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

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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