Sensation a process by which our sensory receptors and nervous system receive and represent...
-
Upload
theodora-daniel -
Category
Documents
-
view
226 -
download
2
Transcript of Sensation a process by which our sensory receptors and nervous system receive and represent...
Sensationa process by which our sensory receptors and nervous system receive and represent stimulus energy
(sensory stimuli > transduction to neural message > brain)
Perceptiona process of organizing and interpreting sensory information, enabling us to recognize meaningful objects and events
Our sensory and perceptual processes work together to help us sort out complex processes
Bottom-Up Processinganalysis that begins with
the sense receptors and works up to the brain’s integration of sensory information
Top-Down Processing information processing
guided by higher-level mental processes
as when we construct perceptions drawing on our experience and expectations
All 4s will apply each term to a children’s story or movie…
Psychophysicsstudy of the relationship between physical characteristics
of stimuli and our psychological experience of themLight- brightnessSound- volumePressure- weightTaste- sweetness
Using sensory details, imagine and describe how you experience the following stimuli:•Sunshine through your window at 5:45 a.m•Loud classical music during class•Sour Patch Kids while watching a movie•A large hammer in your hand
Absolute Threshold minimum stimulation needed to detect a particular stimulus
50% of the time (Ex: passing car)
In partners or trios, come up with another example to explain to the class
Difference Thresholdminimum difference between two stimuli required for
detection 50% of the time (Ex: flower color)
just noticeable difference (JND)
In partners or trios, come up with another example to explain to the class
Signal Detection Theorypredicts how and when we detect the presence of a faint
stimulus (signal) amid background stimulation (noise)
assumes that there is no single absolute threshold because:
detection depends partly on person’s:
Experience – Expectations -Motivation -Level of fatigue
Kellan leaves work at 10 am. After stopping at the bank, he pulls out onto the highway to head home. Right as he turns onto the highway, a car full of 6 men dressed in masks rush into the bank behind him. Using Signal Detection Theory, predict why he may or may not notice. Person #1- Create an explanation and Person #4 create an alternative. Be ready to share in 3 minutes.
Subliminal
When stimuli are below one’s absolute threshold for conscious awareness
(Advertisements…)
0
25
50
75
100
Low Absolutethreshold
Medium
Intensity of stimulus
Percentageof correctdetections
Subliminal stimuli
Weber’s Law- to perceive as different, two stimuli must differ by a constant minimum percentage light intensity- 8%
weight- 2%
tone frequency- 0.3%
*Using one category from above, create a real-world example
Sensory adaptation- diminished sensitivity as a consequence of constant stimulation
1. Hit your forearm. Stop and respond.
2. Continuously hit your forearm for 30 sec.
…Hot peppers?
Ernst Heinrich Weber (1795–1878) was one of the first people to approach the study of the human response to a physical stimulus in a quantitative fashion. His law states that the just-noticeable difference between two stimuli is proportional to the magnitude of the stimuli.
Gustav Theodor Fechner (1801–1887) later offered an elaborate theoretical interpretation of Weber's findings, in which he attempted to describe the relationship between the physical magnitudes of stimuli and the perceived intensity of the stimuli
Transductionconversion of one form of energy to another
in sensation, transforming of stimulus energies into neural impulses
(sensory stimuli > transduction to neural message > brain)
Wavelength
the distance from the peak of one wave to the peak of the next (which distinguish color differences)
Hue
dimension of color determined by wavelength of light
Intensityamount of energy in a wave determined by amplitude
brightness
loudness
Short wavelength=high frequency(bluish colors, high-pitched sounds)
Long wavelength=low frequency(reddish colors, low-pitched sounds)
Great amplitude(bright colors, loud sounds)
Small amplitude(dull colors, soft sounds)
The spectrum of electromagnetic energy
Pupil- adjustable opening in the center of the eye
Iris- a ring of muscle that forms the colored portion of the eye around the pupil and controls the size of the pupil opening
Lens- transparent structure behind pupil that changes shape to focus images on the retina
Retina- the light-sensitive inner surface of the eye, containing receptor rods and cones plus layers of neurons that begin the processing of visual information
Fovea- central point in the retina, around which the eye’s cones cluster
http://youtu.be/cFVbLnXWn6A
Accommodation- the process by which the eyes lens changes shape to help focus near or far objects on the retina
http://youtu.be/hMHKJF31lBg
Acuity- the sharpness of vision
Nearsightedness- condition in which nearby objects are seen more clearly than distant objects because distant objects in front of retina
Farsightedness- condition in which faraway objects are seen more clearly than near objects because the image of near objects is focused behind retina
Rods
peripheral retina
detect black, white and gray
twilight or low light
Cones
near center of retina
fine detail and color vision
daylight or well-lit conditions
http://youtu.be/15P8q35vNHw
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
Optic nerve- nerve that carries neural impulses from the eye to the brain
Blind Spot- point at which the optic nerve leaves the eye, creating a “blind spot” because there are no receptor cells located there
http://youtu.be/aB_oEknhlW8
Feature Detectors
nerve cells in the brain that respond to specific features
shape
angle
movement
Stimulus
Cell’s responses
Parallel Processingsimultaneous processing of several aspects of a problem simultaneously
Trichromatic (three color) TheoryYoung and Helmholtz
three different retinal color receptors
red
green
Blue
http://youtu.be/xzmXrC-Yzfc
People who suffer red-green blindness have trouble perceiving the number within the design
Opponent-Process Theory-
opposing retinal processes enable color vision
“ON” “OFF”red green
green red
blue yellow
yellow blue
black white
white black
Color ConstancyPerceiving familiar objects as having consistent color, even if changing illumination alters the wavelengths reflected by the object
Audition http://youtu.be/PeTriGTENocthe sense of hearing
Frequencythe number of complete wavelengths that pass a point in a given time
Pitcha tone’s highness or lowness
depends on frequency
Short wavelength=high frequency(bluish colors, high-pitched sounds)
Long wavelength=low frequency(reddish colors, low-pitched sounds)
Great amplitude(bright colors, loud sounds)
Small amplitude(dull colors, soft sounds)
Middle Earchamber between eardrum and cochlea containing three tiny
bones (auditory ossicles- the smallest bones in the body) that concentrate the vibrations of the eardrum on the cochlea’s oval window
hammer/malleus anvil/incus stirrup/stapes
Inner Ear innermost part of the ear, contining the cochlea, semicurcular
canals, and vestibular sacsCochlea
coiled, bony, fluid-filled tube in the inner ear through which
http://youtu.be/ahCbGjasm_E
EXPLAIN WHAT IS HAPPENING IN YOUR EAR AS YOU HEAR:
Place Theory
the theory that links the pitch we hear with the place where the cochlea’s membrane is stimulated
Frequency Theory
the theory that the rate of nerve impulses traveling up the auditory nerve matches the frequency of a tone, thus enabling us to sense its pitch
#1 and #4, say something to your partner in two different pitches. Partners- EXPLAIN WHY/HOW WE HEAR DIFFERENCES IN PITCH USING BOTH THEORIES. Which do you agree with and why?
Conduction Hearing Loss
hearing loss caused by damage to the mechanical system that conducts sound waves to the cochleahttp://youtu.be/B6wKNEwYs4M
Nerve (Sensorineural) Hearing Loss
hearing loss caused by damage to the cochlea’s receptor cells or to the auditory nerve
http://youtu.be/YpIptQSEEjY
Older people tend to hear low frequencies well but suffer hearing loss for high frequencies
1time
10times
100times
1000times
32 64 128 256 512 1024 2048 4096 8192 16384
Frequency of tone in waves per second
Low Pitch High
Amplitude required forperception relative to 20-29 year-old group
Skin Sensationspressure
only skin sensation with identifiable receptors
warmth
cold
pain
Gate-Control Theory http://youtu.be/vnChL9VSmeQ
theory that the spinal cord contains a neurological “gate” that blocks pain signals or allows them to pass on to the brain
“gate” opened by the activity of pain signals traveling up small nerve fibers
“gate” closed by activity in larger fibers or by information coming from the brain
Taste Sensations
Sweet=
Sour=
Salty=
Bitter=
Umami=
Sensory Interaction
the principle that one sense may influence another
as when the smell of food influences its taste
Apply to real-life example involving other senses.
Receptor cells inolfactory membrane
Nasal passage
Olfactorybulb
Olfactorynerve
Women
Men
10-19 20-29 30-39 40-49 50-59 60-69 70-79 80-89 90-99Age Group
4
3
2
0
Numberof correct
answers
Women and young adults have best sense of smell
Kinesthesis http://youtu.be/q6-DmvRjc0Q
the system for sensing the position and movement of individual body parts
Vestibular Sense http://youtu.be/q39A9rI2rew
the sense of body movement and position
including the sense of balance