Introduction to Psychology, 7th Edition, Rod Plotnik
Module 5: Sensation
Module 5
Sensation
Introduction to Psychology, 7th Edition, Rod Plotnik
Module 5: Sensation
Sensations
Sensation is direct input from sense organs
– Vision
– Hearing
– Vestibular system
– Taste
– Olfaction
– Touch
Introduction to Psychology, 7th Edition, Rod Plotnik
Module 5: Sensation
EYE: VISION
•
Structure and function
1. Gather and focus light
2. Absorb and transform light waves into electrical
impulses
– process called transduction
Introduction to Psychology, 7th Edition, Rod Plotnik
Module 5: Sensation
p95 EYE
Introduction to Psychology, 7th Edition, Rod Plotnik
Module 5: Sensation
EYE: VISION
• Structure and function
– Vision: 7 steps
• Image reversed/Light waves
• Cornea
• Pupil
• Iris
• Lens
• Retina
Introduction to Psychology, 7th Edition, Rod Plotnik
Module 5: Sensation
EYE: VISION
• Structure and function
– Cornea
• bends and focuses light waves into a narrower
beam of light
– Pupil
• allows light waves to pass into the eye’s interior
Introduction to Psychology, 7th Edition, Rod Plotnik
Module 5: Sensation
EYE: VISION
• Structure and function
– Iris
• controls the amount of light entering the eye
– Lens
• bends and focuses light waves into an even
narrower beam
Introduction to Psychology, 7th Edition, Rod Plotnik
Module 5: Sensation
EYE: VISION
• Structure and function
– Retina
• extremely sensitive to light
• begins the process of transduction by
absorbing light waves
Introduction to Psychology, 7th Edition, Rod Plotnik
Module 5: Sensation
p96 RETINA
Introduction to Psychology, 7th Edition, Rod Plotnik
Module 5: Sensation
EYE: VISION
• Visual pathways: Eye to brain
– Optic nerve
– Primary visual cortex
– Visual association areas
Introduction to Psychology, 7th Edition, Rod Plotnik
Module 5: Sensation
p97 VISUAL SYSTEM
Introduction to Psychology, 7th Edition, Rod Plotnik
Module 5: Sensation
EYE: VISION
• Visual pathways: eye to brain
– Optic nerve
• nerve impulses flow through the optic nerve as
it exits from the back of the eye to the brain
• the exit point is the “blind spot” (Why don’t you
notice the blind spot?)
• the optic nerves partially cross and pass
through the thalamus
• the thalamus relays impulses to the back of the
occipital lobe in the right and left hemisphere
Introduction to Psychology, 7th Edition, Rod Plotnik
Module 5: Sensation
Leading a person who is blind
•
•
•
•
Offer your assistance
Keep the person on the leader’s left
Allow the person to take your arm
Give clear/brief/accurate information
People who are blind respond well to intelligence
Demonstrate veering
Introduction to Psychology, 7th Edition, Rod Plotnik
Module 5: Sensation
Visual Impairment and the Artificial Eye
Introduction to Psychology, 7th Edition, Rod Plotnik
Module 5: Sensation
EAR: AUDITION
• Measuring sound waves
– decibel: unit to measure loudness
– threshold for hearing:
• 0 decibels (no sound)
• 140 decibels (pain and permanent hearing
loss)
Introduction to Psychology, 7th Edition, Rod Plotnik
Module 5: Sensation
Introduction to Psychology, 7th Edition, Rod Plotnik
Module 5: Sensation
EAR: AUDITION
– Outer ear function
– pick up sound waves and then send them
down the auditory canal
Introduction to Psychology, 7th Edition, Rod Plotnik
Module 5: Sensation
EAR: AUDITION
• Outer, middle, and inner ear
– Inner ear
• contains two structures sealed by bone
– cochlea: involved in hearing
– vestibular system: involved in
sensing the position of the head,
keeping the head upright, and
maintaining balance
Introduction to Psychology, 7th Edition, Rod Plotnik
Module 5: Sensation
CHEMICAL SENSES (CONT.)
• Tongue
– Five basic tastes
• sweet
• salty
• sour
• bitter
• umami: meaty-cheesy taste
Introduction to Psychology, 7th Edition, Rod Plotnik
Module 5: Sensation
CHEMICAL SENSES (CONT.)
• Taste buds
– shaped like miniature onions
– receptors for taste
– chemicals dissolved in saliva activate taste buds
– produce nerve impulses that reach areas of the
brain’s parietal lobe
– brain transforms impulses into sensations of taste
Introduction to Psychology, 7th Edition, Rod Plotnik
Module 5: Sensation
CHEMICAL SENSES (CONT.)
• Smell, or olfaction
– Olfaction
• called a chemical sense because its stimuli are
various chemicals that are carried by the air
• Function of olfaction
– receptors, through transduction, transform
chemical reactions into nerve impulses
Introduction to Psychology, 7th Edition, Rod Plotnik
Module 5: Sensation
p107 OLFACTORY BULB
Introduction to Psychology, 7th Edition, Rod Plotnik
Module 5: Sensation
CHEMICAL SENSES (CONT.)
• Smell, or olfaction
– Sensations and memories
• nerve impulses travel to the olfactory bulb
• impulses are relayed to the primary olfactory
cortex
• cortex transforms nerve impulses into olfactory
sensations
• Can identify as many as 10,000 different odors
• we stop smelling our deodorants or perfumes
because of decreased responding
• called adaptation
Introduction to Psychology, 7th Edition, Rod Plotnik
Module 5: Sensation
CHEMICAL SENSES (CONT.)
• Smell, or olfaction
– Functions of olfaction
• one function: to intensify the taste of food
• second function: to warn of potentially
dangerous foods
• third function: elicit strong memories; emotional
feelings
Introduction to Psychology, 7th Edition, Rod Plotnik
Module 5: Sensation
Smell Memory
Introduction to Psychology, 7th Edition, Rod Plotnik
Module 5: Sensation
TOUCH
• Touch
– includes pressure, temperature, and pain
Introduction to Psychology, 7th Edition, Rod Plotnik
Module 5: Sensation
p108 SKIN
Introduction to Psychology, 7th Edition, Rod Plotnik
Module 5: Sensation
TOUCH (CONT.)
• Receptors in the skin
– skin
– hair receptors - when first bent
(after being bent=sensory adaptation)
– free nerve endings – temperature and pain
– Pacinian corpuscle – vibrations
Somatosensory cortex (parietal lobe)
– transforms nerve impulses into sensations of touch
temperature, and pain
Introduction to Psychology, 7th Edition, Rod Plotnik
Module 5: Sensation
PAIN
• What causes pain?
– pain: unpleasant sensory and emotional
experience that may result from tissue damage,
one’s thoughts or beliefs, or environmental
stressors
– pain results from many different stimuli
Introduction to Psychology, 7th Edition, Rod Plotnik
Module 5: Sensation
p112 BRAIN PAIN
Introduction to Psychology, 7th Edition, Rod Plotnik
Module 5: Sensation
PAIN (CONT.)
• How does the mind stop pain?
– gate control theory of pain
– nonpainful nerve impulses compete with pain
impulses in trying to reach the brain
– creates a bottleneck or neutral gate
– shifting attention or rubbing an injured area
decreases the passage of painful impulses
– result: pain is dulled
Introduction to Psychology, 7th Edition, Rod Plotnik
Module 5: Sensation
PAIN (CONT.)
• Endorphins
– chemicals produced by the brain and secreted in
response to injury or severe physical or
psychological stress
– pain reducing properties of endorphins are similar
to those of morphine
– brain produces endorphins in situations that evoke
great fear, anxiety, stress or bodily injury as well
as intense aerobic activity