Psych Unit 3

sensation

sensation

bringing in sensory stimuli from the environment (to the brain)

perception

organization and interpretation of sensory info

synesthesia

"cross talk" of the senses

absolute threshold

minimum amount of energy needed to detect the presence of a stimulus. lower threshold = more sensitive

just noticeable difference (jnd)( AKA the difference threshold)

minimum amount of energy needed to detect the change in intensity of a stimulus (or notice the difference between stimuli)

Weber's Law

JND is a fixed porportion (%) of the intensity of stimulis (as the inital increases, the JND will also increase)

Signal detection theory

Theory predicting out ability to detect a stimulis "signal" is present (Accuracy) amid backround "noise" and factors that influence it.

signal detection theory outcomes (Hit, miss, false alarm, correct rejection)

hit- present stimulus, present response miss- present stimulus absent response false alarm-absent stimulus present response correct rejection- absent stimulus absent response

factors that influence detection/response criterion

-"noise"-other neural firing (distractions) -physical ability (sensitivity) -expectations -where attention is directed -willingness/reluctance (response criterion)

Subliminal perception

-processing info without consious awaness -subliminal stimuli = below absolute threshold (not aware)

priming

occurs when exposure to a stimulus (consciously or unconsciously) influences our perception (uncons.)

sensory adaption

decline in sensitivity to stimuli that are presented a constant level (our afferent neurons become less responsive)

transduction (+steps)

converting energy into neural impulses steps:

1. sensory stimuli from env.

2. accessory structure

3. transduction at sensory receptors

4. thalamus (except smell)

5. appropriate part of cerebral cortex.

temporal vs spatial coding

temporal code - changes in neural activity rates or timing

spatial code- physical location of neuron activity

Characteristics of light (how do they translate to psychological characteristics?) 1. amplitude 2. wavelenghts 3. purity

physical characteristics

1. amplitude

2. wavelength

3. purity (#of different wavelengths)

Psychological characteristics

1. Brightness /intensity

2. color / hue

3. saturation (fewer differnt wavelengths = more saturated / pure)

Visual Process (include ALL parts)

1. light wave

2. cornea (outer protective layer)

3. iris (colored muscle that adjusts pupil) + pupil (opening to the eye; lets light in)

4. lens (focuses image on retina; accessory structure for vision).

5. Image is converted onto the retina

6. Retina (back wall of the eye; contains photoreceptors [ rods and cones ] where transduction occurs)

7. photoreceptors (rods and cones ~ sensory receptors for vision) responsible for transduction. 8.bi polar cells (receive visual signals from photo receptors [ rods and cones ] help us to see contrast and edges. )

8. ganglion cells (signals sent from the bipolar cells to the ganglion cells.

9. axons of the ganglion cells bundle together to form the optic nerve.

10. optic disk (Where optic nerve leaves the eye) *blind spot

11. thalamus (All the senses except for smell)

12. occipital lobe (visual cortex)

Accomodation

the ability of the lens to bend light rays in order to focus the image ( based on the object's location) on the retina.

Near sightedness (myopia)

occurs when the lends BENDS TOO MUCH. The image falls in front of the retina

far sightedness (hyperopia)

occurs when the lens does not bend ENOUGH. the image falls behind the retina.

photo receptors

• located in the retina sensory receptors for vision ~ responsible for transduction (Rods and cones are examples)

Cones (type of photo receptors)

Color vision, help us to see in the daytime, brighter light, located on the center of the retina

Fovea

Center of the retina; contains highest concentration of cones; greatest visual acuity (detail)

Rods (type of photo receptors)

black and white; (shades of grey); help us to see in dark/dim light; located on the outer edge of the retina, so they are responsible for peripheral vision.

Bipolar cells

receive visual signals from photo receptors (rods and cones) help us to see contrast and edges

ganglion cells

signals sent from bipolar cells to the ganglion cells. axons of the ganglion cells bundle together to form the optic nerve .

optic disk and optic nerve

the optic nerve leaves the eye at the optics disk

blindspot

where the optic nerve leaves the eye. there are no rods / cones which creates a blindspot

optic chiasm

location where the optic nerve of each eye crosses over to the other hemisphere

Lateral Geniculate nucleus (LGN)

A specific place in the thalamus that processes visual info

Feature detectors

specialized cells that respond selectively to specific features or more complex stimuli (ex: edges, lines, angles, etc)

parallel processing

processing visual info is done simultaneously (as opposed to serial processing)

prosopagnosia

the inability to recognize human faces (Sometimes known as face blindness)

additive color mixing vs subtractive color mixing

Additive Color mixing Light: as you mix light waves together, the color gets lighter. all together = white

Subtractive color mixing: paints: as you mix colors together, the color gets darker. all together = black

young-helmholtz trichromatic theory

there are 3 types of receptors (cones) with differing sensitivities to different wavelengths that can create all colors (red, green, blue)

color blindness + what theory does it support?

lack one of the 3 (or more in rare cases) types of cones. (are able to discriminate fewer colors than other people.)

supports the young Helmholtz theory of color vision

opponent process theory

color perception is determined by the activity of 3 opponent systems; yellow-blue, red-green, and black white.

after images

an image continuing to appear in one's vision after the exposure to the original image has been creating (supports the opponent process theory of color vision)

figure-ground processing

foreground + focus background + unfocused

perceptual set

the tendancy to percieve a stimuli in a particular way guided by prior experiences, expectations, surroundings/context, current mood

intentional blindness and change blindness

failure to see visible objects or events (or change in enviornment)because ones attention is elsewhere. Or we stopped proccessing due to top down processing

bottom-up processing

using details/feautures/characteristics (sensory input) to guide our perception (understand our world)

top-down processing

using prior experiences, expectations, context to guide perception. (understand our world). we make quick assumptions using very little "evidence" (Sensory input)

Gestalt principles-proximity

objects close to eachother are close together

gestalt principles- similiarity

grouping based on like characteristics

visual cliff

the approaches used to test depth perception in infants

Binocular depth cues:

1. retinal (binocular) disparity (difference)

depth perception guided by the different images seen by each eye. (the larger the disparity, the closer the object is perceived to be)

Binocular depth cues: convergence

sensing the eyes converging (turning inwards) as they focus on closer objects

Monocular depth cues: linear perspective

parallel lines "converge" in the distance

Monocular depth cues: texture gradient

more detail = closer

Monocular depth cues: interposition (closer = bigger)

closer objects partially block (overlap) further away

Monocular depth cues: relative size

larger on the retina = closer

Monocular depth cues: height in the plane

near objects = lower in visual field

Monocular depth cues: light and shadow

3D

Monocular depth cues: motion parallax

objects that are closer to us speed across visual field faster than objects further away.

Phi phenomenon / stroboscopic motion

illusion of movement created by presenting visual stimuli in rapid succession

sensation -> perception

looming

as image expands on our retina, we percieve the object as approaching us.

perceptual constancies (size, shape, brightness)

tendency to experience a stable perception despite changing sensory inputs.

characteristics of sound ( how do they translate to psyhcological characteristics?) 1.amplitude 2. wavelength 3. purity

1. loudness /intensity/volume(decibels)

2. pitch (hertz) 3.timbre (unique quality of sound)

Sensory processing in the ear (include ALL parts)

1. soundwave

2. pinna (outer ear) ~ accessory structure for audition

3. ear canal

4. tympanic membrane (eardrum ~ vibrations occur)

5. 3 little bones (malleus-hammer, incus-anvil, stapes-stirrup)

6. oval window

7. cochlea * where transduction occurs)

8. basilar membrane lined with cilia hairs * ~ responsible for transduction (sensory receptors for transduction)

9. auditory nerve

10. thalamus

11. temporal lobe (auditory cortex)

place theory

perception of pitch corresponds to the vibration of different portions, or locations/places along the basliar membrane (spatial code)

best explaines high frequency sounds. (spatial code)

frequency theory

perception of pitch corresponds to the firing rate or frequency at which basilar membranes vibrates. (or firing rate of the neurons or the auditory nerve)

best explains low frequency sounds (temporal code)

conduction deafness

problems/damage to the three little bones or tympanic membrane. ( may be corrected with hearing aids)

sensorineural deafness

problems/damage to the cilia (hair cells) or auditory nerve (may be corrected with a cochlear implant or auditory nerve implant). ~ too much exposure to loud songs

gustation ( is the sense of.... )

taste

olfaction

sense of smell, cilia (hair cells) in the nose

taste buds (papillae)

• other factors that influence flavor

papillae/taste buds contain sensory receptors for taste and there are four tastes; sweet, sour, bitter, salty.

• taste buds are the most sensitive to 1 or 2 tastes and weak to others

flavor is a combination of what 2 senses??

taste and smell

olfactory bulb

cilia in the nose send signals to the olfactory bulb in the brain *does not go through thalamus first (part of limbic system)

vomeronasal organ

part of the nose that detects pheromones

pheromones

chemicals that shape the behavior / physiology of animals.

somatosensory system (touch)

what are the 3 types of touch receptors?

pressure, pain, temperature

A-delta fibers (fast pathway) v.s C-fibers (slow pathway)

a delta fibers - carry quick , localized, sharp pain signals

c fibers- carry chronic (longer lasting),dull,less localized, aches and burning pain signals

gate control theory

pain can be blocked at the spinal cord. other sensory info aside from signals can take over the pain pathway.

analgesia

inability to feel pain (when pain should be present)

vestibular sense

sensory system providing info about spacial orientation (position of head/body in space) as well as our sense of balance.

kinesthesia

coordination

sensory system providing info about where parts of your body are in relationship to each other providing use with our sense of coordination. (ability to sense the movement of muscles, tendons, and joints)