Physical World Flashcards
Piaget, 1954
first researcher to examine whether infants, like adults, hold expectations about physical events
Analyses of infants’ responses in various object-manipulation tasks led him to conclude that, during the first year of life, infants possess very little physical knowledge, and take a long time to develop it
Object Permanence task Hide a toy and the child fails to recognize the object still exists – doesn’t look for it
- Doesn’t take into consideration memory and physical ability, young children can’t remember and reach.
Testing Physical Understanding
Occlusion - object becomes or at least partly hidden behind a nearer object or occluder
Support - object becomes supported by another object (
Containment - object is placed inside a container - the contained object is hidden because it is lowered inside, not behind, the container
Present infants with 2 scenarios: Possible scenario (follows laws of physics) Impossible scenario (breaks the laws of physics) Infants tend to look longer at impossible events - Suggests they have knowledge of the correct law
Baillargeon (1987) reports the 3.5 month olds look longer in the experimental (impossible) than in the control (possible) condition. They conclude that these children understand object permanence
Innate concepts Theory
Spelke (1994)
Infants form rules about physical events that allow them to predict the likely outcome of events
These rules are based on innate core knowledge
Rules become more sophisticated with development
Core principles:
Continuity (objects exist and move continuously in time and space)
Solidity (two objects cannot exist in the same space at the same time) constrain from birth infants’ interpretations of physical events.
Theory theory - Gopnik & Meltzoff
No innate premise
Whilst interacting with the physical world, children develop theories as to how the world works
Theories allow children to make predictions about new evidence, interpret the evidence and explain the evidence.
Babies start to make guesses about how the world works At birth, infants already draw some inferences about human behaviour that go well beyond the direct evidence of their senses (Meltzoff & Gopnik, 1996)
Support Events Baillargeon, Needham & DeVos (1992)
A box was held in one of several positions relative to the platform, and the infants judged whether the box should remain stable when released.
3mths - infants have formed an initial concept of support. Any contact is deemed as support.
- 5 to 5.5 months – Revise and elaborate initial concept. Take into account the type of contact between the box and the platform. Infants now expect the box to remain stable on but not against the platform.
- 5 months - consider the amount of contact, expect the box to remain stable if a large but not a small portion of its bottom surface rests on the platform.
- 5 month olds looked longer at the partial-contact for the 15% but not the 70% condition. 5.5-6 month olds looked equal amounts at both events in both conditions.
- 5 months of age, infants begin to attend to the proportional distribution of the box; they realize that a box can be stable only if the proportion that rests on the platform is greater than that off the platform
Adult like knowledge does not exist at birth, however Innate theorists would argue that core knowledge is and this enables the child to acquire more complex knowledge
Occlusion
Luo, 2000; Lou & Ballargeon, 2001
At 2.5 months of age, infants appear to follow a simple “behind/not-behind” rule when predicting the outcomes of occlusion events: they expect an object to be hidden when behind an occluder, and to be visible otherwise.
Infants do not take into account information about the relative sizes of the object and occlude. Adult like knowledge is not present.
Innate theorists claim that with development infants revise and elaborate the initial concept, resulting in accurate predictions over time - Rules become more sophisticated over time
3 months of age - expect the object to become visible when passing behind two screens that are connected at the top by a short strip. 3.5 months of age -consider the relative heights of the object and screen. When the object passes behind two screens that are connected at the bottom by a strip, infants expect the object to become partly visible if it is taller
Occlusion
Spelke, 1992
2.5 mnth – Shown two barriers then they were hidden. A ball was rolled behind the screen. The screen was revealed to show either the ball resting against the first or second barrier. Infants looked reliably longer at the second barrier condition - suggesting that they believed that the ball continued to exist after it became hidden, and realised that it could not roll to the second barrier when the first barrier blocked its path. - Continuity concept
Detect continuity and Solidarity with no variables
Hespos & Baillargeon, 2001 (Containment)
2.5 month – object was lowered either behind (behind-container condition) or inside (inside-container condition) a container; next, the container was moved forward and to the side, revealing the object behind it. - looked at object inside-container condition for longer
Suggested that the infants (1) believed that the object continued to exist after it disappeared from sight (Continuity principle) (2) remembered whether it had been lowered inside or behind the container; (3) realised that the object, could not pass through its closed sides and thus had to move with it when moved (Solidity principle)
New Variables
If infants possessed core principles shouldn’t they be able to detect all violations? Some continuity and solidity violations are detected as early as 2.5 months, others are not detected until much later. Infants younger than 9.5 months are not surprised when an object placed inside a transparent container is not visible (Luo & Baillargeon, 2004).
Infants notice their current theory cannot predict, and then searching for the conditions that can explain the outcome (Baillargeon, 2004)
When an infants visual system has matured at about 7 months they can detect transparent surfaces, and realise that objects can be visible through surfaces (Lou & Baillargeon, 2001)
7 months are puzzled when they can see the object though a transparent sheet. Their knowledge of occlusion specifies that an object should be hidden when placed behind a larger occluder. By 7.5 months of age, infants have formed a new condition-outcome rule: they now expect objects to be hidden when behind larger occluders that are opaque but not transparent – Learnt not innate
A not B errors
Babies at 9 months have object permanence
Hide toy in box A repeatedly – then hide it in box B, where will the child look? - B the place where it disappeared.
Sometimes A - Sometimes objects reappear where they were before e.g. child drops her teddy bear, mum picks it up (while child is asleep) teddy ends up back in the toybox
Based on a WRONG theory of the world which requires further experience of the properties of objects
Carey and Spelke (1996, pp. 521-2): There are other explanations that trace A-not-B errors to maturational changes in the brain structures promoting means/end planning and the inhibition of competing responses
Some evidence cannot be explained by theory theory:
under certain circumstances 9-month-olds will make A-not-B errors even when the object at B is still clearly visible.
Conclusion
Height and transparency are identified separately in each event category. Infants identify the variable height at about 3.5 months in occlusion events, at about 7.5 months in containment events, (Baillargeon & DeVos, 1991;Hespos & Baillargeon, 2001
Therefore infants expectations are event-specific.
However 2.5 month olds posses event-general principles of continuity and solidity (Spelke, 1994; Spelke et al, 1992). It’s suggested that general principles are innate and event specific principles are acquired though development. Young infants should succeed in detecting violations in any event category, as long as it only involve spatial and temporal info they can represent. Older children should fail to detect violations in an event when it involves a variable they haven’t come across before for that category. Infants fail to identify height as a variable until 3.5 months in occlusion events, and 7.5 for containment events (Baillargeon & DeVos, 1992;Hespos & Baillargeon, 2001)
