How Infants Learn About the Visual World Johnson 2010

Jun 15, 2011 10:44 PM

Scott Johnson  UCLA

visual world of young infants...  fragmented and unstable...  (rather than coherent objects) its

surfaces that move in unpredictable ways.

3 kinds of learning in infants  to learn know of the visual world:

learning via association

learning via active assembly and

learning via visual-manual exploration;

illustration... figure 1  two girls in a garden.... house hidden by trees.

vision can be bottom-up...  encoding color, luminance, distance, texture, orientation distance,

motion and so forth.

vision also needs top-down know.  that aids interpreetation....

eg  red and blue patches are clothes worn by the girls.

both operate continuously in mature sighted individuals.

r infants restricted to bottom-up processing cuz they lack know?

arguments btnw  LEARNED or CONSTRUCTED  visual world  vs

UNLEARNED or INNATE system of object know. in humans.

2)  CONSTRUCTIVISM vs NATIVISM??

perennial Q of infant epistemology...  is  know.  BUILT-IN???

2.1  Constructivist Theory

Piaget was first.  1954.  hiding a toy under a cover and then observing kids trying to retrieve it.

He positing.... that objects ... early in life... were disconnected forms that moved capriciously and randomly...

there would be no know of objects wihtou know of space....  inseparable.

1161

Objectification was Piaget’s term for knowledge of the self and external objects as distinct

entities, spatially segregated, persisting across time and space, and obeying causal constraints.

Piaget suggested that objectification is rooted in the child’s recognition of her own

body as an independent object and her own movements as movements of objects through

space, corresponding to movements of other objects she sees. This recognition, in turn, was

thought to stem exclusively from exploration of objects via manual activity—that is, object

knowledge is constructed by the child.

But... skilled reaching and grasping is NOT available til after age 4-6 months...

til this time  objects consist of little more than fleeting images.

Active intentional searech behavior marks the inception of objectification.

As the ACTION SYSTEMS DEVELOP  then develps the capacity to interacgt iwth objects and

discover their properties.

PIAGET is widely accepted... BUT...

kids  2-4 months old  can maintains reps of partly or fully occluded objects...

so  (the reasoning goes)  it cannot depend on action systems that they have not yet dvleoped

=>  therefore, it must rely on built-in  innate know.

2.2  NATIVIST THOERY

A central tenet of nativist theory is that some kinds of initial, unlearned knowledge form

a central core around which more diverse, mature cognitive capacities are elaborated

(Spelke, 1990.)

That is, some kinds of knowledge, including concepts of objects as coherent and continuous across occlusion, are

innate. Philosophical discussions of innateness are ancient. Plato and Descartes, for example,

proposed that some ideas, such as concepts of geometry or God or justice

so,  modern nativists focus on LEARNABILITY...  how can infants possibly learn abt hidden objects

unless it's built-in?

Scott J  (author)  questions this assumption and this logic.  he asserts that  infants cud be expoiting

other means of learning abt objects  (and that  object know. is NOT built-in).

3)  developmental change in infants' object perception....

Piaget’s observations led him to conclude that newborn infants have no true concepts of

objects or space (Piaget, 1952). Neonates can discriminate among visible objects and track

their motions, but when objects move out of sight or the baby’s gaze falls elsewhere, previously

encountered objects cease to exist for the infant. The first inklings of object concepts

come from recognition memory, say when infants smile upon mother’s return, beginning a

few months after birth. Knowledge of objects as complete and coherent across gaps in perceptual

contact imposed by occlusion did not come until later, after infants can grasp and

reach objects and thereby come to more fully appreciate properties such as solidity, volume,

and existence independent of the infant. These concepts did not come all at once. Piaget

described one important concept as ‘‘reconstruction of an invisible whole from a visible

fraction,’’ and it was evinced by retrieval of an object from under a cover when only a part

of the object was visible. An appreciation of continued existence despite complete occlusion

was evinced by removal of a obstacle hiding a desired toy, or pulling away a cover from a

parent’s face during peekaboo. These behaviors were not seen consistently until 6–8 months

or so, marking for Piaget the advent of a wholly new set of object and spatial concepts.

Scott J.  disputes Nativist interpretations...  infants r NOT doing percpetual completion.

most resch on infants IS broadly consistent with Piaget.

Infants don't repres.  fully occluded objects til middle of first year of life.

1164

1176  cognit development is constrained by expanding motor control over actions that provide

incr detailed info abt objects and events in the world.

6)  How infants learn abt objects

1181  7) Concluding Remarks

natural scenes are richly structures and have a high degree of redundancy.

by 2 months infants have several hundred hours of viewing experience:  40 hrs per week * 10 weeks = 400 hours.

so, in principle , infants could learn about partly or fully occluded objects just by making associations.

BUT..  studies by Johnson (and students)  indicate that passive experience may be insufficient ...

so may REQUIRE modeling accounts of object perception.  (infants must model objects using active assembly)

ACTIVE ASSEMBLY and visual-manual exploration provide info  to the infant about her own control of an event

and simultan generate multimodal info.

For complex perceptual completion, such as 3D object completion,   the coordination of posture, reaching, grasping, and

visula inspection seem critical:   Only the visual-manual skills involved in generating changes in

object viewpoint - rotating, fingering, and transferring while looking - were related to 3d object completion.

How Infants Learn About the Visual World Johnson 2010

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