psychology: sensation and perception

the senses

sight- a candle flame can be seen 30 miles away on a dark, clear night

hearing- the ticking of a watch can be heard 20 ft away under quiet conditions

taste- sugar can be discerned when 1 teaspoon is dissolved in 2 gallons of water

smell- perfume can be detected when one drop is present in a three-room apartment

touch - a bee’s wing falling from a distance of 1cm can be felt on the check

what is adaptation?

the sensory capacity following prolonged exposure to stimuli

perception facts idk

• perception physically constructs and colours our world

• in the division of labour, each part of the brain does a little part to help complete the “picture”

• the sense of touch first goes to a thin strip of the cortex, which provides a detailed map of the brain

• physical vibrations are the first step in the production of sound

• smell is the oldest and first sense to develop

• basic quality: salty sour, bitter, sweet and umami “pleasant savoury taste”

Gestalts laws of perceptual organization

1. law of closure

2. law of similarity

3. law of proximity

4. law of simplicity

5. law of continuity

law of closure

• objects grouped together are seen as a whole

• we tend to ignore gaps and complete contour lines

← There are no triangles or circles, but our minds fill in the mission info to create familiar shapes and images

law of similarity

• items that are similar tend to be grouped together

← most people see vertical columns of circles and squares

law of proximity

• Objects near each other tend to be grouped together

← vertical columns and horizontal rows of circles

law of simplicity

we organize it into the simplest form possible

← we see a series of circles rather than a bunch of complicated shapes

law of continuity

• lines are seen as following the smoothest path

← the top branch is seen as continuing the first segment of the line. This allows us to see things as flowing smoothly without breaking lines up into multiple parts

what is sensation

it’s what occurs when a stimulus activates a receptor

what are stimulus

any aspect or change in the environment to which an organism responds

what is perception

the organization of sensory information into meaningful experiences

a sensation may be combined with other sensations and your past experiences to form a perception

absolute threshold

the weakest amount of sensory information that a person can detect half the time

for vision: is the ability to see a candle flame 30 miles away on a clear night

Just noticeable different (JND)

the smallest increase or decrease in the intensity of a stimulus that a person is able to detect half the time

retina

the layer of light-sensitive receptor cells lining the inner eyeball

• at the back of the eye

• detects images focused on the back of the eye by the lens and the cornea

• connected to the brain by the optic nerve

blood vessels

tiny arteries and veins that carry blood to the retina

optic nerve

bundle of nerve fibers that carry information from the retina to the brain

fovea

a dimple in the retina where cones are concentrated and vision is most acute

cornea

a clear tough covering over the iris and the pupil that helps protect the eye and begins focusing light

pupil

an opening that can be enlarged or reduced to let more or less light in by contractions in the muscles of the iris

lens

a clear flexible structure that adjusts the eye’s focus allowing us to see objects both near and far

iris

a muscle that controls the amount of light that enters the eye

• it is suspended between the cornea and the lens

• the colored part of the eye

aqueous humor

a clear fluid that helps the cornea keep it’s shape

vitreous humor

a thick, clear jelly that helps give the eyeball it’s shape

light

needed to entrance vision

how does the eye work

1. light first passes through the cornea

2. light then goes through the pupil

3. light passes through the pupil to the lens

4. light is focused through the lens onto the inner lining of the back of the eyeball, the retina

5. the light stimulates receptor cells called rods and cones

6. chemical processes in these cells lead to firing of sensory neurons

7. the neurons converge to form the optic nerve, which relays the message to the brain

texture gradient

refers to the way the detail of a surface changes with distance

linear perspective

a visual cue in which two parallel lines appear to meet together in the distance

relative size

the perceptual phenomenon where an object's apparent size influences how far away it seems

context effects

how environmental factors can influence a person's perception, judgment, or decision-making

relative height

a concept used in visual and artistic perspective where distant objects are seen or portrayed as being smaller and higher in relation to items that are closer

illusions of length

where two lines of equal length appear different in length, often due to the presence of arrowheads or fins at their ends

zöllner illusion

a perceptual distortion where parallel lines appear to diverge or converge when intersected by short, oblique lines

psychophysics

understanding the relationship between sensory experiences and the stimuli that cause these experiences

difference threshold

the smallest change in a physical stimulus such as light or sound that can be detected half the time

signal-detection theory

based on the notion that the stimulus must be detected in the presence of competing stimuli

explains how you hear your name spoken from across a crowded, noisy room

weber’s law

the stronger a stimulus is, the greater the change must be for a person to notice it

our sense detect relative changes, not absolute ones

ex. in hearing, you’re more likely to notice a volume change of 10% higher in a quiet environment but not as noticeably in a loud environment

what is a receptor

a sensation that occurs any time a stimulus activated

what happens without sensory adaptation

you would feel the constant pressure of the clothes on your body

detection threshold

recognizing some stimulus against a background of competing stimuli

vestibular

the system adjacent to the inner ear that controls balance

auditory nerve

the nerve that sends signals from the inner ear to the brain

olfactory nerve

the nerve that carries signals from the nose to the brain

kinesthesis

the sense of movement and body position

binocular fusion

the combination of two images into one

retinal disparity

the difference between the images stimulating each eye

important to your sense of sight since it’s essential for death perception

how do sensory receptors make it possible for you to perceive external stimuli?

they detect specific types of stimuli (ex. light, sound etc) and send signals through nerves to the brain, where the information is processed

rods

black and white

detect light and dark and are more sensitive in low light

cones

detect color

work best in bright light

why do some people see the world in only blacks, whites, and shades of gray?

colorblindness

due to lack of or non-functioning cone cells in their retina

why would you perceive one object as closer than other?

retina disparity

your brain uses cues such as the size of the image on the retina and how both eyes view the object to determine depth and distance

how would you describe the sound of a bass guitar at a rock concert in terms of sound waves?

it produces low-frequency, high amplitude sound waves that create deep, strong vibrations

how can your ears tell you from which direction a sound is coming?

your brain compares the time it takes of the sound to reach each ear and the intensity difference to determine the direction

if you experience dizziness while riding a roller coaster, what is likely occurring?

vestibular sense is gone

your inner ear fluid is being disturbed, which affects your balance and spatial orientation

why does food often taste bland when you have a cold?

sense of smell is reduced, which greatly affects the perception of flavor

how does feeling pain benefit you

alerts you to potential or actual injury, helping you avoid harm and take care of your body

what process makes it possible to bounce a basketball without looking at it?

kinesthesis

the sense that provides information about the body's position and movement, enabling coordinated actions

subliminal message

a brief auditory or visual signal that occurs below the absolute threshold for that sense

gestalt

the perception principle that assumes that the whole is greater than the sum

extrasensory perception

perceiving information about the world through means other than the sense

constancy

perceiving objects in the same way regardless of their distance, angle, or lighting

motion parallax cue

when you move your head from side to side or walk around, the apparent movement of stationary objects relative to one another

illusions

misrepresentations of physical stimuli

gestalts principles

figure-ground, similarity, proximity, continuity, and closure

ex. closure: when you see a broken circle, your brain fills in the gaps and you perceive a complete circle

what occurs during the perception process?

the brain receives information from the senses and organizes and interprets it into meaningful experiences unconsciously

what is figure-ground perception?

the ability to discriminate properly between a figure and its background

what makes perceptual inference possible

our past experiences that make us know what to expect in the present

some might be born with it

what factors influence learning to perceive?

needs

beliefs

expectations

what are some monocular cues used to perceive distance and depth?

size- the bigger the nearer

height - the object farther away from another are higher on your plane of view

what process produces size constancy?

the brain using depth cues to perceive an objects size as constant, despite is changing in retinal image size due to distance

how are illusions created?

when perceptual cues are dissorted so our brains cannot correctly interpret space, size, and depth cues

what are the 4 types of ESP

telepathy - mind to mind communication

clairvoyance - the power to see things that cannot be perceived by the senses

precognition - ability to foretell events

psychokinesis - ability to move objects with one's mind