1. Sensation and Perception
CP Psychology
CHAPTER 5
Sensation and Perception
Section 5Q2
Mr. Freccia, NHS
Glencoe Publishers

2. The Human Senses
7 Senses: Vision … Hearing …Taste-Smell …Touch/Skin Sensation …Vestibular … Kinesthetic
Vision: Light enters the eye through the Pupil, is focused (and inverted) by the Lens, and projected onto the Rods and Cones of the Retina where it is converted to neural impulses and sent through the Optic Nerve (blind spot) to the brain

3. Sensation & Perception

4. Sensation & Perception
Rods: Very light sensitive, sense black/white, useful for night vision
Cones: Concentrated opposite to lens, color sensitive, requires more light
Receptors in the Human Eye
Cones
Rods
Number
Location in
retina
Sensitivity in
dim light
Color sensitive?
Yes
Low
Center
6 million No
High
Periphery
120 million

6. Sensation & Perception
Trichromatic (three color) Theory
three different retinal color receptors
red
green
blue

7. Sensation & Perception
Color Deficiency (color blindness)
Some or all of the cones do not function properly (genetic)
Color Blindness Test! (Click)

8. Sensation & Perception
Binocular Fusion: The combination of the eye’s two separate images into one
Retinal Disparity: The difference between the images sensed by each retina
Stereopsis: The ability to see depth as a result of retinal disparity

9. Sensation & Perception

10. Sensation & Perception
Hearing: Vibration is converted to neural impulses which travel along auditory nerve
Decibels measure sound wave intensity (loudness)
Pitch measures high/low frequency (in-tune)

11. noise not only affects hearing it also affects our behavior (stressor)
Noise & Stress
noise not only affects hearing it also affects our behavior (stressor)
noise is especially stressful when unanticipated or uncontrollable
A 10 decibel increase results in a ten-fold increase in sound

13. Sensation & Perception1
time 10
times
100
1000 32 64
128
256
512
1024
2048
4096
8192
16384
Frequency of tone in waves per second
Low
Pitch
High
Amplitude (loudness)
required for
perception relative to
20-29 year-old group
Older people suffer neural hearing loss for higher frequencies/low amplitude
20-29 years old
30-39 years old
40-49 years old
50-59 years old
60 years and up

14. Sensation & Perception
Time delay between ears receiving sound waves contributes to locating its origin
Reaches ear later
Reaches ear sooner

15. Sensation & Perception
Taste Sensations
taste is a “chemical” sense..sweet, sour, salty, bitter
Smell
smell is also a “chemical” sense
precisely how olfactory receptors work is a mystery
receptors recognize odors individually
Sensory Interaction
principle that one sense may influence another
the smell of food significantly influences its taste

16. Sensation & Perception
Smell/Taste: Chemicals activate receptors which send signals along olfactory nerve
Receptor cells in
olfactory membrane
Nasal
passage
Olfactory
bulb
nerve

17. Sensation & Perception
Olfactory Cortex
Located on temporal lobe near taste cortex
Linked to areas of memory storage which helps explain smell triggered memories
Taste Cortex
Olfactory Cortex

18. Sensation & Perception
Bitter
Sour
Salty
Sweet

19. Sensation & Perception
Skin Sensations (Touch)
pressure is the only skin sensation with identifiable receptors
relationship between warmth, cold, pain remains a mystery
when warm/cold receptors are activated together you feel “hot”

20. Sensation & Perception
Vestibular Sense: Three semicircular canals in the ear regulate the sense of balance
Kinesthetic Sense: (Kinesthesis) Receptors in muscles, tendons, and joints assist with posture and balance