Chapter 5- Motor, Sensory, and Perceptual Development

Dynamic systems view (3)

• Skills are assembled for acting on the environment based on perceptions

• Infant’s actions are solutions to their goals

• Issues in development: the role of the active child

Reflexes (2)

• Genetically built-in, automatic reactions to stimuli

• Are NOT learned

Sucking reflex (3)

• Stimulation: object touching infant’s mouth

• Response: infant sucks automatically

• Developmental pattern: disappears after 3-4 months

Moro reflex (3)

• Stimulation: sudden stimulation such as a loud noise or being dropped

• Response: startles, arches back, throws head back, flings out arms and legs then rapidly closes them to center of body

• Disappears after 3-4 months

Grasping reflex (3)

• Stimulation: palms touched

• Response: grasps tightly

• Weakens after 3 months, disappears after 1 year

Gross motor skills (5)

• Large muscle movements

• Complex process that requires sensory input

• Culture variations ← the role of experiences

• With locomotion comes independence & additional development

• Boys > girls in gross motor development in early childhood

Fine motor skills

Finely-tuned movements

Importance of posture (2)

• Posture control is the foundation required to develop gross motor skills

• Within weeks, babies learn to voluntarily control posture

Pincer grip (2)

• Grabbing with thumb & pointer finger

• By the end of the first year of life

Palmer grasp

Grabbing with the whole hand (palm)

Peak physical performance age range

19-26 years

Sensation

Information transmitted through sensory receptors (eyes, ears, nostrils, tongue, skin)

Perception

The interpretation of what is sensed

Ecological view (2)

• States people directly perceive information that exists in the world

• Perception brings people in contact w/ the environment so they can interact with & adapt to it

Studying infants’ perception: Visual preference paradigm

Looking preferably to one side or another

Studying infants’ perception: Attention to sound

Change in frequency of sucking in response to sound

Studying infants’ perception: Orienting responses

Looking towards a stimulus (sight or sound)

Studying infants’ perception: Habituation & dishabituation (2)

• Habituation: decreased responsiveness to a stimulus after repeated presentations

• Dishabituation: recovery of a habituated response after a change in stimulation

Infant visual perception: Visual acuity (3)

• It’s difficult for infants to see far away b/c nerves, muscles, and lens of the eyes are still developing

  • Estimated 20/240 vision at birth

  • Improves to 20/40 by 6 months

Infant visual perception: Face perception (2)

• Infants prefer faces vs other shapes

• Young infants systematically scan human faces

Infant visual perception: Color vision (2)

• Early on (4-8 weeks), some color discrimination

• Preferences - ~4-5 months

Infant visual perception: Perceptual constancy (4)

• Sensory stimulation is changing, but perception remains constant

• Suggests perception goes beyond sensory info provided

• Implies perception of the world is stable

• By 3 months, size & shape constancy

Infant visual perception: Depth perception - visual cliff (3)

• Depth perception: 6 months

• 6-12 month olds would not crawl over cliff

• 2-4 month olds have different heart rates when on deep vs shallow side of visual cliff

Changes in visual perception in adulthood (6)

• After the early adult years, visual acuity declines

• Reduced color differentiation and ability to see peripherals

• Eye accommodation decreases the most from 40-59 yrs

  • Accommodation of the eye: The eye’s ability to focus and maintain an image on the retina

  • Presbyopia: loss of accommodation

• Significant declines in visual functioning: 75-85+ yrs

Hearing - when can a fetus begin to hear? (3)

• Hearing starts during last 2 months of pregnancy

• Can hear immediately after birth, but sensory threshold is higher than adults’

• Developmental changes: perception of loudness, pitch, and localization

Infant hearing: Localization (2)

• Ability to determine where a sound came from

• Newborns can tell general location, but skill becomes more proficient by 6 months

Fetal learning

Hearing their mother read while in the womb

Hearing changes in adulthood (2)

• Hearing can start to decline by 40 yrs, especially sensitivity to higher pitches

• Hearing impairment doesn’t usually become an impediment until late adulthood

Do infants have smell and taste preferences at birth?

• Newborns can differentiate odors

• Sensitivity to taste is present before birth

Intermodal perception (3)

• Integrating from 2 or more modalities (e.g. seeing & hearing)

• Present in newborns and becomes sharper over the first year of life

• Most perception is intermodal

Nature & nurture: Nativists and empiricists approaches

• Nativist view: perceptual/motor development is inborn & innate

• Empiricist view: stronger role of experience placed on perceptual/motor development

Perceptual-motor coupling (2)

• Perception & action are coupled

• Must perceive in order to move and move in order to perceive