Transcript Perception of Three Dimensional Space

Chapter 6
Early Cognitive
Foundations: Sensation,
Perception, and Learning
Dr. Pelaez
Sensation and Perception
• Sensation - the process by which sensory
receptor neurons detect information and
transmit it to the brain.
• Perception - the interpretation of the
sensory input; cognitive awareness of what
you sense.
Ex. You sense a particular smell and have
the ability to identify what you are
smelling.
Early Controversies About Sensory
and Perceptual Development
• Nature versus Nurture- Empiricist philosophers believed
that an infant was a tabula rasa (blank slate) who must
learn to interpret sensations. By contrast, nativist
philosophers took the nature side of the nature/nurture
issue, arguing that many basic perceptual abilities are
innate.
• Enrichment versus Differentiation- Both these theories
argue that there is an objective reality out there to which
we respond.
Early Controversies cont…
Enrichment vs. Differentiation
• Enrichment Theory - Theory specifying that we
must add to sensory stimulation by drawing on
stored knowledge in order to perceive a
meaningful world.
-Sensory information is often fragmented and
confusing, therefore we must pull on prior
knowledge in order to construct meaning.
Early Controversies cont…
• Differentiation Theory - Argues that sensory
stimulation provides all we need to interpret our
experiences. This implies that our main task is to
simply to detect distinctive features in our
environment.
• distinctive features - characteristics of a stimulus
that remain constant; dimensions on which two or
more objects differ and can be discriminated.
Making Sense of the infant’s sensory
and perceptual experiences
• The Preference Method- is a simple procedure in
which at least two stimuli are presented
simultaneously to see whether infants will attend
more to one of them than the other(s).
• The Habituation Method- is the process whereby a
repetitive stimulus becomes so familiar that responses
initially associated with it no longer occur.
Cont……….
• Evoked Potentials- another way of determining
what infants can sense is to present them with a
stimulus and record their brain waves.
• High-Amplitude Sucking- provides infants with a
special pacifier containing electrical circuitry that
enables them to exert some control over the
sensory environment.
Infant Sensory Capabilities
• Vision- it may be the least mature of the
newborn’s sensory capabilities. Changes in
brightness will elicit a subcortical pupillary reflex,
which indicates that the neonate is sensitive to
light. Babies can also detect movement in the
visual field and are likely to track a visual
stimulus with their eyes as long as the target
moves slowly. Newborn infants are likely to track
faces than other patterns.
• Visual acuity- a person’s ability to see small
objects and fine detail. Neonates’ distance vision
is about 20/600 (very blurry). Improves rapidly
during the first few months
Vision cont…
Color perception
• By 2-3 months babies can discriminate all
basic colors.
• By 4 months they can group colors of
slightly different shades into the same
basic categories.
Infant Sensory Cont…
• Hearing- using the evoked potential
method, researchers have found that soft
sounds that adults hear must be made
noticeably louder before a neonate can
detect them. In the first few hours of life
infants may hear about as well as an adult
with a head cold.
Hearing cont….
– Reactions to Voices-Research by Anthony
DeCasper and his associates reveals that
newborns suck faster on a nipple to hear a
recording of their mother’s voice than a
recording of another woman.
– Reactions to Language- Not only do babies
attend closely to voices, but they are also able
to discriminate basic speech sounds, called
phonemes, very early in life.
Hearing cont…
– Consequences of Hearing Loss- Otitis media, a
bacterial infection of the middle ear, is the most
frequently diagnosed disease among infants and
preschool children. As a result,
developmentalists have feared that youngsters
with recurring infections may have difficulties
understanding others’ speech, which could
hamper their language development and other
cognitive and social skills that normally emerge
early in childhood.
Infant Sensory Cont…
• Taste and Smell- Infants are born with some very
definite taste preferences. For example, they
apparently come equipped with something of a
sweet tooth because both full-term and premature
babies suck faster and longer for sweet liquids
than for bitter, sour, salty, or neutral solutions.
Newborns are also capable of detecting a variety
of odors, and they react vigorously by turning
away and displaying expressions of disgust in
response to unpleasant smells.
Infant Sensory Cont…
• Touch, Temperature, and Pain- Receptors in the
skin are sensitive to touch, temperature, and pain.
Sensitivity to touch clearly enhances infants’
responsiveness to their environments. Newborns
are also quite sensitive to warmth, cold, and
changes in temperature. Do babies experience
much pain? Apparently so, for even 1 day old
infants cry lustily when pricked by a needle for a
blood test.
Perception of Three Dimensional
Space:
• Steropsis - a convergence of visual images of the
two eyes to produce a singular nonoverlapping
image that has depth. (3 month olds do not exhibit
this ability)
• Pictorial cues - depth and distance cues including
linear perceptive, texture gradients, sizing,
interposition, and shading, that are monocular.
Perception of Three Dimensional
Space cont…
• Visual looming - the expansion of the image of an
object to take up the entire visual field as it draws
very close to the face.
*One month olds may respond to a looming object
by blinking defensively.
• Size constancy - the tendency to perceive an
object as the same size from different distance
despite changes in the size of it’s retinal image.
Perception of Three Dimensional
Space cont…
• Kinetic cues - created by movements of objects or
movements of the body; provide important
information for the perception of forms and spatial
relations.
*Inferences about real size among 4 month olds are
likely to be accurate if the infants can watch the
object approach and recede.
• Visual cliff - an elevated platform that creates an
illusion of depth; used to test depth perception in
infants.
Perception of Three Dimensional cont...
– Development of Depth Perception- Eleanor
Gibson and Richard Walk developed an
apparatus they called the visual cliff to
determine whether infants can perceive depth.
The visual cliff consists of an elevated glass
platform divided into two sections by a center
board. On the “shallow” side, a checkerboard
pattern is placed directly under the glass. On
the “deep” side, the pattern is placed several
feet below the glass, creating the illusion of a
sharp drop-off, or a “visual cliff.”
Visual Perception in Infancy
• Perception of Patterns and Forms- Recall Robert
Fantz’s observations of infants in his looking
chamber: Babies only 2 days old could easily
discriminate visual patterns.
– Early Pattern Perception (0 to 2 Months)babies prefer to look at whatever they see well,
and the things they see best are moderately
complex, high-contrast targets, particularly
those that capture their attention by moving.
Perception of Patterns cont…
– Later Form Perception (2 months to 1 year)Between 2 and 12 months, the infant’s visual
system is rapidly maturing. He or she now sees
better and is capable of making increasingly
complex visual discriminations. He or she is
also organizing what he or she sees to perceive
visual forms. The most basic task in perceiving
a form is to discriminate that object from its
surrounding context (i.e., other objects and the
general background).
Intermodal Perception
-The ability to use one sensory modality to
identify a stimulus or pattern of stimuli that
is already familiar through another
modality.
- Are the Senses Integrated at Birth?- The
senses are apparently integrated early in
life.
-Not confirmed to be present at birth but
becomes more accurate over time possibly
due to the maturation of the senses.
Intermodal Perception cont…
– Explaining Intermodal Perception- The findings
that the senses are integrated at birth and that at
least some intermodal matching is possible in
the first few months seems most consistent with
the differentiation theory of perception.
Differentiation theorists propose that the
distinctive features that characterize sensory
input are detectable by more than one sensory
channel.
Basic Learning Process
•
1.
2.
Learning - a relatively permanent change in behavior
that results from one’s experiences or practice.
Once the individual learns they now think, perceive or
reacts to their environment in a new way.
The change is clearly the result of a person’s experiences
- that is, attributable to repetition, study, practice or
observations the person has made, rather than to
hereditary or maturational processes or to physiological
damage resulting from injury.
•Learning cont…
3. The change is relatively permanent. Facts,
thoughts, and behaviors that are acquired and
immediately forgotten have not really been learned;
and temporary changes caused by fatigue, illness or
drugs do not qualify as learned responses.
Basic Learning Processes
• Learning is one of those deceptively simple
terms that are actually quite complex.
– Habituation: Early Evidence of Learning
and Memory- the process by which we
stop attending or responding to a stimulus
that is repeated.
Classical Conditioning (Ivan Pavlov)
- a type of learning where an initially neutral
stimulus is repeatedly paired with a meaningful
nonneutral stimulus so that the neutral stimulus
come to elicit the response originally made only to
the nonneutral stimulus.
Process: a neutral conditioned stimulus is repeatedly
paired with an unconditioned stimulus that always
produces an unconditioned response. After several
parings the CS alone will elicit the response which
is now called a conditioned response. *
Operant Conditioning (B.F. Skinner)
-a form of learning where freely emitted acts
become either more or less probable
depending on the consequences they
produce.
Key Concepts
• Reinforcer - any consequence that strengthens a
response by making it more likely to occur in the
future.
• Positive reinforcer - an event that, when
introduced following a behavior,makes that
behavior more probable in the future.
• Negative reinforcer - also strengthen behaviors,
but the behavior is strengthened because
something unpleasant is removed after the
behavior occurs.
• Punisher - any consequences of a behavior that
suppresses the responses and decreases the chance
that it will reoccur.
Key Concepts cont…
• Positive punishment - occurs when an unpleasant
consequence is added to a situation following
behavior.
• Negative punishment - occurs when something
pleasant is taken away from a situation following a
behavior.
Observational Learning
-results from observing the behavior of other people.
Almost anything can be learned by watching or
listening to others.
• Encoding - the process by which external
stimulation is converted to a mental
representation.
• Deferred imitation - the ability to reproduce the
actions of a model at some point in the future.
Develops rapidly during the second year. *