Piaget's conclusions about infant cognition based on systematic observations have powerfully influenced
     the field of infancy research; many developmentalists disagree with Piaget.
     Assumptions about the Nature of Infants
          Sensorimotor period - infants' awareness of the world is limited to what they know through
          sensory processes and motor acts. Based on motor and mental activity.
     Processes of Developmental Change
          Two key mechanisms:
               Adaptation - process by which children change to function more effectively in their
               environment, occurs due to the joint product of two processes.
                  a.Assimilation - involves applying an existing capability without modifications to various
                    situations.
                  b.Accommodation - the process of modifying an existing strategy or skill to meet a new
                    demand of the environment.
               Infants' skills reflect underlying cognitive structures called schemes (e.g., sucking, grasping,
               looking), which are sensorimotor during infancy.
               The theory also includes a mechanism to keep cognitive development moving forward,
               equilibration, which is a self-regulatory process producing increasingly effective adaptations.
               When the infant functions adaptively, he is in a state of equilibrium (balance) but sometimes
               an infant will encounter new skill situations and will experience disequilibrium.
     Sensorimotor Stages
        1.The sensorimotor period is divided into six substages.
        2.Three important points to remember:
               Piaget was describing the most advanced level of performance for each stage.
               The age ranges are only approximate. What is important is the sequence of stages.
               Piaget's stages are only one way of describing infant cognitive development.
        3.Stage 1: Reflexes (Birth to 1 Month) - infants operate on the basis of reflexes. These built-in
          responses are the building blocks for later development.
        4.Stage 2: Primary Circular Reactions (1 to 4 Months) - A circular reaction is a behavior that
          produces an interesting event (initially by chance) and so is repeated. Infants begin to show
          primary circular reactions, involving their own bodies (e.g., thumb sucking).
        5.Stage 3: Secondary Circular Reactions (4 to 8 Months) - Infants produce secondary circular
          reactions, in which they actively experience the effects their behaviors have on external objects
          (association between behaviors and sensory consequences).
        6.Stage 4: Coordination of Schemes (8 to 12 Months) - infants put actions together into goal-directed
          chains of behavior, coordination of schemes. Can anticipate future consequences of motor
          actions.
        7.Stage 5: Tertiary Circular Reactions (12 to 18 Months) - As with primary and secondary circular
          reactions, a tertiary circular reaction begins when some action accidentally leads to an
          interesting sensory consequence. But rather than just repeating the same behavior, the infant
          "experiments" and varies it in a purposeful, trial-and-error way.
        8.Stage 6: Beginnings of Representational Thought (18 to 24 Months) - marks the start of the
          transition from sensorimotor to symbolic or representational thought. The child becomes
          capable of deferred imitation and is able to start to solve certain types of problems mentally
          without having to go through the physical actions involved.

Challenges to Piaget's Theory

     Piaget's descriptions of infant behavior were quite accurate but his explanations have been challenged
     regarding the following:
        1.Timetable for the emergence of cognitive skills. He underestimated the skills of infants at various
          ages. He credited infants with a skill only when it was well developed.
        2.Existence of qualitatively distinct developmental stages. Simultaneous progress of skills is
          assumed with Piaget's theory. Yet, there is inconsistency in infant's achievements (Piaget called it
          dècalage). Many argue that cognitive development is the acquisition of separate skills.
        3.Range of innate abilities. Piaget argued that infants are born only with a set of reflexive behaviors
          while others, neo-nativists, argue that babies have a relatively broad range of innate abilities and
          knowledge (specific learning mechanisms to guide development).
        4.Source of infants' cognitive limitations. Abilities are limited by sensorimotor cognitive structures and
          lack of representational abilities. Others argue that it is a limit in their working memory.

Infants' Understanding of the Physical World

     Infants develop increasingly flexible strategies for exploring and manipulating their environment. They
     must construct this knowledge over time. Neo-nativists contend that a basic understanding of physical
     reality is built into babies at birth or is developed shortly thereafter.
     Concept of Objects
        1.Object permanence is the understanding that objects continue to exist even when they are out of
          sight. Piaget's account of this ability is as follows:
               In stages 1 and 2, infants appear to not have any understanding of object permanence.
               Stage 3 infants show that a partial view of something is now enough to remind them of the
               whole (need perceptual cues of existence of objects).
               Stage 4 infants will search for hidden objects, yet show the A-not-B error.
               Stage 5 infants will search for a hidden object wherever it disappeared last from sight, yet do
               not understand invisible displacements.
               Stage 6 infants have a mature understanding of object permanence.
        2.Further Research on Infants' Understanding of Objects
               Earlier ages for reaching object permanence milestones have been noted. An age limitation
               of Piaget's tasks is the need for manual search and memory. Some have used habituation, as
               discussed in Chapter 4, to minimize search and memory constraints. Less stringent criteria
               are used in research presently.
        3.Perception of Partially Hidden Objects
               Some, using variants of a habituation technique, have shown that 3.5- to 4.5-month-olds show
               some knowledge of object properties when the objects are partially hidden.
        4.Evidence of Object Permanence in Stage 3 Babies
               4- to-8-month-olds have some understanding of object permanence (research by Baillargeon
               is presented). Object permanence seems to develop before the ability to mentally represent a
               hidden object's size and location.
        5.Explaining Infants' Search Behavior
               Infants may have trouble with the means-ends behavior required to search for hidden
               objects-lifting a cloth to allow retrieval of a toy under it.
               The A-not-B error may be due to memory limitations.
               The A-not-B error may be due to the inability to inhibit the reinforced response.
        6.Summarizing research on the object concept
               Piaget was accurate about the sequence in which the object concept is acquired but
               underestimated the rate of acquisition.
               Basic understanding of object permanence emerges sometime between 3 and 5 months of
               age.
               Object search behavior lags considerably behind object-related looking behavior.
               The use of research methods that catch more subtle signs of understanding than Piaget's
               methods are still emerging.

Infantile Amnesia

Why is it that most of us can't remember anything specific
that happened to us before the age of three?

If infants do not remember specific events, how can what
happens to them affect their development?
 
There are a number of explanations for the phenomenon
of infantile amnesia:

        1. The simplest (and least developmental)
explanation is that the memories have simply decayed and
have been lost because of the passage of time.
 
This possibility is easily disposed of, however, since the
lack of memories before age three is the same for an
8-year-old or an 80-year-old;
the lower boundary of autobiographical memory does not
move upwards as we age.
 
     2. A second possibility is that the memories are stored
but are inaccessible for some reason.

Freud claimed that they are repressed because they are too
painful or too sexually charged for us to deal with as
adults.
He also suggested that repressed early memories are
replaced by "screen memories" of ordinary events that are
less threatening.

Another possible reason for the inaccessibility of early
memories is that they are stored in a form that is not
interpretable to us after we acquire language or that does
not fit the categories of adult thought.
 
     3.  A third possibility is that the memories were never
stored in the first place, for either biological or
psychological reasons.

Infant's neurological development may be inadequate to
support long-term memory storage.
 
Several specific neurological explanations have been
proposed, including incomplete myelination in the
association areas of the cortex and immaturity of
dendrites.

One of the most promising neurological explanations
centers on the development of the hippocampus, an area
of the brain involved in the formation of new memories
and in long-term memory consolidation.
 

Psychological explanations for storage failure centered on
the idea that memories must be verbally encoded to be
available for future retrieval, a process unavailable to
pre-linguistic children.

This explanation is unlikely.

There is ample evidence that not all memories are verbally
mediated, even in adulthood.

On the other hand, Nelson (1990) offers a
social-functional explanation of childhood amnesia,
presenting evidence that shared memory talk with adults
provides the conditions for establishing an
autobiographical memory system.
 
Another approach to infantile amnesia holds that events
can be stored in two different kinds of memory system:
one (implicit memory) system is available from early
infancy and can produce behavioral changes without
awareness of memory, whereas the other system,
explicit memory, develops due to maturation of the
hippocampus.

Newcombe and Fox (1994) examined explicit and implicit
memory by studying 9- and 10-year-olds' recognition of
faces of former preschool classmates.
Yes-no recognition (the measure of explicit memory) of
former classmates' faces was at low levels but was
significantly above chance.

Skin conductance data (the measure of implicit memory)
showed similarly low but above-chance recognition.

Children with little explicit memory for classmates were
as likely to show differential skin conductance responding
to faces of former classmates as were children with higher
explicit memory scores.

These findings suggest that infantile amnesia may not
always involve complete loss of encoded information.

Some researchers hoping to understand infantile amnesia
have examined adults with amnesia.

Even after suffering profound disruptions in their ability
to form consciously accessible long-term memory traces,
amnesics have nevertheless been found to show
behavioral changes based on prior experience
(Newcombe & Fox, 1994).

Research suggests that infants are certainly capable of
short-term memory from very early in life.

There is also evidence of long-term memory spanning
periods of up to a week or two, but even that long-term
memory may not be comparable to the very long-term
memory involved in autobiographical memory.

By necessity, the type of memory retrieval demonstrated
for very young infants is recognition, not recall--infants
can be shown to recognize an object or situation by
their behavior in response to it, but it is harder for them to
provide evidence of recall of something that is absent,
since they can't speak (but see Bauer's research).

There is evidence from diary studies that 7- to
11-month-old infants do use recall memory in day-to-day
situations, but it is not clear if they are recalling specific
events in the sense that adults and older children do
in thinking about the past.

Children under 3 show good evidence of what Piaget
called "memory in the broad sense" (Tulving's semantic
memory), but seem to make less use of "memory in the
specific sense" (episodic memory).
 

In other words, they show good understanding and recall
of routines and recurring events, which can be mentally
represented in the form of scripts.

(Katherine Nelson refers to them as generalized event
structures.)

They are less likely to recall specific events from the past,
however--and it is of course recall of specific events from
the past that makes up autobiographical memory.

Developmentalists often assume that events in infancy
influence the course of later development.

If infants do not remember specific events, how can what
happens to them affect their development?

At some level, individual continuity must rest on a base of
memory, though perhaps not specific, episodic memories
of the past.

Daniel Stern has suggested that continuity of experience
consists in part on the development of a self-history.

For infants, self-history depends on motor, perceptual, and
especially affective memory.

Infants develop expectations about future interactions
from their previous experiences with their caregivers.

If these previous experiences could not be stored
in some way, it would be difficult for them to have an
influence on future behavior and development.

Stern suggests that an infant's interactive experiences are
generalized into representations very similar to Nelson's
generalized event structures
--what Bowlby calls internal working models of the self
and others.

It is these general representations that influence future
development, not memories of specific episodes.