Chapter 5

Sensation, Perception, and Action

Modified: 2025-07-03 10:38 AM CDST

I. Perspectives on Sensation, Perception, and Action (p. 139)

• 1. Sensation—process by which sensory information is detected and transmitted to brain
  • a. From birth infants sense their environment (e.g., detect light, sound, odor molecules)
• 2. Perception—interpretation/understanding of sensory input
• 3. Action—motor activities prompted by sensation and/or perceptual information
• 4. Constructivists
  • a. Perception constructed through learning over time (nurture side)
  • b. At birth, equipped with sensory systems
  • c. Need experiential interaction to infer meaning from sensations
  • d. Must view objects from various distances to interpret different retinal images to create association between image and its meaning (e.g., a distant object)

Affordances: ecological theorists such as Eleanor Gibson and James Gibson emphasized the role of affordances. In simple terms, objects offer affordances for actions. For example, a sidewalk confers an affordance for walking comfortably where a narrow path in the woods offers a less comfortable affordance. In contrast, having to hack your way through a jungle offers no affordance at all.

On the test, I may ask you to say why a chair is an affordance (it allows you to sit comfortably). Then, I ask you to compare the affordances offered by a traditional dining room chair and table to the new high top tables and higher chairs found in many restaurants today.

Here is a longish but easy to read chapter on affordances by James Gibson himself.

• 5. Nativist
• a. Born equipped with innate capacities and maturational processes, allowing us to perceive world in meaningful way (nature side)
• b. Infants equipped with sensory systems that are refined through innate plan
• c. Innate understanding of perceptual world (no need for experience to interpret sensory world)
  d. Brain automatically understands that different retinal images give insight into the distance of an object
• e. Current debate on nature–nurture of perception
• f. Constructivist view long popular
• g. New data caused shift toward more nativist perspective
• h. Some declines in sensory and perceptual abilities in later life

II. The Infant (p. 142)

• A. Vision (p. 142)
• B. Basic Capacities (p. 142)
  • 1. Newborn infants can detect brightness and can track slow-moving objects
  • 2. Visual acuity—ability to perceive detail
  • 3. Newborn visual acuity is poor (40 times worse than adult)
  • 4. Improves quickly to about 20/120 on standard eye chart by age 1 month
  • 5. Objects beyond 8 inches are blurry
  • 6. Limited visual accommodation—ability of lens to change shape to bring object into focus
  • 7. Infant color vision
  • 8. Very young infants do see in color
  • 9. Use habituation task to determine color vision
  • 10. Four-month-olds appear to be able to discriminate the basic color categories (red, green, blue, yellow)
  • 11. Newborns have limited color vision due to immature receptors
  • 12. Are faster at detecting stimulus on a background of a different color
• C. Organizing the World of Objects (p. 143)
  • 1. Infants attracted to contour—amount of light–dark transitions
  • 2. Infants attracted to dynamic (moving) vs. static objects

Rovee-Collier's study of infants used operant conditioning to determine if infants were learning.

• 3. Infants prefer object of moderate complexity (e.g., checkerboard)
• 4. Key ability is to be able to separate visual field into distinct objects, even when objects are partially or fully hidden
• 5. Young infants notice irregularities in otherwise well-formed circles or squares
• 6. Use common motion—movement of objects in same direction as a cue to “wholeness” of an object
• 7. Use good form—logical continuation of a line to perceive object’s wholeness
• D. Face Perception (p. 144)
  • 1. Prefer mom’s face to stranger’s face
  • 2. Prefer information in upper visual field (“top-heavy pattern”)
  • 3. Can pick out mom’s face if they have also been exposed to her voice at the same time
  • 4. Infants like to look at what they can see well
  • 5. Around 2 to 3 months, infants begin to explore interior of stimulus (e.g., a face) and appreciate the “whole object” rather than just its contours
  • 6. Young infants visually fixate, while older infants can shift gaze
  • 7. By 2 to 3 months, infants truly perceive a meaningful face and not just an appealing pattern
• E. Depth Perception (p. 145)
  • 1. Very young infants act defensively (blink) when objects move toward their face
  • 2. Size constancy—infant can recognize that object remains same size even though the retinal size changes as object moves away (Exploration Box on infants’ understanding of size constancy)
  • 3. Visual cliff—device used to assess depth perception (Gibson and Walk, 1960)
  • 4. One “shallow” side with checkerboard directly under glass and a “deep” cliff side
  • 5. Young infants will cross both sides, but by 7 months or so, many will no longer cross the deep side
  • 6. Two-month-olds appear to perceive difference between deep and shallow sides (depth) but have not learned to fear drop-offs
  • 7. Fear of drop-offs (and perhaps falling) due to experience in crawling
• F. The Infant as Intuitive Theorist (p. 146)
  • 1. Infants look longer at “impossible” events involving a ball’s motion
  • 2. Ball drops behind a screen and appears to be suspended in midair
  • 3. Innately understand simple laws of physics (object entering right of screen should exit left of screen)
  • 4. Infants appear to be equipped with intuitive theories—naturally possess organized system of knowledge that allows them to make sense of the world
  • 5. Organize knowledge around domains of physics, biology, and psychology
  • 6. Seem to understand causal forces
  • 7. Have innate knowledge of the world and perceive and reason about it in ways similar to adults
• G. Hearing (p. 146)
  • 1. At least as important as vision, and we depend on it to communicate
  • 2. Process of hearing begins when moving air molecules enter the ear and vibrate the eardrum; the vibrations then transmitted to cochlea in inner ear, where they are converted to signals that the brain interprets as sound
• H. Basic Capacities (p. 146)
  • 1. Newborns hear better than they see
  • 2. Are startled by loud noise and turn away
  • 3. Turn toward softer sounds
  • 4. Ability to hear what is going on outside of womb develops as much as 3 months before birth
  • 5. Infants prefer relatively complex auditory stimuli
  • 6. Infants somewhat less sensitive to soft sounds
  • 7. Infants can discriminate loudness, direction, duration, and frequency of sound
• I. Speech Perception (p. 147)
  • 1. Can distinguish phonemes—basic speech sounds—very early in life
  • 2. Can distinguish similar consonant sounds (pa and ba)
  • 3. Can detect difference between vowels a and i from second day after birth
  • 4. Can distinguish normal from deviant (rare) sounds
  • 5. By 3 months, can recognize phoneme spoken by different people
  • 6. Biologically prepared to learn and speak any language as infants
  • 7. By one year, begin to lose sensitivity to speech sounds irrelevant to native language and begin to show increased sensitivity to speech sounds relevant to native language
  • 8. English speaking infants can differentiate between consonants l and r, but Japanese and Chinese infants whose languages do not contain l and r, lose that ability (as do adults in those populations)
  • 9. Language experiences shape neural connections in the areas of the brain optimizing sensitivity to sounds that they have been listening to
  • 10. Infants especially attracted to female voices and can recognize mother’s voice soon after birth
  • 11. Heart rate increases to mom’s voice but not to that of stranger
  • 12. No preference for father’s voice
  • 13. Ability to detect mom’s voice related to exposure to her voice while still a fetus (as demonstrated in Cat in the Hat study)
  • 14. Hearing problems can place at-risk for language and communication problems and need to be treated as early as possible
• J. The Other Senses (p. 150)
  • 1. Taste buds mainly on tongue; sense not well understood but is the result of bud response to chemical molecules
    2. Are four basic tastes (sweet, bitter, sour, salt)
  • 3. Can distinguish tastes (sweet, bitter, sour) at birth, and like sweet
  • 4. Different taste sensations produce different facial expressions
  • 5. Smile when experiencing sweet
  • 6. Purse lips when experiencing bitter
  • 7. Will swallow more amniotic fluid if it contains higher concentrations of sugar
  • 8. Food preferences may be impacted by early tastes that we are exposed to during infancy (Mennella and colleagues research)
  • 9. Infants fed sour-tasting formula preferred sour-tasting items as children
  • 10. Greater exposure to a variety of flavors during infancy may lead to more adventuresome eating habits
  • 11. “Taste gene” may account for variation in taste perceptions
  • 12. Olfaction (sense of smell) result of receptors in nasal passage
    13. Well established at birth
  • 14. Newborns react unpleasantly to vinegar and ammonia
  • 15. Prefer smell of own amniotic fluid (indicates prenatal sense of smell)
  • 16. Breast-fed infants can recognize mother’s milk odor and smell of mom
  • 17. Mothers can recognize their infant by smell and are less repulsed by the smell of their dirty diaper than that of other dirty diapers
  • 18. The somesthetic senses
  • 19. All skin receptors (touch, hot-cold, pain) operating in some form at birth
  • 20. Reflexive touch apparent at birth
  • 21. Tactile sensitivity develops in a cephalocaudal direction
  • 22. Infants explore world via tactile receptors in the mouth
  • 23. Touch can stimulate growth in premature infants and may promote more regular sleep patterns
  • 24. Newborns sensitive to warm and cold
  • 25. Young babies respond to pain (e.g., needle prick)
  • 26. Ethical reasons restrict ability to test infants by inflicting severe pain
  • 27. Pain is responsive to learning
  • 28. Infants with history of heel pricks grimace when nurse preparing heel for pricking
  • 29. Controversy over infant’s ability to sense pain and the use of anesthesia on infants during surgery
  • 30. American Academy of Pediatrics recommends giving local anesthesia to male newborns undergoing circumcisions
  • 31. Breast feeding while experiencing a painful event (vaccination) reduces the behavior signs that an infant is experiencing pain
• K. Influences on Early Perceptual Development (p. 151)
  • 1. All senses are working to some extent by birth, and most perceptual abilities emerge in the first few months
• L. Early experience and the brain (p. 152)
  • 1. Classic study by Hubel and Wiesel on kittens showed deprivation of vision early can lead to permanent loss of vision

Held and Hein (1963) experiment with kittens: Only the active kitten learned to associate movement with experience

• 2. Better to discuss impact of early experience in terms of sensitive periods (rather than critical periods)
• 3. Sensitive period—window of time during which one is more affected by experience and in which there is a higher level of plasticity than in later life
• 4. There may be multiple sensitive periods for vision (one for normal development, one for damage-period when absence of input leads to permanent deficit in some aspect of vision, one for recovery from damage)
• 5. Infants born with congenital cataracts—clouding of the lens—at risk for later visual problems
• 6. The earlier the cataract is surgically corrected or removed (by 10 weeks is optimal), the greater the chance for normal vision (delays can lead to blindness)
• 7. After corrective surgery, infants show normal development in some areas (e.g., recognition of shape of face), but may struggle with certain visual tasks like holistic face processing and recognition of face based on spacing of features
• 8. Maurer and colleagues (2007) suggest sleeper effect of early visual deficits (i.e., lingering effects of lack of early visual input)
• 9. Normal hearing requires normal auditory experience
• 10. Children with significant hearing loss who have cochlear implants struggle to understand signal input that is sent from implant to the brain
• 11. Brain must learn how to interpret information
• 12. Maturation is not enough, as normal perceptual development requires normal perceptual experience
• 13. The infant’s active role
• 14. Infants seek sensory experiences they need for development
• 15. Gibson’s (1988) three phases of exploratory behavior:
• 16. Birth to 4 months: explore by looking and listening
• 17. Five to seven months: voluntary grasping and closer attention
• 18. Eight or nine months: crawl, explore, examine

III.The Child (p. 154)

• A. Learning to Walk: The Coupling of Perception and Action (p. 154)
  • 1. Gross motor skills—skills such as kicking the legs or drawing large circles that involve large muscles and whole-body or limb movements
  • 2. Fine motor skills—skills such as picking Cheerios off the breakfast table or writing letters of the alphabet that involve precise movements of the hands and fingers or feet and toes
  • 3. The emergence of motor skills follows the cephalocaudal principle because the neurons between the brain and the muscles acquire myelin sheaths in a top to bottom direction.
  • 4. There is also evidence of the proximodistal principle, as we watch infants progress from controlling their arms, then their hands, and finally their individual fingers enough to use a pincer grasp, involving only the thumb and the forefinger (or another finger).
• B. Motor Skills and Dynamic Action (p. 155)
  • 1. Dynamic systems theory
  • 2. Grasping and reaching
• C. Physical Behavior (p. 157)
  • 1. Children’s motor development supports their physical behaviors, which are noticeably advanced compared to those of infants and toddlers.
  • 2. Toddlers are capable of controlling their movements in relation to a stationary world, children master the ability to move capably in a changing environment
• D. Integrating Sensory Information (p. 157)
  • 1. Sensory systems like vision and hearing seem to be interrelated early in life
  • 2. Cross-modal perception—recognize through one sense something known through another
  • 3. Needed for game in which someone sees an object that is then put in a bag and person is asked to reach in and pull out the object
  • 4. Infants have some ability to integrated multiple sensory inputs
  • 5. Oral-to-visual cross-modal transfer by 3 months (can identify by sight an object that they have previously mouthed)
  • 6. By 4 to 7 months, can integrate vision and hearing to judge distance
  • 7. Impressions from different senses “fused” in early life, thus infancy is not the “blooming, buzzing confusion” described by James
• E. Advances in Attention (p. 158)
  • 1. Attention—focusing of perception and cognition
  • 2. Attention of infant and young child often “caught” or “captured,” while that of older child is directed
  • 3. Infants are attracted by novelty
  • 4. Orienting system reacts to events in the environment vs. having a focusing system that deliberately seeks out and maintains attention
• F. Longer Attention Span (p. 158)
  • 1. Young children have shorter attention spans
  • 2. Spend less time concentrating on a television program that they like
  • 3. Brain myelination during childhood may positively impact ability to focus attention
  • 4. More selective attention—deliberate concentration on one thing while ignoring another
  • 5. Two-year-olds begin to show ability to focus
  • 6. Increase in focused attention ability between age 31/2 and 4 years
• G. More Selective Attention (p. 158)
  • 1. Selective attention—deliberately concentrating on one thing while ignoring something else
  • 2. Infants are not good at controlling their attention

Having owned five Chevrolet trucks built from 1949 to 1976 I quickly and selectively attend to trucks of that era when I see them parked or on the road. Interestingly, my wife does not attend to them :-)

• H. More Systematic Attention (p. 158)

• 1. With age, children better at systematic perceptual searches (e.g., more detailed and exhaustive visual searches)
• 2. Children’s visual searches slower and less efficient than adults
• 3. Six-year-olds more systematic searchers than 4- and 5-year-olds

IV.The Adolescent (p. 159)

• A. Attention (p. 159)
  • 1. Adolescents vs. children
  • 2. Adolescents better able to sustain attention (longer attention spans)
  • 3. May be tied to brain myelination that speeds transmission of neural impulses
  • 4. Adolescents more efficient at ignoring irrelevant stimuli
  • 5. Learning likely to be thrown by distractors
  • 6. Adolescents better at dividing attention (switching between two stimuli)
• B. Vision and Hearing Challenges (p. 160)
  • 1. The modern world poses some risks to maintaining healthy senses.
  • 2. To reduce some of the effects of spending hours in front of a computer screen, there are some fairly simple recommendations
  • 3. The most common outcome of noise exposure is tinnitus, or ringing sounds in one or both ears that can last for days, weeks, or indefinitely.
  • 4. 40% of teens report experiencing tinnitus in conjunction with listening to music with earbuds
  • 5. 15% of teenagers have some level of hearing loss, with minority youth, males, and those from low socioeconomic backgrounds disproportionately affected by hearing loss.
• C. Refining the Connection between Perception and Action (p. 162)
  • 1. Professional athletes have skills that go beyond what we see on the field, court, or pool
  • 2. Some scholars believe that perception and action are coupled at birth, with young infants equipped with the rudimentary skills to act upon their perceptions
• D. Cultural Variation (p. 162)
  • 1. Perceptual preferences differ from culture to culture
  • 2. People from different cultures differ little in basic sensory capacities, such as the ability to discriminate degrees of brightness or loudness
  • 3. Although there may be some differences in sensory thresholds, the bigger differences seem to be in people’s perceptions and interpretations of sensory input.

V.The Adult (p. 164)

• A. Sensory thresholds—the threshold for a sense (low levels of stimulation) to be detected (p. 164)
• B. Vision (p. 164)
  • 1. Sensory and Perceptual Change
    • a. Usually gradual and minor, beginning in early adulthood
    • b. Raised sensory thresholds—threshold for detection of stimuli (e.g., hearing a faint tone, detecting a slight odor)
    • c. Declines in perceptual abilities
    • d. Have more difficulty interpreting sensory information (e.g., trouble searching visual scene)
    • e. Perceptual declines vary by individual and may be compensated for
  • 2. Basic pattern of change
    • a. Most people will not lose sight with age
    • b. Nine out of 10 will need corrective lenses
    • c. One in four will have cataracts—clouding of lens
  • 3. Process of vision
    • a. Light enters through cornea and passes through the pupil and lens before being projected upside down on the retina
    • b. Image is relayed via the optic nerve to the brain for processing
    • c. Pupil of eye automatically adjusts to lighting conditions
    • d. Lens automatically changes shape to keep image in focus
    • e. Visual system normally at peak performance in adolescence and young adulthood
  • 4. Changes in the pupil
    • a. Pupil becomes smaller
    • b. Transitions from dark to light tough
    • c. Reading low-contrast word in dim lighting is tough
    • d. Difficult to read menu in dimly-lit restaurant
    • e. Tougher to recover from glare (e.g., coming out of dark theater into bright sunlight)
    • f. Slower to react, resulting in poor dark adaptation—process of eyes adapting to darkness
  • 5. Changes in the lens
    • a. Lens denser, less flexible, and yellows
    • b. Thickening lens leads to presbyopia—difficulty seeing close objects clearly
    • c. May compensate by moving object further from eye
    • d. Middle-aged cope by getting reading glasses
    • e. Distance vision fairly stable in adulthood
    • f. Older females show greater visual decline than males
    • g. More susceptible to falling
    • h. Loss may mean serious threat to independence
    • i. Uncorrected vision can lead to serious decrease in quality of life in old age
    • j. Cataracts—clouding of the lens
    • k. Leading cause of visual impairment in old age
    • l. Life-long heavy exposure to sunlight a risk
    • m. Can be removed surgically, improving vision and preventing blindness
  • 6. Retinal changes
    • a. Age-related macular degeneration—damage to cells responsible for central vision
    • b. Vision blurry and fades from central of field of vision
    • c. Now leading cause of blindness in adulthood
    • d. No effective treatments
    • e. Decrease in field of vision (loss of peripheral vision)
    • f. Negative impact on tasks like driving (Exploration Box on aging drivers)
    • g. Retinitis pigmentosa—loss of light-sensitive cells and peripheral vision
  • 7. Group of hereditary disorders
    • a. Can appear in childhood
    • b. Cannot be cured, but some promising new research indicating that vitamin A treatment might slow progress of the disease
    • c. Glaucoma—increased fluid in eye damages optic nerve and peripheral vision
    • d. More common after age 50
    • e. Key is to prevent before it occurs using eyedrops or surgery
• C. Attention and Visual Search (p. 168)
  • 1. Adults are better able to control their attention (e.g., attend to angry face if told a threat may be present)
  • 2. Divided and selective attention tasks harder for older adults
  • 3. On visual search task, the more distractors, the harder the task
  • 4. More difficulty in inhibiting responses to irrelevant information
  • 5. Reduction in efficiency of visual search skills but can be improved with practice
  • 6. Greatest difficulty on novel and complex tasks
  • 7. Fewer problems when given clear explanations
• D. Hearing (p. 169)
  • 1. Hearing impairment and old age
  • 2. Hearing impairments three times as prevalent as visual impairments in older adults
  • 3. 90% of those over age 65 have at least mild hearing loss (which will become progressively worse)
• E. Basic Capacities (p. 169)
  • 1. Most age-related problems occur in inner ear
  • 2. Some degeneration of cochlear cells and neurons leading to the brain with age
  • 3. Presbycusis—noticeable loss of sensitivity to high-frequency sounds
  • 4. Trouble hearing child’s high voice, flutes in an orchestra, and some high-frequency consonants
  • 5. High-frequency sounds need to be louder to be heard
  • 6. Loss both age-related, due to experience (e.g., loud noise), and related to one’s sex (males seem to show more detectable loss at earlier ages)
• F. Speech Perception (p. 170)
• 1. Older adults have more difficulty understanding conversations
• 2. Problems worse under poor listening conditions (e.g., loud background noise)
• 3. Age-related declines in auditory sensitivity play a role, but so do cognitive declines (e.g., attention skills)4. Auditory perception more difficult if tasks are novel and complex
• G. Aging of the Other Senses (p. 171)
  • 1. Taste
    • a. General decline in taste sensitivity
    • b. Some older adults report that food tastes bland
    • c. Ability to identify food by taste declines with old age
    • d. Some loss of taste may be side effect of taking medications
    • e. Less production of saliva also negatively impacts ability to taste
    • f. “Sweet tooth” does not decline with age
  • 2. Smell
    • a. Ability to detect odors declines in old age
    • b. Difference between age groups small
    • c. Greater decline in ability to detect pleasant vs. unpleasant odors
    • d. Healthy adults maintain sense of smell better
    • e. Taste loss related to loss of sense of smell and cognitive factors (e.g., ability to remember and name what was tasted)
    • f. Use of flavor enhancers and related increase in food consumption may be a way to improve health in elderly
• H. Changes in the Somesthetic Senses (p. 171)
  • 1. Detection thresholds for touch increases and sensitivity is gradually lost from middle childhood
  • 2. Older people less sensitive to temperature change
  • 3. Older people less likely to report weak levels of stimulation as painful, yet are not more sensitive to stronger pain
• I. The Adult in Perspective (p. 172)
  • 1. Declines in vision and hearing most important and nearly universal
  • 2. Some ability to compensate for loss, but loss cannot be eliminated
  • 3. Sensory impairments may impact basic tasks of living (e.g., walking)
  • 4. Most older adults with sensory impairments are living full quality lives

Back to Main Page

Back to TAMUT Start Here Page