Psych Unit 2

Absolute threshold

• smallest amount of any stimulus that can be detected at least 50% of the time

difference threshold

• smallest amount of change between 2 stimuli

• that can be detected at least 50% of the time

• “just noticeable difference”

Weber’s Law

• principle of sensation holding that the size of a just noticeable difference is a constant proportion of the size of an initial stimulus

Transduction

• how we convert a physical stimulus into a neural impulse

Pupil

• allows light to pass through your eye on the way to retina

• opening in the middle of iris

• changes size to let different amounts of light pass through

Iris

• gives your eye the color

cornea

• a protective layer

• 60 - 65% of total focusing power

sensation

• refers to the process of detecting a physical stimulus

• such as light, sound, heat, pressure

Perception

• refers to the process of integrating, organizing, and interpreting sensations

lens

• a transparent structure, located behind the pupil, that actively focuses, or bends light as it enters the eye

Accomadation

• the process by which the lens changes shape to focus the incoming light so that the light falls on the retina

Retina

• a thin, light sensitive membrane located at the back of the eye which contains the sensory receptors for vision

Rods (contained in the retina)

• long, thin, blunt sensory receptors of the eye that are highly sensitive to light, but not to color

• peripheral vision

• night vision

cones

• short, thick, pointed sensory receptors of the eye that detect color

• color vision

• visual activity

Fovea

• small area in the center of the retina

• composed of entirely of cones

• where visual information is most sharply focused

optic nerve

• the thick nerve that exits from the back of the eye

• carries visual information to the visual cortex in the brain

Trichromatic theory

• sensation of color results because cones are especially sensitive to red light, green, or blue

opponent process theory

• that color vision is the product of opposing pairs of color receptors

• when 1 member of a pair is stimulated, the other color is inhibited

outer ear

• collects sound waves

• includes the pinna, the ear canal, and ear drum

Pinna

• help located the location of the sound

ear drum

• tightly stretched membrane that vibrates when hit by sound waves

cochlea

• the coiled, fluid filled inner - ear structure that contains the basilar membrane and hair cells

Inner ear

• sound is transduced into neural impulses

• it consist of the cochlea and semicircular canals

Basilar membrane

• the membrane within the cochlea of the ear that contains the hair cells

hair cells

• the hair like sensory receptors for sound which are embedded in the basilar membrane

Frequency theory

• the view that the basilar membrane vibrates at the same frequency as the sound waves

Place theory

• the view that different frequencies cause the larger vibrations at different locations along the basilar membrane

olfaction

• scientific name for the sense of smell

Gustation

• scientific name for sense of taste

Olfactory bulb

• at the front of the brain

• where the sensation of smell is registered

4 basic skin senses

• pressure

• warmth

• cold

• pain

receptors for touch and body sense are found in

• skin

• mucous membranes

• muscles

• tendons

• joints

Proprioceptors

• respond to motion

mechanoreceptors

• respond to pressure and mechanical

nociceptors

• respond to strong pressure and extreme skin temps

thermoreceptors

• respond to slight/moderate temps

A-delta fibers

• fast pain system

• thalamus to sensory cortex

• sharp, intense, short-live pain of immediate injury

C-fibers

• slow pain system

• hypothalamus and thalamus to limbic system (amygdala)

• longer lasting throbbing, burning pain of injury

Kinesthesis

• system for sensing the position of movement of individual body parts

Vestibular sense def

• sense of body movement and positioning including the sense of balance

Vestibular system

• 3 semicircular canals, fluid and hair cells

• canals arranged at roughly right angels

• hair cells act as mechanoreceptors

vestibular sense

• contributes to spatial orientation

• may cause nausea if vision and vestibular sense are in a conflict

• coordinates muscle movements in eyes

• helps maintain blood supply to the brain

Gate control theory

• physiological and psychological factors cause spinal gates to open and relay to the brain patterns of stimulation that are perceived as pain

Bottom up processing

• emphasizes sensory receptors in detecting the basic features of a stimulus

• attention focuses on the parts of the pattern before moving to the whole

Top-down processing

• emphasizes the observed experience in arriving at meaningful perceptions

• attention moves from the whole part of the pattern

gestalt psychology

• a school of psychology that maintained sensations are actively processed according to consistent perceptual rules producing meaningful whole perceptions or gestalts

• found by German psychologist - MAX WERTHEIMER

figure ground relationship

• gestalt principle stating that a perception is automatically separated into a figure; which is the main element of the scene, and the ground, which is its background

Monocular cues

• distance or depth cues that can be processed by either eye alone

Retina (the image)

• is upside down (inverted) and smaller, walking on the ceiling

Cones =

color, high def

Fovea is the

• point of central focus

• greatest concentration of cones

blind spot

• where the optic nerve exits the back of the eye

• lacks rods and cones

• cant detect light

Main concepts of sound

• frequency (pitch)

• Amplitude (loudness)

• Complexity (timbre)

Volley Theory

• proposes that out brin decodes pitch by noticing the frequency at which groups of hair cells on the basilar membrane are firing

Law of Pragnanz

• refers to our tendency to efficiently organizes the visual elements of a scene in a way that produces the simplest most stable forms or objects

Transduction in hearing

• inner ear; cochlea

• when the hair cells bend, they convert the pressure waves into signals that are sent to the brain by the auditory nerve

Transduction in sight

• retina

• light reflected from surfaces provides the eyes with information about shape, color, and position of objects

transduction in smell

• olfactory bulb

• the olfactory receptors convert the odorants into signals that are transmitted directly to the brain by the olfactory nerves

Transduction in touch

• skin

• the warm, cold, and pressure receptors convert the stimulation into signals that are transmitted to the brain by the various nerves

transduction in taste

• tounge

• the chemical energy is converted by the receptor cells on the taste buds into electrochemical nerve impulses

examples of absolute threshold

• Vision (candle flame seen at 30 miles on a clear night)

• Hearing (tick of a watch under quiet conditions at 20 feet)

• touch (bees wing falling on your cheek from 1cm above)

• smell (1 drop of perfume diffused into a 3-room apartment)

• Taste (1 teaspoon of sugar in 2 galloons of water)

Examples of difference threshold

• the smallest difference in a sound for us to perceive a change in the radios volume

• the minimum difference in weight for us to perceive change between 2 piles of sand

Examples of Weber’s law

• if you have a cup of coffee that has only a very little bit of sugar in it (say 1 tsp), adding another teaspoon of sugar will make a big difference in taste

Signal detection theory

• a theory predicting how and when we detect the presence of a faint stimulus (signal) amid background stimulation (noise). Assumes there is no signal absolute threshold and that detection depends partly on a person’s experience, expectations, motivation, alertness

Sensory adaptation example

• Scent: smokers are not bothered by the smell of tobacco smoke the way nonsmokers are, because smokers are accustomed to the odor

How is vision processed between the eye and the brain

• cornea, pupil, lens, retina, optic nerve, optic chiasm, visual cortex

frequency

• number of sound waves per second

• pitch

amplitude

• wavelengths height

• loudness

External auditory canal

• transmits sound waves from pinna to the tympanic membrane of the middle ear

tympanic membrane

• eardrum

Auditory ossicles

• 3 small bones linked together that connect the eardrum to the inner ear, malleus, incus, stapes

oval window

• membrane that covers the opening between the middle ear and inner ear

Round window

• located just below the oval window

• equalize pressure in the inner ear

Eustachian tube

• a narrow tube between the middle ear and the throat that serves to equalize pressure on both sides of the eardrum

Nasal cavity

• located within and posterior to the nose

cribriform plate

• the horizontal plate of the ethmoid bone separating the cranial cavity from the nasal cavity

How is the chemical compound received in the nose

• airborne molecules travel to the top of nasal cavity and stimulate olfactory receptors

• receptor cells communicate neural messages to olfactory bulb

Orthonasal

• arising from odor compounds traveling through the “external nares” or nostrils, to the olfactory bulb

Anosmia

• inability to smell

papillae

• rough, bumpy elevations on dorsal surface of tounge

What are taste receptors

• clustered deep in the grooves of papillae

what are the specific tastes

• sweet, bitter, sour, salty, unmami

innate preferences for taste

• sweet, salty, Anami

innate dislikes for taste

• sour, bitter

substance p

• a neurotransmitter involved in pain perception

Phantom limb pain

• pain in a limb that no longer exits

Sensitization

• opposite of adaptation

• an increase in behavioral response after exposure to stimulus over time

• example is phantom limb

Figure ground relationships

• the tendency to perceive objects, or figures as existing on a background

binocular cues

• distance or depth cues that require the use of both eyes

induced motion

• the illusory movement of one object that is caused by the movement of another object that is nearby

stroboscopic motion

• the illusion of movement is produced by showing the rapid progression of images or objects that are not moving at all

Muller-lyer illusion

• illusion of line length that is distorted by inward turning or outward turning corners on the ends of the lines, causing lines of equal length to appear to be different

Akinetopsia

• inability to see objects in motion

how does smell connect to the brain?

• smells are handled by the olfactory bulb, it sends info to the other areas of the body’s central command for further processing.

• Odors take a direct route to the limbic system, including the amygdala and the hippocampus, the regions related to emotion and memory

retronasal

• through the mouth, behind the nose

How pressure occurs?

• mechanoreceptors respond to pressure and mechanical stimulus such as a rough or smooth surfaces

• example - blind people reading brail

how hot occurs?

• nociceptors respond to strong pressure in extreme temperatures, as well as responding to pain

How cold occurs?

• thermoreceptors respond to slight/moderate temperatures

how pain occurs?

• body experiences some sort of stimuli that triggers pain

• example - a paper cut or sprained ankles; nociceptors pick up on the stimuli

example of bottom - up perception processing?

• if you see an image of an individual letter on your screen

• your eye transmit the info to your brain

• brain puts all of this info together