Download Smell, Taste, Pain, Hearing and Psychophysics

Chapter 7
Smell, Taste, TOUCH &
Hearing
Sensation and Perception
 SENSATION: the psychological experience associated
with sound, light, or other simple stimulus and the initial
information-processing steps by which sense organs and
neural pathways take in stimulus information from the
environment
 PERCEPTION: the recognition, organization, and
meaningful interpretation of sensory stimuli
Breakdown of the Sensory Systems
 PHYSICAL STIMULUS: that in the environment that
activates the sense organs
 PHYSIOLOGICAL RESPONSE: pattern of electrical
or chemical activity that occurs as a result of the
stimulus
 SENSORY EXPERIENCE: subjective sensation and
perception experienced by the person
Each Sensory System Has Distinct
Receptors and Neural Pathways

SENSORY RECEPTORS:
specialized structures
(cells or tips of neurons)
that respond to physical
stimuli

SENSORY AREAS: areas of
the brain’s cerebral cortex
that receive and analyze
input from the body’s
senses
Sensory Transduction Concepts
Transduction and Coding for the
Sense of Smell
 Physical stimulus:
ODORANTS
 Sensory Receptors:
olfactory receptor
cells
 Location: mucous
membrane of the
olfactory epithelium
Differences Among People in
Olfactory Sensitivity
 Women are more sensitive to
smells than men
 Sensitivity decreases with age
 Genetic and environmental
influences: ANDROSTENONE &
differentiation learning
Discriminating Among Individuals
by Smell
 Smell plays a role in mother-infant bonding
 Involved in mate selection (major histocompatibility
complex)
 PHEROMONES: a chemical that is released by an animal
and that acts on other members of the species to
promote some specific behavioral or physiological
response

Vomeronasal Organ
Anatomy and Physiology of Taste
Sensory receptors: taste receptor cells
Location: Tongue (Taste buds), roof of
the mouth, entrance of the throat
Five Primary Tastes
An Evolutionary Account of
Taste Quality
What is edible (safe) and what is not
(poisonous)?
Sour taste due to bacterial decay; bitter
taste due to toxic compounds
Women and children are most sensitive
to bitter
Neural Pathways for Pain
 Physical stimuli:
 pressure
 vibration (to judge an
object’s roughness)
 temperature
 pain (events that
cause tissue damage)
Touch Sensory Receptors
A-delta fibers
C fibers
 PIC of skin surface
Sound as a Physical Stimulus
 AMPLITUDE  LOUDNESS (Decibels)
High Amplitude
Low Amplitude
 FREQUENCY  PITCH (Hertz)
Low Frequency
High Frequency
How the Ear Works
The Inner Ear
Tectorial
membrane
Deafness and Hearing Aids

Conduction deafness
occurs when the ossicles
fail to move and transmit
vibrations to the inner ear

Sensorineural deafness
results from damage to
the hair cells or auditory
neurons

A COCHLEAR IMPLANT
may be used to transmit
electrical impulses directly
to the cochlea by means
of an implant
Von Bekesy (1961)