specific activities in response to the infant’s perceived level of skill. When the infant is facing away from the mother at the beginning of a game, she turns him around to face her. She then directs his attention to the task by, e.g., holding out her hands in roll the ball or leaning forward and requesting that the child do a “peek-a-boo.” Significantly, mothers perform these behaviors more frequently when they perceive that they

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are needed most by the infant, i.e., once the chlid is returning the ball or beginning to cover and uncover themselves, and less when these behaviors are not relevant to the child’s current level of skill. Caregivers react not only to what the infant actually does, but also to the infant’s potential, or effectivities, for what he will be able to do in the near future. This is most apparent in the caregiver’s creation of temporal “slots” during games (Snow, de Blauw, & Dubber, 1981). During the prelinguistic game of round the garden, for example, the mother initially tickles the infant while she says a verse. As the game progresses, the mother introduces pauses in the verse, just prior to tickling, which heighten the infant’s excitement, and create an opportunity for the infant to take a turn in the game. In these turn-taking activities, mothers not only leave temporal slots and anticipate that they will be filled, they also respond to the infant’s preverbal utterances in a conversational fashion (Snow, 1977). Mothers respond to the burps, yawns, sneezes, coughs, coo vocalizations, smiles, and laughs of the infant by naming what the infant is doing and asking questions as if expecting a reply. To a smile at the mother, for example: “Oh what a nice little smile. Yes, isn’t that nice?” (Snow, 1977, p. 12). The mother, thus, anticipates the infant’s potential for sensorimotor and linguistic acts. It should be emphasized that while there is an actual duality between a skilled caregiver’s noticing of the affordances of the infant for participating in certain activities, the duality is a potential one for the developing infant. It is not until the infant has noticed those potential affordances which are useful for achieving certain goals that the duality between his effectivities and the affordances of the caregiver become realized. Thus, learning is considered here, following the lead of Vygotsky (1978), as a process of moving from potential to actual development (see Goldfield & Hodapp, Note 2, for a further discussion of this point). Games, then, are considered as ecologically defined systems for learning. In sum, both of the characteristics which distinguish effectivities from schemes-sensitivity to individual variation and sensitivity to social context-give the concept of effectivity greater potential explanatory power than the scheme. The specific ways in which these two characteristics lead to differential predictions in hypothesis testing are presented in later sections. TWO FORMS OF REALISM: IMPLICATIONS FOR DEVELOPMENTAL MODELS OF INFANT KNOWING Representational

Realism

Theories which assume that events are represented by internal structures adopt what Shaw et al. (1982) refer to as representational realism. This viewpoint is challenged by the ecological approach to perceiving

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(see Tlnvey et al., 1981) because of two inherent problems: referentiality and intentionality. These are very briefly discussed here, given the length of the arguments. The problem of referentiality results from the assumption that “the object of perception (a representation) corresponds to its reference object by a causal process” and, thus, “requires that physical entities in the world must somehow be coordinated with psychological entities” (Shaw et al., 1982, p. 174). So, for example, the perceiver is assumed to have internal representations, frames or schemas, which interpret perceptual input. The assimilation by a frame or schema of a preliminary description of the proximal stimulus is what makes possible veridical perception of the distal object. But, given this assumption, one is left with the questions of how the first schema is ever selected, and how the representations interface with the world. The problem of intentionality results from the assumption that internal representations as objects of experience are intentional objects. Intentional objects such as “wants” and “beliefs” do not have ordinary existence since an object need not exist when it is imagined. But as Shaw et al. (1982) note, by characterizing representations as intentional in this way, “unicorns and sphinxes become ontologically indistinguishable from horses and lions and hallucinations indistinguishable from perceptual experiences” (p. 178). Representational

Realism in Current Models of Infant Knowing

There are currently two major approaches to the study of infant knowing: organismic and information-processing models (Reese & Overton, 1970). Both models, it is argued, adopt the assumption of representational realism, namely, that one must know one thing before being able to experience another (Shaw & Bransford, 1977). A major consequence of adopting representational realism is the necessity of assuming that perceived events are assimilated to memorial-conceptual schemas which interpret current input in light of past experience. The Piagetian (organismic) model of cognitive development in infants uses the term representation in two senses-broad and narrow. In its broad sense “representation is identical with thought, i.e., with all intelligence which is based on a system of concepts or mental schemes . . . In its narrcw sense, representation is restricted to the mental or memory image, i.e., the symbolic evocation of absent realities” (Piaget, 1951, p. 67). In the former, operative sense, Piaget is referring to representation as a process of transforming and coordinating existing schemas, while in the latter, figurative sense, he is focusing on the form of what is represented. Representation in both senses, for Piaget, is constitutive of sensory

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and motor experience. Consider, for example, Piaget’s classic analysis of the attempts of his 16-month-old daughter to retrieve a chain from an empty matchbox: “she looks at the slit with great attention, then several times in succession, she opens and shuts her mouth, at first slightly, then wider and wider . . . then puts her fingers in the slit . . . and grasps the chain” (Piaget, 1951, pp. 337-338). The mouth opening of the infant is considered by Piaget in both its transformational (operative) and figurative character to precursively represent the solution of opening the box to grasp the chain. Opening the mouth is an indication of the coordination of schemes for opening (operative representation) and at the same time an imitation of the figural dimensions of the opening of the box (figurative representation). Thus, representation in both senses is constitutive of the experience of that situation. For Kagan (1979) and Zelazo (1979), proponents of the informationprocessing approach to cognitive development, representation refers in a similar fashion to an assimilative interpretation of events by previously experienced event representations. The representational structure changes with development from a prototype, or “central tendency,” which summarizes information about instances of a concept, to a “standard,” a cognitive representation of an external event, action, or state, which is given a positive value, although is motivationally undesired (Kagan, 1981). Whether or not an event is visually attended depends upon the transformational distance of that event from representations of previously experienced events. Thus, in the information-processing model, as in the organismic (Piagetian) model, the previous experience of events is constitutive of the perception of current events. The Role of Experience from Direct Realism

Attending to events and acting in a certain fashion, in the view of direct realists, “depends upon past experiences but not on the storage of past experiences” (Gibson, 1966, p. 262). The anticipatory behaviors observed in infants both by Piaget and by Kagan and Zelazo (e.g., the opening of the mouth prior to opening the box, or the anticipation of the occurrence of an event) reflect, for direct realists, the preparatory activity of knowing. Preparatory activity “brings the knower to the threshold of perceptual experience, but does not participate in the perceptual experience” (Shaw & Bransford, 1977, pp. 35-36). Experience, in other words, is preparatory to but not constitutive of perceiving and acting. Can there be an anticipation of events without storage of past experiences? The experimental situations used by Kagan and Zelazo each have as prerequisites the presentation of a preliminary event, a prototype or standard, against which later events are presumed to be compared. One way to approach the question of whether prior stored experiences, or

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schemas, are necessarily constitutive of anticipations, therefore, is to examine whether anticipation of events can occur without presentation of some preliminary event. A study by von Hofsten (1980) on predictive reaching for objects by young infants suggests that infants directly perceive information which specifies the future position of an object with minimal experience of the trajectory of the object. Von Hofsten found that when infants as young as 18 weeks reach for a moving object while looking at it, they aim the ballistic movements of their hand to the point where it will meet the object rather than the point where the object is seen when the reach is initiated. Two methodological precautions reduce the likelihood that a schema directs the infant’s anticipatory reach. First, the results were based on von Hofsten’s analysis of the velocity and acceleration of the first three reaches in each of three different velocity conditions, thus minimizing the role of experience. Second, a trial consisted of the oscillation of an object in one direction, then another, so that no two consecutive object movements were in the same vector. There was, thus, no instance of repetition of the same event on successive trials, a requirement of the Kagan and Zelazo violation of expectancy paradigm. An additional result of the von Hofsten study argues against a schema-based explanation of anticipation. The subjects of the study were observed longitudinally until 36 weeks of age. There was no evidence of any increase in skill in predictive reaching between 18 and 36 weeks. This confirms the results of an earlier study by von Hofsten and Lindhagen (1979) who found no effect of practice on success at grasping an object. An important implication of the work of von Hofsten is that infants are able to perceive the potential future transformations of objects during the unfolding of an event. What the Kagan and Zelazo results may be demonstrating, therefore, is the increasing economy of the infant’s perceptual systems for noticing transformations. Consequences of Direct Realism for the Meaning of Representation The adoption of direct realism, the assertion that perception is direct, avoids the problems of referentiality and intentionality. The intentional object is the referential object. Perception is of “an object in the world and not some extraordinary object in the head” (Shaw et al., 1982, p. 175). The usage of the term “representation” which follows from this view is representation by, a userless concept, rather than representation for, a user-dependent concept. Thus, while it is not denied that there are neural representations of environmental situations, such representations correspond to the environment, but do not direct the perceiver (Reed, 1981). There is, thus, no user, or homonculus, in the head. What, then, directs the behavior of animal or human? In lieu of user-

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dependent information in neural representations, the direct realist places user-dependent information in the affordance structure of events that is dual to the user’s effectivity structure. By defining affordances as userspecific, i.e., scaled to a particular perceiver vis-a-vis the corresponding dual effectivities, the need for a homonculus in the head disappears. As is evident in the earlier example of the affordance of a cup for an infant, the user-specific meaning of the cup included information about occasion (psychological attitude) and agency (level of skill) of the infant in the context of a specific situation (time and place). Because affordances specify agent, occasion, and situation in relating the infant to the cup, no further information (e.g., memorial representation of past experiences of grasping the cup) is needed to explain how the infant gives meaning to the cup. An affordance because of its specificity to a dual effectivity, thus, is self-presenting (representing itself) rather than being representational (representing something outside itself) (Shaw et al., 1982). Given this ecological perspective on representation, the developmental task for the infant in the example of reaching for the cup is to notice that the cup affords grasping. The infant, in other words, must look for visual exteroceptive information about the cup relative to the layout of the environment, visual proprioceptive information about the position of his hand relative to his body, and visual exproprioceptive information about the cup relative to his hand. More on the development of noticing is presented in the next sections. Noticing It was observed earlier that the problem of referentiality in the models of representational realists led to the question of how the first schema which interprets perceptual input is selected. If perception of affordances is direct and the intentional object is the referential object, then the direct realist is confronted with a similar problem: how is a particular affordance selected given a specific goal? The answer proposed by Shaw et al. (1982) is to model affordances on a semantics of “possible worlds,” whereby an object or event may simultaneously specify several possible affordances. A particular combination of time andplace (situation) andpsychological attitude (occasion) by an agent with varying degrees of attunement (effectivity-based skill) directs the agent to notice particular affordances and not others. The possible world semantics of affordances and the thesis of direct realism have important implications for understanding the development of knowing during infancy. A general hypothesis offered here is that many of the skills attributed to the development of representation may alternatively be explained by the infant’s increasing skill at noticing particular

ECOLOGICAL

affordances in specific contexts given particular in order to accomplish some goal. Toward a Developmental

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psychological

attitudes

Model of Noticing

A start at building a developmental model of noticing from the perspective of direct realism has been made by Gibson (1982; Gibson & Rader, 1979). She reviews several studies which support a model of the education of attention to (or noticing of) affordances. The evidence suggests that the perceptual systems of humans are phylogenetically preattuned at birth to invariants which specify certain events, and that during ontogenesis, there is an increasing correspondence between the perception of these invariants and the utility of these invariants as affordances for skilled action. Consider two examples of optical invariants: texture gradients, which specify depth, and optical expansion, which specifies the imminent collision of an approaching object. Very young infants are able to visually pick up gradient information that specifies depth as is apparent by heartrate deceleration to the deep side of the visual cliff (Campos, Langer, & Krowitz, 1970). It is not until they are able to locomote at around 9 months, however, that they exhibit fear (as measured by heartrate acceleration) to the deep side of the visual cliff. During this period, moreover, infants use other perceived information (e.g., the mother’s facial expression) about the affordances of the perceived gradient to determine their behavior on the visual cliff. Sorce, Emde, Campos, and Klinnert (Note 3), for example, report that at the point where depth change occurs, infants will cross the deep side if the mother smiles, but not if she has a fearful expression. Similarly, infants as young as 1 month are able to visually pick up information about imminent collision (looming) and will respond with reflexive avoidance (Ball & Tronick, 1971). But it is not until around 8 months that they exhibit heartrate acceleration to imminent collision (Hruska & Yonas, Note 4). Thus, once infants become more skilled in coordinating motor acts, by acquiring appropriate effectivities, they become able to use information which they have been able to detect for many months because the corresponding complementary affordances have thereby also been determined. The relation between motor skill and the utility of invariants as affordantes is, however, only part of what determines whether a particular affordance is noticed. The roles of situation, or context, and occasion, or psychological attitude, also enter in. Context provides the boundary conditions which specify exactly how the degrees of freedom of movement must be constrained (Kelso & Tuller, 1981). One type of contextual constraint is the proprioceptive and expro-

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prioceptive postural context of an event. Certain postures of the body, e.g., sitting, preclude the occurrence of a number of other activities. When playing with a l-year-old infant, for example, mothers place the child in an upright position so that his torso and head are facing her. This effectively restricts the orientation of the infant’s movements so that they are directed toward her and directs the infant’s visual attention to certain events and not others. But postural adjustment and its visual concomitants only partially constrain the variation of the infant’s acts. The infant’s psychological attitude, the affordances of the objects that are used as props by the mother, and the affordances of the mother herself provide the remaining constraints which guide the infant’s acts. Consider, for example, the game of roll the ball played between mothers and infants (Hodapp et al., in press). Even when mothers appropriately adjust the infant’s posture so that the infant is facing her and the movement of his arms is limited to a restricted range, infants who are capable of returning the ball will often throw the ball away, rather than return it. Under these conditions, the mother is likely to begin to hold out her hand and, with this additional constraint, the infant is significantly more likely to return the ball. In the context of the playful psychological attitude induced by the game, and the partial constraint imposed by postural adjustment, the presentation of a hand which affords receiving the ball provides potentially useful information to “use up” the remaining degrees of freedom of the infant’s effectivities so that he is likely to return the ball. If this view is correct, the infant who returns the ball would be predicted to be more likely to look at (notice) the mother’s outstretched hand than infants who do not return the ball. The test of this prediction is presented later in this paper. In order to enter the variable of psychological attitude into the definition of affordances, it is useful to distinguish between two types of attitude: persistent and transient. The former has typically come under the rubric of cognitive style, or individual differences, while the latter concerns the affective quality of a particular act. An example of a transient psychological attitude is the positive affect that accompanies play. An important consequence of playful attitudes is that they facilitate the acquisition of skills and problem solving (Bruner, 1972). Mothers often take advantage of this positive affect and use the context of games to teach the child new meanings (affordances) of objects. The question of why a playful attitude facilitates learning remains to be studied. Persistent psychological attitudes or “styles” are also apparent in play, especially once it comes to be used to transform objects so that they afford novel forms and functions (what is called symbolic play). Wolf and

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387

Gardner (1979), in observations of symbolic play, distinguish between children who are either “patterners” or “dramatists.” The former are consistently more interested and skilled at configurational use of materials and making patterns and structures, while the latter express an overriding interest in what other people do and how other people can be affected. In transforming objects during play, for example, patterners often use visual similarities (e.g., using a soup spoon as an ice cream cone) while dramatists focus instead on function (e.g., anything that can be held and licked can be used for an ice cream cone). A reconsideration of the information specified by events in Table 1 suggests that persistent styles may direct children’s attention to different aspects of events. Events have two dimensions: structural invariants and transformational invariants. Perceiving the event of a rolling ball, e.g., specifies a unique transformation: rotation about an axis and translation at a uniform horizontal velocity. The ball itself is specified as a structural invariant which is rigid and round as it supports its own weight on a surface while rolling (though it may be elastic when squeezed). It is consistent with the Wolf and Gardner (1979) data to hypothesize that during play, patterners are more likely to notice the relation between the structural invariants of two objects (e.g., a ball and a picture of the full moon) and that dramatists are more likely to notice the similarity between two transformational invariants (e.g., rolling and bouncing). This is a researchable hypothesis. In summary, the ecological approach to knowing which follows from direct realism seems a viable alternative to the representational realism of the organismic and information processing models. Its foundation is the affordance-effectivity dual. The final section considers the utility of this approach for understanding behaviors observed during infancy which have been attributed to the onset of representation. THREE PRESUMED ROLES FOR REPRESENTATION IN INFANT KNOWING: EXAMINING PREDICTIONS FROM AN ECOLOGICALLY BASED ALTERNATIVE

As suggested in the previous sections, the ecologically based alternative to the representational realist’s account of knowing is the noticing of affordances. In the following sections three infant skills are considered: manual search for hidden objects, the use of objects as tools, and the use of an object as something to give as well as receive (complementary use of an object). Developmentalists who ascribe to representational realism (as discussed earlier) assert that each of these skills reflects the infant’s capacity to evoke representations in order to give meaning to his perceiving and acting. Studies of each of these skills conducted by the author

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and by others are presented in order to examine alternative predictions made by representational and direct realists, respectively. The three sets of predictions are first summarized below for each skill, and then considered in greater detail. I. Errors in Search for Hidden Objects (a) Representational realism. Errors in search for hidden objects are tied to motor representations (motor sets) which disambiguate visual sensory data about the location of an object (Piaget, 1954). (6) Direct realism. Errors in search for hidden objects reflect the noticing of the location where an object was last seen occluded (Butterworth, Jarrett, & Hicks, 1982; Goldfield & Dickerson, 1981). 2. Tool Use (a) Representational realism. Using a rake as a tool to retrieve an object hidden inside a cylinder is tied to the ability to evoke a representation of the means-ends relation between the rake, cylinder, and hidden object (Casati & Lezine, 1968). (b) Direct realism. Using a rake as a tool to retrieve an object hidden inside a cylinder is tied to the ability to notice that acts which are complementary (i.e., exert reactive forces in opposite directions) may be directed toward the same goal (Goldfield, 1983). 3. Complementary

Use of Objects

(a) Representational realism. Treating an object as something to be given as well as received is tied to object permanence, giving the perceived object spatiotemporal reality independent of actions on the object (Lezine, 1973). (b) Direct realism. Treating an object as something to be given as well as received is tied to the noticing of affordances which support the effectivities involved in receiving and giving (Goldlield, Note 5; Hodapp et al., in press). Representation

and the Search for Hidden Objects

In Piagetian theory (e.g., Piaget, 1952), the infant’s manual search for hidden objects toward the end of the first year reflects an important change in her understanding that objects persist independently of actions on them (object permanence). Piaget uses errors in search as the major index of this change. During sensorimotor stage 4, for example, infants will search for a hidden object, but will also make a peculiar error. If allowed to find the object (a toy) at one location, A, and the toy is then hidden at another location, B, the infant will search where the object was

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389

previously found, at A, rather than where it was last seen, at B. This well-documented phenomenon (Gratch, 1975) is referred to as the AB error. The ecological approach to perceiving presented here takes exception with Piaget’s analysis of what happens to the object, from the infant’s perspective, when it is hidden. Piaget (1952) claims that when an infant sees an object occluded, she experiences it disappearing in the sense of going out of existence. The shift from incorrect search (the AB error) to correct search, therefore, reflects the child’s ability to represent the object’s existence when it disappears. Gibson (1979) emphasizes, however, that going out of sight and going out of existence are distinct events. The information which specifies the former is occlusion, while the information specifying the latter is dissolution (Gibson, Kaplan, Reynolds, & Wheeler, 1969). Given that occlusion directly specifies going out of sight and not going out of existence, there is no reason to believe that the infant perceives dissolution when an object is hidden. An alternative view of what is reflected by errors in manual search is that the infant is learning to notice the location at which the object was last seen occluded in order to find the object. A prediction that follows from this view is that the infant’s visual tracking, i.e., noticing of the location of the object’s occlusion, is related to errors in manual search. It is argued, in other words, that the infant is making errors because of a failure to notice information about occlusion, not because of an inadequate representation of the object. Goldfield and Dickerson (1981) examined this prediction by exploring the relation between infant visual tracking and correct search on a hidden object task. Four groups of infants (a total of 48) were presented with the task of finding a toy hidden in one of two covered containers. There were two age groups, younger (8.5month-olds) and older (9.5month-olds) and two types of covers over the containers, same color (nondistinctive) and different colors (distinctive). On each of six trials, infants were first allowed to find the toy at a single location. The toy was then hidden in the same or different container. Infants were then spatially reoriented relative to the containers, either by being moved around the platform supporting the containers (move-infant trials), by rotating the platform by 180 degrees (move-platform trials), or by moving and then returning the infant to her original position (control trials). Of interest here is the infant’s visual tracking of the correct location during reorientation on the trials in which the toy was hidden in the same container, with the control trials eliminated. Table 2 presents the contingency between visual tracking and correct search as a function of age and distinctiveness of covers. In all but one instance, the proportion of

390

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2

PROPORTION OF CORRECTRESPONSES ON SAME-CONTAINER TRIALSAS A FUNCTION OF VISUAL TRACKINGOF CORRECTLOCATION DURING REORIENTATION Reorientation trials Group Younger Nondistinctive Younger Distinctive Older Nondistinctive Older Distinctive Combined

Tracking

Move platform

Move infant

Yes No Yes No Yes No Yes No Yes No

.40 .I4 .44 .33 .67 .50 .86 .80 .59 .43

.25 .25 .27 .oo .50

.lO .60 .oo .41 .I4

Note. From (Goldfield & Dickerson, 1981).

correct responses is higher on trials on which visual tracking occurred. Two chi-square tests, one for move-platform and one for move-infant trials, were conducted in order to determine whether the relation was statistically significant. The tests compared correct and incorrect responding on trials where visual tracking did and did not occur for all 48 infants. The results indicated that the contingency was statistically significant for move-infant trials, x2 (1) = 4.01, p = .045, but not for move platform trials, x2 (1) = 1.28, p = .2.58.Thus, the infant’s visual tracking of the location of the object’s occlusion is related to errors in manual search, especially when there is a change in visual exproprioceptive information (movement of the infant relative to the environment) and persistence in exteroceptive information (location of the object relative to the distinctive covers). Other Studies The process of developing a concept of permanent object, in Piaget’s view, is tied to motor representations which disambiguate visual sensory data about the location of an object. The AB error, in this view, is seen as a consequence of only a partial interpretation by the as yet fully formed representation. There are now several studies in addition to Goldfield and Dickerson (1981) which provide evidence against this interpretation of the AB error. The child need not actually form a motor set by searching manually for the object at a single location for the error to occur. Observation alone of the object repeatedly hidden at location A results in perseveration after the object is moved (Bremner, 1978).

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391

In support of the Goldfield and Dickerson (1981) finding of a relation between error and patterns of visual attention, Butterworth et al. (1982) argue that errors in search for hidden objects are the result of the infant’s failure to use a visually specified context to locate objects. In a condition where background was continuous and covers were distinctively different, infants between the ages of 8 and 10 months were less likely to make errors than in other conditions because successive loci on the same surface (visual exteroceptive information) were discriminable regardless of the infant’s position. It thus appears to be the infant’s attention to the spatial relation between covers and background that determined patterns of manual search. Representation

and Tool Use

The inventive or insightful use of objects as tools develops in humans during the second year (though as Charlesworth, 1979, suggests tool use may not occur often in natural contexts). Invention is a rapid process of coordinating means-ends activity, unlike the slow deliberations of trial and error. Piaget (1952) asserts that such inventions become possible as the child is increasingly able to represent means-ends situations without depending upon the “actual data of perception.” A task used by Piagetians to examine the development of inventive tool use is a cylinder-rake task which requires the child to retrieve an object which is seen placed inside an opaque cylinder (Casati & Lezine, 1968). Because the child cannot see the object once it is placed inside the opaque cylinder, it is reasoned that the child must evoke a representation of a means for dealing with the object inside the cylinder. Kopp, O’Connor, and Finger (1975) have found, however, that when the cylinder used is transparent, younger infants remain unable to get the object. This suggests that representation is not what makes invention possible, since even without the necessity for representation younger infants are unable to find a solution to the problem. Another possibility is suggested by considering the task in terms of Fowler and Turvey’s (1978) usage of affordances: the reactive forces resulting from the infant’s movement of rake and cylinder. To solve the problem, from this perspective, the child must notice that when held in each hand, the rake and cylinder, respectively, afford reactive forces which occur in opposite directions. The hands, in other words, must be used in a complementary fashion. Controlling reactive forces which occur in opposite directions may be a general skill that develops as a consequence of the symmetry of the human body. The biological structures of the human body have forms which seem to have evolved to take advantage of forces working in opposite directions, e.g., the opposed thumb and forefinger of the human

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hand, and the bilateral symmetry of the limbs. Man-made objects, e.g., a nut and bolt, a lever, and other tools, may be considered as a cultural “noticing” of the usefulness of harnessing forces which occur in opposite directions. Human ontogeny during infancy, therefore, may have as one of its tasks the education of attention to complementary activity. A longitudinal study by the author examined infant performance on the cylinder-rake problem with the complementarity hypothesis in mind. Eleven infants were each administered the cylinder-rake task and a picture-showing task at 16, 18, and 20 months. Each task required that, to achieve a goal, two activities that were complementary to each other had to be directed toward the same goal. On the cylinder-rake task, the child had to orient the handle of a rake to poke a cookie from inside a cylinder. Similarly, on the picture-showing task, the child had to orient the picture in the direction of the visual gaze of the observer so the observer could see it. The method of hypothesis testing in this study was to (i) predict a sequence of developmental steps toward the control of complementary acts, (ii) determine if children progressed through the predicted sequence on the two tasks, and (iii) determine if a stronger relationship between the tasks emerged during a limited interval, namely, 19 and 21 months. At this age a major advance in cognitive competence, attributed to the onset of a capacity for memorial-conceptual representation (McCall, Eithorn, & Hogarty, 1977) has been demonstrated. To minimize the likelihood that a memorial representation of the relation between object and goal was responsible for developmental changes on the cylinder-rake task, a transparent cylinder was used to enclose the cookie. The hypothesis of sequentiality predicts that infants progress through the same sequence of predicted levels on both tasks. There were three predicted levels. At level 1, infants manipulate a single object so that its reactive forces (affordances) are in the same direction of movement as the upper limbs (e.g., striking the table with a rake or giving the picture to the experimenter). At level 2, infants perform simultaneously two independent activities with objects or persons (e.g., moving the rake with one hand while holding the cylinder with the other, or showing the unoriented picture to the experimenter while looking at his face). The infant does not, however, treat the two activities as complementary to each other. At level 3, infants treat two independent activities with objects or persons as complementary to each other (e.g., orient the rake and cylinder so that moving them in opposite directions affords retrieving the cookie, or orienting the picture while looking at the experimenter to afford showing to another person). The fit to the predicted sequence of tool use and picture showing through three progressive levels was examined by testing whether per-

ECOLOGICAL

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APPROACH

formance on each of the tasks fit a rank ordering of level 1 at 16 months, level 2 at 18 months, and level 3 at 20 months. Of interest was both the distribution of subjects at each level at each of the three tests and whether or not there were any reversals in progression through the levels. If there were few reversals, then a stronger case could be made for the particular predicted sequence. On both tasks the greatest number of subjects appears at level 1 at 16 months, level 2 at 18 months, and level 3 at 20 months. Eighty-two percent (9 of 11) of the subjects showed later steps in later sessions on the cylinder-rake task, with the two remaining subjects showing a reversal of one step. On picture showing, 70% (8 of 11) of subjects showed later steps in later sessions with the three remaining subjects showing a reversal of one step. A Friedman analysis of variance was computed separately for each task. The predicted sequence was confirmed for both problem solving, x2(2) = 9.86, p < .Ol, and picture showing, x2(2) = 5.60, p < .06. The hypothesis of interval synchrony between the tasks at 20 months and not sooner predicts that there should be a stronger relationship between the tasks when the infant is able to coordinate complementary activities, i.e., orient the picture to the observer and the cylinder to the rake. This was tested by computing the contingency of orienting on both tasks (see Table 3). Scores were dichotomized, with 0 assigned to infants who did not orient on either task, and 1 assigned to infants who oriented on both. A Cochran Q test indicated a significant difference between the probabilities of orienting both the rake-cylinder and picture at 20 mo as compared with 16 or 18 mo, x2(2) = 10.00, p < .Ol. TABLE 3 CONTINGENCY

Picture showing (orient picture to observer)

BETWEEN TYPES OF ORIENTING

ON Two

TASKS

Means-Ends (orient instrument to cylinder) No

Yes

II 0

0 0

Yes

9 0

2 0

No Yes

4 0

2 5

Age (in months) 16 No Yes 18 No 20

Note. Reprinted, with permission, from “The development of control over complementary systems during the second year,” by Eugene C. Goldfield, Infant behavior and developmenf, p. 261. Copyright 1983 by Ablex Publishing.

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Both the sequence and synchrony analyses, thus, support the view that the ability to combine complementary activities underlies performance on both tasks. Since the infants were not required to evoke a memorial representation of any of the task components, the assertion that invention reflects the development of representation must be questioned. Other research. Two studies on the use of levers by infants offer support for the view that the ability to coordinate complementary activities develops during the second year. Levers are tools whose use results in directing physical forces in opposite directions. For a lever whose fulcrum is at its center, movement of one end of the lever in one direction results in an equal but opposite motion of the other end of the lever. Richardson (1934) presented a group of 7- to 12-month-olds with a horizontal lever pivoted at the near end. A grill was placed between the child and the lever to prevent him from directly reaching a toy attached to the lever. The toy could be brought within reach either by (a) pushing the short arm of the lever or by (b) pulling the long arm of the lever. Richardson (1934) observed that even for the 12-month-olds, the predominant means of rotating the lever was to reach for the longer arm and pull it, rather than pushing the shorter arm. The 12-month-old was, thus, capable of using the lever as a tool to get the toy only by pulling the longer arm in the same direction as movement of the toy. The same child, however, failed to apply force to the shorter arm in a direction opposite to that in which the toy moves. Koslowski and Bruner (1972) examined the development of the child’s ability to use a lever as a tool when the lever rotated freely in the horizontal plane. Subjects were children between the ages of 1 and 2 years. Each was seated at one end of the lever and a toy was placed at the opposite end. The goal for the child was to get the toy. Twelve- to fifteenmonth-olds tried to reach out and grab the toy directly, ignoring the lever. This is analogous to the behavior of the 12-month-olds in the Richardson (1934) study. Between 15 and 18 months, the predominant activity was to rotate the lever back and forth, without trying to get the toy. By around 20 months, subjects were likely to rotate the lever to bring the toy within reach and grab it. It is, thus, not until around 20 months, the same age as in the Kopp et al. (1975) and Goldfield (1983) studies, that the child was able to use a lever which produces movement in equal but opposite (complementary) directions relative to the movement of the child’s hand. Representation and the Complementarity of Agent and Recipient Progressively during infancy, children become able to perceptually differentiate the complementary functions of the agent and recipient of an action (Golinkoff, 1981). In Piagetian theory, there is assumed to be a strong link between the capacity for such differentiation and the emer-

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395

gence of representation as measured by object permanence. Lezine (1973), for example, observes that “only when the object becomes permanent and endowed with spatiotemporal reality can the child decentrate himself, differentiate goals from means and establish alternate paths to the object” (p. 223). Under the assumption of direct realism, the noticing of appropriate contextual support for perceiving the affordances of objects, not representation in the Piagetian sense, is what makes differentiation of complementary functions possible. This is apparent in the game of roll the ball played between mothers and their 8- to 16-month-old infants (Hodapp et al., in press). When an infant begins to return the ball for the first time, after receiving it from the mother, this indicates that the ball has two complementary meanings for the infant: it is something which affords taking and giving. If the direct realism assumption is correct, then it is the infant’s noticing of the context provided by the mother that is critically involved in his developing ability to give the ball as well as take it. Research on the game of roll the ball (Goldfield, Note 5; Hodapp et al., in press) examined (a) whether the mother’s act of holding out her hand to receive the ball had any effect on the infant’s behavior, (b) whether the infant’s looking at (noticing) the mother’s outstretched hand was related to his age of onset of first return of the ball, and (c) whether the infant’s first return of the ball was related to the development of object permanence (a major Piagetian criterion of representation). Seventeen mother-infant dyads were observed longitudinally as they played the games of roll the ball and peek-a-boo, initially when the infants were &months-old, and then monthly until 16 months (for a total of nine observations of each infant). Each of the sessions was videotaped. The results of the Hodapp et al. report are based on analysis of both games on each month relative to the month of onset of a criterion skill (e.g., whether they return the ball). The results of Goldfield (Note 5) are based on an independent analysis of roll the ball. This analysis looked only at the month prior to and the month on which the ball was first returned. In both analyses, though, infants were equated on the first month of a criterion skill regardless of their actual chronological age. Hodapp et al. (in press) addressed issues (a) and (c). The percentage of ball returns a child performs during rounds on which the mother holds out her hands was compared to the percentage of returns on rounds on which the mother does not hold out her hands. Children return the ball more often when mother’s hands are outstretched than when they are not on most months after the first return begins. While this result does not reach statistical significance on the first month the child can return the ball, it does on the second, t(16) = 4.28, p < .OOl, and third months, t(16) = 2.53, p < .05.

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It appears not to be the mother’s hands alone which have an effect on whether the infant returns the ball, but also the context in which return is requested. If one compares the age at which infants first return objects when the hand is held out during a game with a non-game testing situation (administration of the Uzgiris-Hunt tests), there is a clear difference in the child’s behavior. Infants return objects an average of 1.67 months earlier in the roll the ball game than during test situations, t(16) = 3.20, p < .Ol. Thus, the psychological attitude of playfulness of the infant during participation in the game appears to facilitate the use of information which supports the act of returning the ball. Administration of the Uzgiris-Hunt scales also addresses the relation of first ball return and the onset of mental representation (as measured by object permanence). Infants were administered the Piagetian stage IV object permanence tasks of the Uzgiris-Hunt scales following game playing during each session. There was a correlation of .36 between returning the ball and object permanence. Thus, treating the object as something to be given as well as received is not tied to object permanence, as Piagetians suggest. Goldfield (Note 5) examined whether age of onset of first ball return was related to the development of noticing, i.e., whether the infant was more likely on the onset month than the previous month to look at the mother’s outstretched hand. Because behavior on the month prior to the first ball return was of interest, three infants who returned the ball on the first month they were observed (and hence had no prior month) were excluded from this analysis. An additional infant was excluded because her face was often turned away from the camera and her visual activity was not storable. Infant noticing was examined by scoring the particular target of visual fixation during each turn, or round, of the game. It was determined that of all possible targets, four accounted for nearly all of the infant’s looking during the game (suggesting that the game context places constraints on looking, as hypothesized). These four targets were mother’s face, mother’s hands, the ball, and away. Table 4 presents a summary of the measures used to examine the infant’s looking at particular targets and the relation of looking at the mother’s hand to opportunities for looking. An analysis of the four scored targets indicates that there was a decrease in the mean number of targets looked at from the prereturn to onset month, but the difference between the means was nonsignificant. A comparison of the frequency of maternal hands out indicated significantly more holding out the hands on the onset month as compared with the preonset month of infant ball return, t(12) = 2.40, p < .05. This value differs somewhat from the Hodapp et al. (in press) data because they

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TABLE 4 SUMMARYOFMEASURESOFINFANTLOOKINGIN THE ROLLTHEBALLGAME Month prior to first ball return Mean number of infant looks at all targets Mean number of maternal hands out Mean number of infant looks at mother’s hand Mean proportion of infant looks at hand relative to all targets Mean proportion of infant looks at hand per opportunity

Month of first ball return

24.54

19.46

4.23*

8.00

.77**

3.62

.03***

.I9

.18**

.45

* p < .05. ** p i .Ol. *** p cc ,001.

looked at the number of rounds on which at least one maternal behavior occurred, while the present analysis looked at the actual number of hands out on all rounds. There were significantly more looks at the mother’s hand from preonset to onset month, t(12) = 3.25, p < .Ol, and more looks at the hand than at other targets, t(12) = 4.43, p < .OOl. When the opportunity for looking was taken into consideration by computing the proportion of looks per maternal hands out, infants remained significantly more likely to look at the mother’s hand on the first month of ball return than the previous month, t(12) = 4.25, p < .Ol. When considered together, all the measures confirm the prediction that first return of the ball is related to the infant’s noticing of the mother’s hand. Thus, the infant’s psychological attitude (playfulness), level of skill, and the presence of the mother’s hand jointly provide the constraints that define the ball as something which affords returning. Other research. Playful use of objects occurs not only during social games, but also in more solitary pretend play. Studies of pretending that have looked at the infant’s ability to differentiate the complementary functions of objects (e.g., agent and recipient of actions) indicate that infants do not fully attribute agency to objects and persons until some time during the second year (Wolf, 1982). When presented with a pillow during play, for example, l-year-old infants typically either put their own head on the pillow to pretend to sleep, or put a doll on the pillow (Watson & Fischer, 1977). In pretend play, as in social games, therefore, noticing the potential function of objects (i.e., their affordances) devJops only gradually. But does this development depend upon representation?

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Data from Watson and Fischer (1977) indicate that treating objects as agents is, at best, weakly related to object permanence. A strong version of the representation hypothesis would hold that steps in the achievement of object permanence correlate highly with steps in the development of agency in play. Watson and Fischer (1977) report, however, a correlation of .62 between agency in play and object permanence. Age also correlated with agency in play, at about the same level, S9. In conjunction with the Hodapp et al. (in press) finding of a low correlation between treating a ball as an agent (something which affords returning) and object permanence, the representation hypothesis is not well supported. CONCLUSION: STUDYING INFANT KNOWING AT THE CORRECT GRAIN OF ANALYSIS In all three of the skills reviewed, the noticing of useful affordances is a critical determinant of whether the infant is successful in achieving a specific goal. In addition to psychological attitude and level of skill, task demands partially constrain which affordances are noticed or ignored. Given the task of finding an occluded object during change in position of the body relative to the occluded object, infants who notice useful spatial relations (i.e., those that remain invariant with changing body position), and ignore those that do not remain invariant, are likely to succeed in finding the occluded object. Successful infants notice invariant exteroceptive information (the persistence of the object over transformation) and ignore visual exproprioceptive information (transformations revealed by changes in body position). The latter is not a useful frame of reference for locating objects when the body moves through the environment. On the means-ends problem of retrieving an embedded object (a cookie) with an instrument, the task requirement of using both hands partially constrains the effectivities that are useful for getting the cookie. The infant who notices that the movement of the rake and cylinder held in each hand is complementary (i.e., occurs in opposite directions) is likely to be successful in achieving the goal of removing the cookie. And in the game of roll the ball, the infant who notices the mother’s hand in the context of the playful attitude engendered by the game is likely to be successful at returning the ball to the mother. When she offers a hand to receive the ball, the mother completes a contextual “scaffold” which supports the effectivities involved in returning the ball. An implication of the results of the studies reviewed for each of these skills is that the infant’s ability to notice the usefulness of certain affordantes and not others is what best characterizes sensorimotor knowing. The alternative view of representational realists that sensorimotor development involves the construction or abstraction of a sensorimotor

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system, it is argued here, is the result of a failure to consider sensorimotor behavior in its natural context. From his extraordinary observation of infants, Piaget (1951, 1952, 1954) developed a model of how the infant constructs (i.e., represents) reality. In his attempt to maintain scientific objectivity in the study of infant behavior, Piaget failed to consider his impact as a socializing agent on the infant’s self-regulatory activity (Goldfield & Hodapp, Note 2). His interpretation of the infant’s behavior was, thus, removed from the context which contributes to its meaning. As a consequence, Piaget was forced into the belief that the infant did not perceive the meaning of objects apart from his own action schemes. The infant constructs a representational system to give meaning to objects independent of his own action schemes. By returning the study of the infant to the social milieu and examining how infants discover the affordances of objects relative to their own effectivities and those of the caregiver, it becomes apparent that both play a role in sensorimotor organization. During the perinatal period, the infant’s participation in sensorimotor organization is largely a function of psychological attitude determined by endogenous affective states (Emde, Gaensbauer, & Harmon, 1976; Wolff, 1966). What seems to change during early development is the infant’s ability to marshal1 these arousal states to direct the perceptual systems to those affordances which support effectivities maintaining arousal at an optimal level. The caregiver, during this period, uses behavioral indices of infant arousal (e.g., facial expression, gaze, and vocalization) to assist the infant in noticing certain information. On the occasion of hunger signaled by the infant, for example, the breastfeeding mother assists the infant in noticing the breast by placing him in an appropriate posture, Gradually, on subsequent occasions of hunger, the arousal state itself directs the infant’s attention to the breast as affording sucking. During subsequent months of the first year, the mother uses behavioral indices of interest during play as signals for her to modify the environment so that the infant notices information that is useful for meeting other needs. When the infant loses interest in a game, the mother changes the game so that it becomes a novel variation on a theme (Hodapp et al., in press; Stern, 1977). Thus, even in the earliest months of infancy, both infant and caregiver participate in the regulatory process involved in sensorimotor organization. A final point to be made about the value of placing the study of the infant’s sensorimotor development within a social context is that it provides a means of establishing continuity with later competence, e.g., language and complex social relations. Indeed, the history of the study of children’s language (see Bates, 1982, for a review) illustrates how

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studying sensorimotor acts in a social context provides a very different picture of the child as a learner. The earliest grammars, e.g., Braine’s (1963) pivot grammar, were based on analysis of word sequence or order. But it soon became apparent that the order grain of analysis of utterances could not account for the different meaning of utterances in different contexts (Bloom, 1970). The advent of case grammars (Brown, 1973) brought context into the analysis of children’s utterances by examining semantic relations such as location, agency, etc. But case grammars, while context sensitive, were entirely structural analyses which did not take into account the function or value of words for the speaker/listener, i.e., the pragmatics of words. The current focus on the pragmatics of linguistic utterances (e.g. Dore, 1979) brings the study of words from the order and relation grains to the analysis of value, the noticing of utterances for their communicative usefulness in particular situations. The pragmatic analysis of words gives language a foundation in the earliest acts of the infant nested in the social milieu. Bruner (1978) has demonstrated, for example, that young infants can sustain joint attention, convey intentions, and take turns, all part of later conversational competence. Because competence at selecting speech acts for their communicative value is inherent in the earliest social interactions, continuity is provided between these early speech acts and later messages encoded in linguistic utterances. The lesson to be taken from the history of the study of child language, and hopefully, from this article, is that a context-sensitive analysis of infant sensorimotor knowing is needed. Such an analysis should be directed toward understanding the evolution of the process of selecting information for its pragmatic value: the noticing of affordances. REFERENCES Ball, W., & Tronick, E. Infant responses to impending collison: Optical and real. Science, 1971, 171, 818-820. Bates, E., Bretherton, I., Beeghly-Smith, M., & McNew, S. Social bases of language development: A reassessment. In H. W. Reese & L. P Lipsitt (Eds.), Advances in child development and behavior (Vol. 16). New York: Academic Press, 1982. Bloom, L. Language development: Form andfunction in emerging grammars. Cambridge, Mass.: MIT Press, 1970. Braine, M. D. The ontogeny of English phrase structure: The first phrase. Language, 1963, 39, 1-13. Brazelton, T. B., nonick, E., Adamson, L., Als, H., & Wise, S. Early mother-infant reciprocity. In M. Hofer (Ed.), The parent-infant re/ationship. Summit, N.J.: CIBA, 1975. Bremner, J. G. Spatial errors made by infants: Inadequate spatial cues or evidence of egocentrism? British Journal of Psychology, 1978, 69, 77-84. Brown, R. A first language: The early stages. Cambridge, Mass.: Harvard Univ. Press, 1973.

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REFERENCE

NOTES

1. Warren, W. A biodynamic basis for perception and action in climbing. Unpublished doctoral dissertation, University of Connecticut, Storm, 1982. 2. Goldfield, E. C., & Hodapp, R. M. The role of the caregiver in regulating cognitive development: An illustration from early games. Paper presented at the 12th annual meeting of the Jean Piaget Society, Philadelphia, 1982. 3. Sorce, J., Emde, R., Campos, J., & Klinnert, M. Maternal emotional signaling: Its effect on the visual cliff behavior of one-year olds. Paper presented at the biennial meeting of the Society for Research in Child Development, Boston, 1981. 4. Hruska, K., & Yonas, A. Developmental changes in cardiac responses to the optical stimulus of impending collision. Paper presented at the meeting of the Society for Psychophysiological Research, St. Louis, 1971. 5. Goldtield, E. C. When does a ball afford returning? An ecological analysis of a motherinfant game. Paper presented at the biennial meeting of the Society for Research in Child Development, Detroit, 1983. RECEIVED:

September 21, 1982; REVISED: February 15. 1983.