Lecture 3 Perceptual and Motor Development Flashcards
what is Sensation?
sensory receptor neurons detect
information and transmit it to the brain
begins when a stimulus in the environment
activates receptors in the sensory organs (eyes, ears, nose, mouth,
and skin). Receptors are neurons that convert the stimulus into
signals that are sent to the brain. For example, light activates
electromagnetic receptors in the eyes that then transmit information
to the brain about the visible environment. Similarly, airborne
molecules activate chemoreceptors in the nose that signal about
odors
what is Perception?
the psychological process of
organizing and interpreting sensory input
Infants’ sensory organs enable them to detect
and discriminate among the sights, sounds, tastes, smells, and
touches of their environments. Infants then organize and interpret
sensory information in the process of perception.
what are two early theories
- Gestalt theory of perception
- Ecological theory of perception
what is gestalts theory of perseception?
principles or laws of human perception that describe humans spontaneous and natural organziation of visual stimuli into meaningful patters such as perceiving objects as whole
what is the ecolgical theroy of perception?
elenor and Jame gibson highligh the evolutionary foundations of perception and connections between perception and action
whats the perception-action feedback loop
refers to
the continuous cycle that connects perception and action as people
perceive, act, and adjust their actions in response to an everchanging
environment
A: baby looking, baby reahces
B: bay looking, reaches, touches, grasps and manipulates
(A) Depiction of a simple perceptionaction
feedback loop.
B) An example of a perception-feedback loop in which an infant looks
at a toy, reaches, touches, grasps, and manipulates the toy. The feedback from each step in
the sequence leads to new actions and alters the infant’s perceptions as what the baby
sees and touches continually changes.
whats an Affordances for Action
An individual’s interpretation of which actions
are possible, and which are not possible based
on their perceptions
– E.g., When infants determine that a flat surface
offers the opportunity for walking
how do we test infants
- Preferential-looking tests
- Habituation-recovery tests
- Contingent reinforcement studies
what are Preferential Looking tests
(Fantz, 1960s):
– Present 2 stimuli, measure attention to both
– If infant pays more attention to one stimulus, that means…
she or he:
* Notices the difference
* “Prefers” one stimulus over the other
what are Habituation-Recovery tests
– Present 1 stimulus until infant becomes “bored”
– Present new stimulus
– If infant pays more attention to the new stimulus,
s/he:
* Notices the difference
involve presenting infants with a stimulus until they habituate or decrease their attention to the stimulus. When researchers then present infants with a new
stimulus, infant attention might recover or rebound to its initial level. Infants’ rebound of attention is thought to offer a window
how can we measure attention?
– Overt behaviour
– Physiological measures
what are Contingent-Reinforcement Studies
- Operant conditioning
- Infants increase a specific behavior in
response to certain stimuli to obtain reward
– E.g., infants’ sucking behaviors in response to
hearing their mothers’ voice
Researchers test whether
infants increase a specific behavior, such as sucking a pacifier or turning their head, in response to certain stimuli, such as hearing the
mother’s voice. Contingent reinforcement is sometimes used in conjunction with habituation-recovery to examine decreases and
then increases in the rewarded behavior. For example, an infant
might learn to suck on a pacifier to hear music. After some time, the infant habituates to the music and the sucking subsides. At that point, researchers introduce a new stimulus, such as the sound of birds chirping. Infants’ rebound in sucking indicates that they candiscriminate between the old and the new sounds.
whats Infant Vision?
- The most studied behavior in infant perception
- Vision is not simply seeing. It includes:
– actively looking
– tracking objects and people
– recognizing familiar, loved faces
whats Visual acuity
( the ability to see fine detail)
– How sharp is babies’ vision?
explain the time line of The Development of Acuity
- Newborns: 20/600
- Legally blind!
-They can see objects
about a foot away best - By 6 months: 20/100
- By 12 months: 20/50
- By 6 years: 20/20 (adult
level)
whats Tracking motion
neworns moving thier head in respionse to moving stimuli
- Jerky eye movements until 2 months of age, with further
development through 4 or 5 months
– Anticipatory eye movements: 6 months - Facilitates social interactions
whats contrast sensitivity
the minimum
difference in brightness between an image and its background that
infants can perceive
whats Good continuation:
A Gestalt principle of organization that claims a
natural tendency for individuals to view objects or
stimuli as continuous or whole
- Gestalt psychologists asserted that infants, like adults, perceive a
coherent visual world, and so will infer for example, that two pieces
of a rod sticking out from either end of a box in front of the rod form
a single rod. That’s because infants perceive an object as whole when
part of the object is occluded (hidden) by another object, what is
referred to as good continuation.
provide a timeline of depth perception
- Kinetic Cues (looming or
approaching):
– 1 month of age - Stereopsis (binocular vision)
– 4 months of age - Sensitivity to pictorial
(monocular) cues
– 6-7 months of age
Depth
whats Depth perception
refers to the ability to perceive vertical distance
from a top surface or space to a bottom one. (Note: distance refers to
the space between two points, which can be horizontal or vertical).
Without depth and distance perception, we would be unable to move
about without bumping into things or recognize the dangers of a
train platform, balcony, or mountain cliff.
whats binocular
cues,
Depth and distance are signaled by cues from two eyes
whats monocular cues
Depth and distance are signaled by cues from from one eye
what % of Young infants view faces of their
waking time
25-50%
new borns perfer..
their mother’s face
whats Perceptual narrowing
A developmental process characterized by a
diminished ability to distinguish among less
frequently-encountered stimuli
* Own-species vs. other-species; own-race vs. other-race
Contexts of Face Perception in adults
Can distinguish humans
but not monkeys
Contexts of Face Perception Newborn-6 mths
Can distinguish both
humans and monkeys
Contexts of Face Perception after-6 mths
Can no longer distinguish
between monkeys
What can babies perceive?
Audition
* Fetuses can hear in the last 3 months before birth
* Newborns hear quite well, but:
– Sounds must be louder for newborn to hear
– Sounds in the range of human voices are heard best
whats Absolute threshold:
minimum sound level of stimulus
to detect a sound
whats Relative threshold
minimum difference in loudness
or pitch to discriminate between sounds
Do newborns prefer hearing speech more
than non-speech sounds?
– YES!
– Mother’s voice over stranger’s voice
– “Baby talk” over adult-directed speech
– Native language over different languages
* Their auditory system is biased to attend to a
socially significant stimulus!
exmpain the biological foundation for music perception
- A biological foundation for music perception
– Newborn brains respond to variations in music (pitch,
pitch changes, rhythm)
– Infants share the strong preferences adults have for
some musical sounds over others
whats Perceptual narrowing:
a diminished
ability to distinguish among stimuli because of a lack of experience
with them. Faces associated with a person’s sex and race illustrate
the phenomenon of perceptual narrowing.
provide a timiline for preceptual narrowing
By 4 months, infants prefer music of their own culture;
by 12 months, difficulty discriminating rhythmic
structures of other cultures
explain the History behind William Thierry Preyer
- English physiologist who
systematically
documented changes in
his own son’s motor skills
from birth to 3 years of
age - Proposed a common and
universal sequence of
motor development
across species
explain History behind Gessell & Motor Milestones
- American child
psychologist who tracked
the motor behaviors and
physical growth of 107
infants between 4 to 56
weeks
whats Maturation
Maturation is a genetically determined process that
controls and preserves the order of behaviors and
skills as children develop
Gesell based claims of maturation on….
“co-twin” study
on stair climbing in identical twin girls (Gesell & Thompson,
1929)
– Trained twin exceeded non-trained twin, but the other twin learned faster and
caught up
– Claim: when maturationally ready, learning is faster
whats Dynamic systems
considers the many
interacting forces that influence infants’ motor
skills, beyond “top-down” brain explanations
- exmaple: the stepping reflex ( a phenomenon in which newborns
demonstrate spontaneous, coordinated “stepping” movements by
lifting one leg and then the other when held over a surface—presents
a starting point for understanding how something as seemingly
simple as body weight can affect the expression of a behavior)
What is Posture?
- The position in which a person holds their
head and body, and ability to stably maintain
the body’s position
– Stable posture facilitates action
– Unstable posture impedes action - Critical to all motor skills (e.g., sitting,
reaching, standing)
explain sitting
Must maintain posture
* Muscles in the neck, torso, legs, and hips to
help with balancing (e.g., Adolph & Berger, 2006)
* Supported sitting helps promote infants’ later
sitting ability
* In North America, infants begin to sit
independently around 5-7 months
Practice with crawling permits infants to..
estimate accurately if different surfaces are safe
or risky to crawl across
provide a time line for Locomoting: Cruising and Walking
- 7 to 13 months: infants use furniture and other
supports to pull up to a standing position and then
“cruise” sideways while holding on (Bly, 1994) - Different than walking: Relies on hands for support
(no awareness of legs) - 1 year old: infants let go of supports and begin
walking independently - With experience, infants gain proficiency in walking
(step length, speed, and width)
What drives the development of motor
abilities?
- Maturational Viewpoint
- Unfolding of a genetically programmed series of events
– Experiential Viewpoint - Opportunities to practice are important
old parenting practices
Parenting practices:
– 1992 “Back to Sleep” Campaign to prevent SIDS
– This has delayed the onset of rolling over and
crawling
* Tummy time
Infants growing up in different parts of the world are
exposed to different opportunities to practice such
motor skills as sitting and walking (e.g., Adolph, Karasik,
& Tamis-LeMonda, 2010)
