Questions: Object Permanence and Sensorimotor Development

Question 1

A 9-month-old infant watches a toy be hidden at location A several times and successfully retrieves it each time. The toy is then visibly moved and hidden at location B. The infant reaches to location A. What does this A-not-B error most directly reveal?

• A. The infant has no understanding at all that objects continue to exist when hidden
• B. The infant's representation of the object is tied to a successful reaching action rather than to a fully flexible model of the object's current location
• C. The infant's vision is not developed enough to track the toy being moved to location B
• D. Object permanence is fully developed by 9 months, so the error must reflect a muscle control problem

Answer: (B)

The A-not-B error shows that at this transitional stage, object representation is action-bound — linked to where successful retrieval was previously performed — rather than flexibly tracking current location. The infant 'knows' the object exists somewhere but perseverates on the learned motor action (reaching to A) rather than updating to B. This reveals that object permanence at 8–10 months is not yet complete: it is knowledge embedded in habitual action, not a fully free-standing mental model.

Question 2

A 3-month-old stares significantly longer at an event that appears physically impossible (a toy seems to pass through a solid wall) but does not reach for a toy hidden under a cloth. What is the best explanation?

• A. The infant is distracted by the impossible event and forgets the hidden toy
• B. Three-month-olds have no object knowledge and the longer looking is coincidental
• C. The infant has implicit perceptual knowledge that objects persist but lacks the action-planning system needed for deliberate search
• D. The infant's arm muscles are too weak to lift the cloth, masking otherwise complete object permanence

Answer: (C)

Violation-of-expectation studies show that infants as young as 3–4 months are surprised by physically impossible events, revealing some implicit representation of object persistence. However, this implicit/perceptual knowledge dissociates from the deliberate action system needed to purposefully search for a hidden object. The gap is not primarily muscular — it is a genuine cognitive dissociation between a representational system that 'knows' something is wrong and a motor-planning system that cannot yet marshal that knowledge into purposeful search.

Question 3

Before approximately 6 months of age, infants have absolutely no knowledge that objects continue to exist when they are out of sight.

• T. True
• F. False

Answer: False

Research using violation-of-expectation paradigms shows that infants as young as 3–4 months display implicit understanding that objects persist — they look longer at physically impossible outcomes involving hidden objects. What they cannot yet do is act on that knowledge through deliberate reaching and searching. Piaget's original claim that object permanence is absent until ~8–9 months underestimated early implicit knowledge by conflating perceptual understanding with the separate capacity for deliberate motor action.

Question 4

Object permanence is considered foundational for language acquisition because both require the ability to mentally represent something — a word or an object — that is not currently present in the environment.

• T. True
• F. False

Answer: True

Object permanence establishes the prototype for symbolic representation: holding a model of something in mind when it is not perceptually present. Language works the same way — every word stands for something that may be absent, and using language requires retrieving a mental representation when the referent is not in front of you. Piaget saw object permanence as the first instance of the general symbolic function that underlies language, deferred imitation, symbolic play, and all later representational thought.

Question 5

What does the A-not-B error reveal about the nature of object permanence at the 8–10 month stage, and why does it show that development is not yet complete?

Model answer: The A-not-B error shows that at 8–10 months, the infant's object representation is still action-bound rather than fully flexible. Through repeated successful retrievals at A, the infant builds a strong action-memory — 'reach to A for the object' — that overrides the updated location when the toy is moved to B. This reveals that the infant does not yet have a fully location-independent, context-free mental model of the object's whereabouts. True object permanence, achieved by 12–18 months, involves a representation that persists and updates regardless of prior actions.

The key distinction is between object knowledge embedded in action ('I know the object is where I last successfully reached') versus object knowledge as a free-standing representation ('I know the object is wherever it currently is'). The A-not-B error locates exactly where the development still has to go: from action-bound knowledge to a flexible, updatable mental model.