LECTURE NOTES FOR CLASS 4
1.) core knowledge
2.) learning to use symbols
3.) symbolic function
1.) CORE KNOWLEDGE—Associated with Elizabeth Spelke
Object constancy, continuity and cohesion, numerosity
States that babies possess core knowledge about several different
domains from birth. Babies are born with a small set of distinct systems
of knowledge that have been shaped by natural selection over
Spelke states that there is strong knowledge that indicates at least 3 core
knowledge systems: (object representation, knowledge of humans and
their actions, and ability to represent numbers)
1. object representation
infants have to recognize 3 features in relation to objects:
i.) object constancy: an object does not change shape or size from
different views of the object. It may appear different from a
different viewpoint, but the actual physical properties of the object
Habituation/dishabituation paradigm is used to test for this ability:
infant is habituated to an object, and then shown the same object from
a different angle so that it creates a different retinal image, or is
shown a new object but displayed in such a way that it projects the
same retinal image.
If the infant possesses size constancy, they will continue habituation
to the same object projected at a different viewpoint, causing a
different retinal image.
If the infant does not possess size constancy, they will dishabituate
when the same object is presented at a different distance, but will
continue to habituate to a different object presented so that it projects
the same retinal image.
In experiments investigating such a thing, infants show the same
pattern as the former.
Oddly enough, older children sometimes fail at object constancy tasks.
For example, many toddlers believe that as planes are in the air, that
they shrink because the further up they go, the smaller the retinal
image projected is. They may believe this because our ancestors never
had to deal with such a situation, so evolutionarily, its quite new.
Disconnect between IMPLICIT and EXPLICIT knowledge
ii.) object continuity and cohesion: objects are seen as cohesive wholes
with distinct boundaries
how is this ability measured experimentally? Show infants an image of a large rectangle occluding a bar. (so that
the middle of the bar is covered, looks like 2 separate bars)
habituate the infants to the image, then show them a picture of a
solid bar. If the infants attention to this image increases, then they
believed that it was in fact 2 separate bars in the image. If their
attention does not increase (they remain habituated) then they
assumed that the rectangle was occluding a solid bar the whole
time. The idea here is that infants are habituated, so its an image
they have seen before.
How do babies respond to these experiments? 4 month olds
habituate, but only for moving stimuli.
Newborns increase their attention to the bar, that suggests that
infants are not likely born with this knowledge.
Concept of “collision” has been investigated as well. Seems to
develop around 2.5 months. These infants increased their looking
time when a toy bug on wheels remained stationary after being hit
by a cylinder rolling down a ramp, or when a bug moved in
absence of contact.
The concept that objects require “support” was also investigated.
At around 4.5 months, somewhat increased awareness and by 6.5
months, awareness that objects require support or they will fall.
Horizontal Decalage: an ability develops at different rates in different
contexts (in terms of this example, the occlusion experiments and
different development rates of surprise at impossible events)
Generally, infants understand that inanimate objects behave in
a continuous and cohesive manner, that contact is necessary
for inanimate objects to move, and objects must be supported
or they will fall.
Principle of Persistence: objects not only exist continuously and
remain cohesive, they also retain their individual properties. No object can undergo
a spontaneous or uncaused change in the course of an event (Baillergeon)
iii.) object permanence: objects are permanent in time and space,
regardless of whether we are in their presence or not. Objects
don’t just disappear because we are no longer looking at them.
Out of sight is literally out of mind
Piaget believed that between 0-4 months, infants understood
objects only through their own actions on them.
At around 8 months, infants can retrieve a completely hidden
A-not-B Object Permanence Task: an object is initially hidden from the infant in one
location, and then later on moved to a second, all done while the child is watching.
The infant will search in the first location, and is often quite surprised not to find the
object they are looking for. (this is the classic paradigm for testing object
permanence) Invisible Displacements: this ability requires the ability to mentally represent an
object. To test this ability, take an object, place it in a container, cover the container,
remove the object, and then show the infant the container. The infant will be
surprised that there is no object, because they were unable to mentally represent it.
Experiments conducted by baillargeon show that infants’ understanding of
the permanence of objects varies with the type of task used to assess it.
How does object representation develop?
Infants need exposure to evidence and different situations
Development is aided by unexpected outcomes. Infants adjust their schemas
and representations to unexpected events
An unexpected events is obviously novel, so the infant will attend to this
event, and this provides a learning experience.
Geary proposed that infants and young children possess skeletal
competencies in 4 abilities related to math:
i.) Numerosity & Ordinality:
Numerosity: The ability to determine quickly the number of items in a set
Ordinality: the basic understanding of more than/less than
Infants display numerosity