Implications of Object Permanence
Definitions of Object Permanence
Knowledge that an object continues to exist when there is no longer sensory input from the object.
A sensorimotor organization of schemes, completed by about 18 months of age, that enables the infant’s organization of reality into a world of objects, including the infant as one of them. – Piaget.
Inference, that an infant knows innately or early that objects exist when occluded, based on longer infant looking when an inferred expectation, resting on the assumption of that knowledge, is violated, and on additional assumptions that violation of expectation results in surprise and surprise results in longer looking.
Practical Implications of Object Permanence
Knowing that something exists when not perceived implies that the knowledge exists free of sensory input and suggests it can be used mentally without sensory support. The knowledge has been freed from the limitations and constraints of time, space, and perception. The knower no longer needs perceptual contact with the known for knowledge to exist. Such liberated knowledge underlies mental manipulation of the world, imagination, expectation, memory, and prediction.
Before object permanence, when knowledge depends on, and is essentially equivalent to, perception, disappearance of the object is disappearance of the knowledge. Out of sight is literally out of mind. The difference resembles the difference between following an argument and understanding it. Following requires presentation in some way, such as spoken or written, and depends on engagement with each step of the presentation. Understanding means one can know it without it being presented. It is independent of perceptual processes. Following requires a certain level of comprehension but does not ensure that knowledge endures after presentation ends. Understanding liberates knowledge from perceptual engagement. Object permanence is the analog of understanding with respect to knowledge of the existence of objects and events.
With object permanence, objects can exist in memory, serve prediction, and also imagination. Object memory, predicting how an object will behave, or imagining what an object might be doing, all require objects that are mentally freed from perception. Object permanence enables mind to transcend the actuality of here and now. The child with object permanence can watch someone drive off in a car but know that the person continues to exist, or watch an airplane fly into a cloud and expect it to emerge. In the predator–prey relation, prey goes behind a tree or a rock but still exists for predator. From prey’s perspective, predator is no longer in sight but is still a problem. Where object permanence is limited, fear maintained by body chemistry can support continued flight even when the out of sight predator may not be mentally represented. Object permanence helps both predator and prey to survive.
Theoretical Implications of Object Permanence
Piaget (1954) introduced object permanence. He discovered that when an object is concealed, 5- and 6-month-old infants seem to no longer be aware that it exists.
In Piaget’s theory, schemes are cognitive structures for assimilating reality and enabling generalization of action to similar situations. Knowledge of the continued existence of objects that are no longer visible results from a progression of schemes, i.e., coordinations and organizations of looking and reaching.
Piaget found that the 9-month-old could remove an occluder to reveal a recently hidden object but still lacked some of the visual-motor coordination that would define complete object permanence. Along the 18-month or so path to completing the sensorimotor stage of development where the child structures the world and itself into a collection of permanent objects, the child succumbs to and then solves a series of puzzles, including the well-known A-not-B problem. If an object is hidden at location A, and then, as the infant watches, is moved to and concealed at location B, when the infant is allowed to reach for the object, reaching occurs to location A. By 12 months, the infant reaches directly to location B.
By 18 months, the system of coordinations of visual-motor schemes is sufficiently complete for the infant to organize its world into objects that exist independently of action and perception, including the infant itself as one of those objects. As the child constructs reality by comparable coordinations involving space, time, and causality, it is gradually freed to grasp an external world of which it is a part.
From Piaget’s perspective, object permanence implies the completion of the sensorimotor stage of cognitive organization.
Nativist and Other Challenges to Piaget
Might the 5-month-old or younger, in a competence–performance contradiction, know that occluded objects continue to exist but be unable to display that knowledge because it does not yet have the required eye–hand coordination? The child knows but cannot display the knowledge. If so, introduction of a task that does not require removing an occluder might reveal object knowledge at an earlier age than claimed by Piaget.
Bower (1966, 1967) studied this possibility, and Bower et al. (1971) used a visual tracking task in which 20-week-old infants watched an object pass behind an occluding screen and then shifted their gaze to where the object would be expected to appear. If a different object appeared, this disturbed tracking. These findings suggest representation of an occluded object exists earlier than Piaget supposed. But Bower and Patterson (1973) showed that visual tracking movements continued even when the moving object was halted in plain sight, indicating a possible inertial component to tracking rather than occluded object representation.
Baillargeon et al. (1985) habituated 5-month-old infants to rotation of a drawbridge-like screen and then placed a block behind the screen. The infants were shown trials where screen rotation stopped at the point where the block would have kept the screen from further rotating, and trials where the screen seemingly rotated right through the block. In both trial types, the screen reversed its trajectory revealing the block remaining where it had been placed. Longer looking to the “impossible” event was attributed to surprise resulting from violation of expectation of the block still being there and preventing complete screen rotation. The authors take this to reveal a form of object permanence occurring much earlier than Piaget predicted. Other studies are taken to support this finding (e.g., Baillargeon and Graber 1987).
Spelke and her associates (e.g., Spelke et al. 1992) have argued for innate core knowledge such as movement continuity and object solidity that enable the above apparent object permanence in the very young infant.
Baillargeon frequently invokes high level cognitive processes such as representation, assumption, expectation, surprise, belief, reasoning, inference to explain results in violation of expectation experiments with young infants.
Piagetian theory says that object permanence develops slowly as a result of interaction with the world and the organization and coordination of schemes. The implication of the nativist position with respect to the early occurrence of object permanence is that the Piagetian formulation of the development of object permanence may be wrong and raises doubts about the entire theory.
Challenges to the Nativist Position
The Perceptual Processing Response
Brilliantly challenging the nativist position, Haith (1998) argued that “Since virtually all of the nativist claims for early cognitive processes hinge on how long an infant looks at one display rather than another ... investigators who pursue high-level cognitive constructs must play the default game. That is, one must fend off every possible perceptual interpretation of differences to entertain default cognitive interpretations,” and this will involve many factors that affect looking, including variations in the perceptual dimensions of objects and people, familiarity, novelty, recency, predictability, and the time lapse between stimulus exposures. Haith cites numerous studies that call into question nativist high level cognitive interpretations (e.g., Bogartz et al. 1997; Cohen, 1995: Cohen et al. 1996).
Bremner et al. (2015) provide another excellent alternative to the nativist position. “Rather than advance object persistence as an innate principle through which events are interpreted, ... persistence is specified by perceptual events such as deletion and accretion, and the developmental question is about infants’ changing ability to perceive object persistence on the basis of these cues.”
Parsimony claims abound. One response from Baillargeon (2000) has been to argue that greater parsimony results from attributing higher level processes to the infant, as opposed to detailed analyses calling for multiple explanations when perceptual processing analyses of the behavior are proposed. One counter to this claim is that it is not parsimonious to attribute higher level processes where lower ones will do.
The Dynamic Systems Approach
Another parsimony counter to the nativist claim is implicit in the Dynamic Systems approach of Schöner and Thelen (2006). They “offer a dynamic field model of infant visual habituation, which simulates the known features of habituation, including familiarity and novelty effects, stimulus intensity effects, and age and individual differences” and “provide simulated visual input of varying strengths, distances, and durations to 2 coupled and interacting fields. The 1st represents the activation that drives ‘looking,’ and the 2nd, the inhibition that leads to ‘looking away,’ or habituation.” By varying the parameters of the field, the authors simulate the time course of habituation trials and show how these dynamics can lead to different depths of habituation, which then determine how the system dishabituates. The authors use the model to simulate a set of influential experiments by Baillargeon (1986, 1987a, b) using the well-known “drawbridge” paradigm. The dynamic field model provides a coherent explanation without invoking infant object knowledge. “And importantly for the parsimony argument, the authors show that small changes in model parameters can lead to qualitatively different outcomes. Because in typical infant cognition experiments, critical parameters are unknown, effects attributed to conceptual knowledge may be explained by the dynamics of habituation.” Thus, dynamic systems theory provides a rationale for why multiple explanations are necessary in perceptual processing analyses of the behavior that nativist claim indicate object permanence.
Schöner and Thelen (2006) indicate that all that the Violation of Expectation studies definitely show is that the infants notice a difference between the two events they have been shown. Everything else is an extrapolation from this. Schöner and Thelen argue that there are many reasons why infants might prefer looking at the “impossible” events. For example, in the “drawbridge” study, the “impossible” event involves more movement than the “possible” event. They conclude that Baillargeon has mistakenly assumed that the only difference between her stimuli is that one is “possible” and the other is “impossible.” However, there are actually many differences between the two stimuli, any of which might be the reason why infants look more at one than the other. What Baillargeon and Spelke claim is evidence of innate or early knowledge of the physical world, Schöner and Thelen say is no more than the effect of confounding variables.
The practical implications of object permanence are that knowledge and understanding of a world filled with objects and events require the ability to represent such a world in the absence of sensory input. The theoretical implications of object permanence and its time course concern which of various theoretical approaches to cognitive development hold the most promise for enhancing our understanding of the transformations that take the fetus and build it into the scientist.
- Bower, T. G. R. (1966). The Visual World of Infants. Scientific American, 215, 80–92.Google Scholar
- Bower, T. G. R. (1967). The Development of Object Permanence: Some Studies of Existence Constancy. Perception & Psychophysics, 2, 411–418.Google Scholar
- Bower, T. G. R., Broughton, J. M., & Moore, M. K. (1971). Development of the object concept as manifested in the tracking behaviour of infants between 7 and 20 weeks of age. J Exp Psychol, 11, 182–193.Google Scholar
- Cohen. L. B. (1995, March). How solid is infants understanding of solidity. Paper presented at the meetings of the Society for Research in Child Development. Indianapolis.Google Scholar
- Cohen, L. B. Gilbert, K. M., & Brown P. S. (1996, April 1). Infants’ understanding of solidity: Replicating a failure to replicate. Poster presented at the international conference on infant Studies. Providence.Google Scholar
- Piaget, J. (1954). The construction of reality in the child (Trans: Cook, M.). New York: Basic Books (originally published in French, 1936).Google Scholar