Sensation

- Detecting physical energy from the environment and encoding it as neural signals

Vocab

Sensory Receptors- sensory nerve endings that respond to stimuli

Bottom Up- info processing that starts at sensory receptors then goes to brain, integration of sensory info

Top Down- info processing guided by higher level thinking, constructing perceptions based on experiences or expectations

Transduction- converting one form of energy into another

1. receive sensory stimulation with receptor cells

2. transform stimulation into neural impulses

3. deliver info to brain

Psychophysics- study of relationships between physical energy and effects on psychological experience with them

Threshold Vocab

Absolute Threshold- minimum stimulus energy needed to detect a particular stimulus 50% of the time

Signal Detection Theory- predicts how/when we detect presence of faint signal with background noise, assume no AT, detection depends on experience, expectation, motivation and alertness

Subliminal- stimulus below AT, can effect subconscious mind

Priming- unconscious activation of associations

Difference Threshold- the minimum stimulus difference btwn 2 stimuli required for detection 50% of the time

Webers Law- 2 stimuli must differ by constant minimum PERCENTAGE

Sensory Adaptation

• diminished sensitivity as consequence of constant stimulation bc nerves fire less frequently

• eyes will never adjust bc constantly moving

• changing stimulation puts attention on that

• repetition frees attention to see other things

Vision

color= electromagnetic energy our visual system perceives

wavelength- distance from one peak to other

hue- dimension of color determined by wavelength/freq

intensity- amount of energy wave contains, determines brightness

short wavelength= high freq, blue

long wavelength= low freq; red

big amp= bright

small amp= dull

The Eye

1. light enters through cornea, clear protective outer layer

2. goes to ring of colored muscle tissue iris; dialates/constricts light/cognitive

3. passes through pupil; adjustable opening in center where light enters

4. hits the lens; transparent structure changes shape to help focus on images on retina

5. focuses image on retina; light sensitive back with rods/cones

   • uses accommodation: where eyes lens changes shape to focus images of near/far objects

   • Nearsighted; near objects clear, far blurry

   • Farsighted; far objects clear, near blurry

6. hits rods, retinal receptors that pick up black, gray and white,

   • good for movement, peripheral and twilight, longer, more of them, high sensitivity in dark

7. hits cones, retinal receptors in fovea that pick up color and detail

   • daylight, well lit, less, low sensitivity in dark, color only

8. spark neural signals in optic nerve that carries impulses from eye to brain

   • hits bipolar cells first

   • then hits ganglion cells

   • then optic nerve fully

9. Goes from thalamus, to visual cortex to frontal cortex

Eye has blind spot- where ON leaves the eye and there are no receptors

Fovea- central point in retina, cones cluster, have direct lines to brain

Color Processing

Young Helmholtz trichromatic theory:

• retina has 3 types of color receptors, red, green blue

• use combination of cones to see other colors, with deficiency lack red and/or green

Opponent Processing Theory:

• enables color vision with red/green, yellow/blue, black/white

• see red or green bc can’t travel together down nerve

• retinas conses respond in varying degrees to dif color stimuli

• cones responses processed by opponent processing cells

• explains after images, and negative color

Feature Detecting: nerve cells in visual cortex that respond to specific feature like shape, angle, movement SLAM; located in frontal cortex

Parallel Processing: process multiple aspects of stimulus simultaneously done by comparing stored info

Hearing

Audition- sense of hearing

Sound localization- sounds that reach one ear faster than other allows us to localize

Sound Waves

amp determines loudness

frequency- number of complete wavelengths that pass a point, determines pitch

pitch- tones experienced highness or lowness

short wl: high freq, high pitch

long wl: low freq, low pitch

• sound measured in decibels

The Ear

1. sound waves hit eardrum and cause it to vibrate

2. piston with hammer anvil and stirrup pick vibrations and transmit to cochlea (ossicles)

   • middle ear- chamber between eardrum and cochlea with 3 bones

3. oval window vibrates causing fluid motion in cochlea

   • cochlea- coiled bony fluid filled tube in inner ear, sound waves traveling through fluid trigger nerve impules

   • inner ear- innermost part of ear with cochlea, semicircular canals and vestibular sacs

4. ripples in basilar membrane, bending hair cells

5. adjacent cells on auditory nerve triggered

6. carries message to thalamus

7. then onto auditory cortex in frontal lobe

   

Loss

Sensorineural Loss- damage to cochleas hair cell receptors or to auditory nerve

Conduction loss- damage to mechanical system that conduct sound waves to cochlea, hereditary

cochlear implant- device that converts sounds into electrical signals that stimulates auditory nerve through electrode in cochlea

Pitch Theories

Place Theory- the pitch we hear depends on the place where the cochleas membrane is stimulated, some hairs vibrate with high others with low

Frequency Theory- the pitch we hear depends on the rate of the nerve impulses traveling up auditory nerve, hair cells vibrate at dif speeds

Tactile

pain - bodys way of saying something is wrong

• focuses on pressure, pain, warmth, and cold

Gate Control Theory- the spinal cord contains a neurological gate that blocks pain signals or allows them to pass onto brain, ex may feel pain next day. BLOCKS SUBS. P

Taste

gustation- sense of taste

• uses sweet, salty sour, bitter, umami, oleogustus

• fungiform papilla is where tastebuds are located

• more tastebuds= more sensitive and supertaster

• age increases, receptors decrease

Smell

olfaction- sense of smell

1. smell reaches receptor cells at top of nasal cavity

2. olfactory cells activated and send electrical signals

3. signals relayed via converged axons

   • Bypasses thalamus

• odors trigger combinations of receptors in patterns that are interpreted

• odors depend on associations and can evoke emotions

• must learn dif scents to identify

• hard to recall and describe

• easy to recognize older smells and associated memories

Body Position and movement

Kinesthesis- movement and position of INDIV. parts, without feel disembodied

Vestibular Sense- sense of body movement and position that enables sense of BALANCE

• uses semicircular canals and vestibular sacs in ear, guided by cerebellum

Sensory Interaction

McGurk Effect- seeing one word being said and hearing another can lead to first being heard or combination

Embodied congnition- influence of body sensations gestures and other states on cognitive preferences and judgement

Sensory Interaction- how one sense can influence another

Synesthesia- stimulation of one sense triggers an experience of another; ex- music activates color

Perception

Selective Attention- focusing on one aspect at a time

Cocktail Party Effect- ability to attend to only one voice among many

Inattentional Blindness- failing to see visible objects when attention is focused on other things

• ex gorilla

Change Blindness- failing to notice changes in environment

• ex door exp. where person changes

Perceptual Sets- mental predisposition to perceive one thing and not another based on expectations and experience

Context- effects your perception on environment and surroundings

Gestalt Psychology

-emphasizes our tendency to integrate information into meaningful groups or tendencies

• Figure/Ground- seeing two different images

• proximity- if one set of things are close to another

• similiarity- same attributes

• continuity- line keeps going

• closure- coloring in, finishing line

Depth Perception- ability to see objects in 3D, enables to judge distances

Visual Cliff/Gibson and Walk- once babies are old enough to crawl the have developed depth perception and will not go off cliff

Monocular Cues

-methods used by one eye to judge depth perception

1. relative size- same size, smaller one= farther away

2. interposition- objects that block in front are closer

3. relative clarity- hazy objects are further away

4. texture gradient- indistinct is distance

5. relative height- higher in vision are further away, lower are closer

6. relative motion/parallax- objects closer to fixation point go faster

7. linear perspective- appear to converge into one

8. light and shadow- nearby objects reflect more light- dimmer ones far away

Binocular cues

-methods used by both eyes to judge depth perception

Retinal Disparity- as an object comes closer to us, the differences in images between eyes become greater

Convergence- as an object comes closer our eyes have to come together to keep focused on object

Motion Perception

stroboscopic movement- illusion of continuous movement experienced when viewing rapid series of slightly varying still images

phi phenomenon- illusion of movement created when 2 adjacent lights blink on and off in quick succession

autokinetic effect- illusory movement of still spot of light in dark room

Perceptual Constancy

-perceiving objects as unchanging as illumination or retinal images change

Color Constancy- familiar objects having consistent color even if illum. alters the wavelength reflected

Brightness constancy- perceiving object as having constant brightness as illumination varies

Shape Constancy- perceive form of familiar objects with changing images

Size constancy- unchanging size while distance varies

Perceptual Adaptation- diminished sensitivity as a result of constant stimuli, ability to adjust to changed input