Perceptual & Motor Development

Chapter 5: Perceptual & Motor Development

I. Sensing the Environment

  • Newborns' sensory systems are all functioning, but some are more developed than others (e.g., touch and smell are more developed than vision).
  • Methods for assessing sensory capabilities:
    • Preferential looking: More time looking at a stimulus indicates a preference. Newborns show preferences for upright faces and schematic faces.
    • Habituation/Dishabituation: Present Stimulus 1, leading to an increase in B.P. and heart rate. Responses decline with familiarity. Present Stimulus 2; if B.P. and heart rate increase, it suggests the infant can discriminate S2 from S1.
    • High-Amplitude Sucking: Establish a baseline and measure the rate of sucking in response to stimuli.

Hearing

  • Not fully developed at birth.
  • 3-day-olds can turn in the general direction of sound but have trouble localizing the source.
  • Prefer human speech, which is slow, clear, and high-pitched.
  • Infants prefer consonant tones (e.g., a major 5th) to dissonant ones (e.g., a minor 2nd or an augmented 4th).

Vision

  • Newborns are very nearsighted.
  • Abilities include:
    • Scanning their surroundings.
    • Perceiving patterns and distinguishing among forms.
    • Showing a preference for faces.
    • Distinguishing mother’s face.
  • Newborns respond to light and track moving objects with their eyes, but perceive few colors and concentrate on edges.
  • 3-month-olds concentrate on the interior of faces and are better at perceiving color.
  • Perception of faces is shaped by perceptual narrowing.
    • 6-month-olds: Generalists who recognize other-race and other-species faces just as well as same-race faces.
    • 9-month-olds: Specialists with superior recognition for same-race faces.
  • Children with ASD scan faces in an atypical manner.
    • Griffin et al. (2021) meta-analysis of 112 studies: On average, 80% of ASD individuals perform worse than typical individuals on tests of face recognition.

Depth Perception

  • Visual (optical) expansion: The visual image of an object increases as the object comes toward us. By 1 month, infants will blink at expanding image.
  • Binocular disparity: Cues about distance based on the differing views of the two eyes. Develops by 4 months.
  • Pictorial (monocular) cues: Cues about distance that can be perceived by one eye alone (e.g., relative size, texture gradient). Develops by 6 or 7 months.
  • Visual cliff studies show that children as young as 6 weeks react with interest to differences in depth. At 7 months, they show wariness of the deep side of the cliff.

Taste and Smell

  • Newborns prefer sweet tastes and smells (e.g., breast milk).
  • Averse to sour, bitter, and salty tastes, and foul odors.

Touch

  • Helps stimulate early physical growth.
  • Newborns are sensitive to pain.
  • They explore objects with hands/mouth.

Intermodal Perception

  • The ability to perceive an object or event by more than one sensory system simultaneously.
  • Intersensory redundancy theory: Infants learn best when stimuli are presented to multiple sensory modes (e.g., watching someone play an instrument: sight + sound).
  • McGurk effect: Occurs when visual information influences the way we hear a phoneme. For example, hearing “ba” misheard as “va” when lips appear to be saying “va”. 5-month-olds experience this illusion.

II. The Growth of Attention

  • Processes that allow people to control input from the environment and regulate behavior.
    • Orienting network: Determines which stimuli will be processed.
    • Alerting network: Prepares the infant to detect and respond to incoming stimuli.
    • Executive network: Shifts attention from one stimulus to another; ignores distracting stimuli.
    • Example of Executive Network: The ability to play a board game without getting distracted by other toys
    • Development of selective and sustained attention (Kannass & Colombo, 2007):
      • Graph indicates performance relative to distraction condition: None, Intermittent, Continuous for 3.5-year-olds and 4-year-olds.

ADHD

  • Two main types:
    • Inattentive: Trouble staying focused; easily distracted.
    • Hyperactive/impulsive: Interrupts, intrudes; can’t wait for turn.
    • Often resulting in academic and social problems.
  • Causes:
    • Genetic factors: Monozygotic twin concordance rates are 55%.
    • Research suggests impairment in the connection between the frontal lobes and the limbic system.
    • Diagram: Shows brain activation differences between a person without ADHD and a person with a history of ADHD in the frontal and limbic regions.
  • Sex Differences:
    • Prevalence: 3-7% of Canadian children (using DSM-V criteria).
    • Boys are 4 times as likely to be diagnosed.
    • Girls are more often diagnosed with inattentive ADHD.
    • Controversy: Some “symptoms” may reflect behavior that’s normal for boys of a young age.
  • Treatment:
    • Stimulant medication (increases frontal lobe activity).
    • If regulated, improves attention, academic performance, and peer relations for about 70%.
    • Best outcomes for children given medication combined with behavioral therapy.

III. Motor Development

  • Gross Motor Skills: Involve large muscles of the body and make self-locomotion (crawling, walking, etc.) possible
    • Crawling Styles:
      • Hands-and-Knees
      • Bear Crawl
      • Tummy Crawl
      • Bottom Scooter
  • Motor milestone
    • Progression of Locomotion
      • Walking alone
      • Standing alone
      • Walking with assistance
      • Hands-and-knees crawling
      • Standing with assistance
      • Sitting without support
      • Corresponding ages in months on the graph go from 3 months to 21 months
  • Gross Motor Skills
    • Dynamic Systems Theory
      • Motor development stems from confluence of several factors:
        • Increase in strength
        • Balance / posture
        • Perceptual skills
        • Motivation
  • Gross Motor Skills milestones by age:
    • 2-3 years: can run, kick a ball, climb on furniture
    • 3-4 years: can ride tricycle, stand on one foot
    • 4-5 years: can skip, throw ball overhand, run smoothly
    • 5-6 years: ride bike without training wheels; gallop, skip, jump
  • Fine Motor Skills: Involve the development and coordination of small muscles
    • Reaching and grasping skills:Poor at 3 months; adept at 6-9 months
    • Manual dexterity skills:By 12 months, can use thumbs in opposition to fingers
  • Fine Motor Skills
    • 2-yr-olds: use spoon & fork; turn book pages
    • 3-y-o’s: feed self well;
    • 4-y-o’s: draw person; dress self well
    • 5-y-o’s: print letters; tie shoes