General Psychology Test #2 (9,17,18,19,20,21)

sensation

the process by which our sensory receptors and nervous system receive and represent stimulus energies from the environment

perception

the process of organising and interpreting sensory information, enabling us to recognise meaningful objects and events

bottom-up processing

analysis that begins with the sensory 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

our senses…

• receive sensory stimulation, often using specialised receptor cells

• transform that stimulation into neural impulses

  • deliver the neural information to our brain

transduction

the conversion of one form of energy into another

what does psychophysics study?

the relationships between the physical energy we can detect and its effects on our psychological experiences

signal detection theory

predicts how and when we will detect a faint stimulus amid background noise

individual absolute thresholds

vary depending on the strength of the signal and on our experience, expectations, motivation, and alertness

how much of a stimulus does it take to have a sensation? - absolute threshold

minimum stimulation to needed to detect a particular stimulus 50% of the time, e.g. seeing a faraway light in the dark

how much of a stimulus does it take to have a sensation? - subliminal

input below the absolute threshold for conscious awareness

how much of a stimulus does it take to have a sensation? - priming

activating, often unconsciously, associations in our mind, setting us up to perceive, remember, or respond to objects or events in certain ways

how much of a stimulus does it take to have a sensation? - difference threshold

minimum difference a person can detect between any two stimuli half the time; increases with stimulus size

how much of a stimulus does it take to have a sensation? - Weber’s law

for an average person to perceive a difference, two stimuli must differ by a constant minimum percentage (not a constant amount); the exact proportion varies, depending on the stimulus

subliminal stimuli

stimuli that are too weak to detect 50% of the time

subliminal sensation

sensation that is too fleeting to enable exploitation with subliminal messages

subliminal persuasion

may produce a fleeting, subtle, but not powerful enduring effect on behaviour

what does sensory adaptation do?

• diminishes sensitivity as a consequence of constant stimulation

• increases focus by reducing background chatter

• influences how the world is perceived in a personally useful way

  • influences emotiona

perceptual set

a mental predisposition to perceive one thing and not another

what determines our perceptual set?

schemas organise and interpret unfamiliar information through experience. pre-existing schemas influence top-down processing of ambiguous sensation interpretation, including gender stereotypes

context effects of perceptual sets

a given stimulus may trigger different perceptions because of the immediate context

motives in perceptual sets

gives us energy as we work toward a goal and can bias our interpretations of neutral stimuli

emotions in perceptual sets

can move our perceptions in one direction or another

wavelength

distance from the peak of one light or sound wave to the peak of the next

hue

dimension of colour that is determined by the wavelength of light; what we know as the colour names

intensity

amount of energy in a light or sound wave, which influences what we perceive as brightness or loudness and is determined by the wave’s amplitude (height)

retina

the light-sensitive inner surface of the eye, which contains the receptor rods and cones plus layers of neurons that begin the processing of visual information

accomodation

the process by which the eye’s lens changes shape to focus near or far objects on the retina

frequency

the number of complete wavelengths that can pass a point in a given time and depends on the length of the wave

what does the wave amplitude determine?

the brightness of colours, and the loudness of sounds

rods

retinal receptors that detect black, white, and grey and that are sensitive to movement; necessary for peripheral and twilight vision when cones don’t respond

cones

retinal receptors that are concentrated near the centre of the retina and that function in daylight or in well-lit conditions. Cones detect fine detail and give rise to colour sensations

optic nerve

the nerve that carries neural impulses from the eye to the brain

blind spot

the point at which the optic nerve leaves the eye, creating a “blind” spot because no receptor cells are located there

fovea

the central focal point in the retina, around which the eye’s cones cluster

steps to the retina reacting to light

1. light entering eye triggers chemical reactions in rods and cones at the back of the retina

2. chemical reaction in turn activates bipolar cells

3. bipolar cells then activate the ganglion cells, whose combined axons form the optic nerve. This nerve transmits information (via the thalamus) to the brain’s visual cortex

number of cones in one eye

6 million

location of cones in the retina

centre

sensitivity of cones in dim light in the eye

low

colour sensitivity of cones in the eye

high

detail sensitivity of cones in the eye

high

number of rods in one eye

120 million

location of rods in retina

periphery

sensitivity of rods in dim light

high

colour sensitivity of rods in the eye

low

detail sensitivity of rods in the eye

low

how does the brain turn light stimuli into useful information about the world?

• collection and analysis of sensory information

  • linkage of the optic nerve with neurons in the thalamus

two stages of colour processing

1. retina’s red, green, and blue cones respond in varying degrees to different colour stimuli (as suggested by the Young-Helmholtz trichromatic theory)

   1. cones’ responses are then processed by opponent-process cells, as Hering’s theory proposed

feature detection

nerve cells in the brain respond to specific features of the stimulus, such as its shape, angle, or movement

Hubel and Wiesel’s discoveries

• the brain’s computing system deconstructs and then reassembles visual images

  • specialised occipital lobe neuron cells receive information from ganglion cells and pass it to supercell clusters

steps to visual information processing

1. view a scene

2. retinal processing: rods and cones → bipolar cells → ganglion cells

3. feature detection: brain’s detector cells respond to specific features - edges, lines, and angles

4. parallel processing: brain cell beams process combined information about colour, movement, form, and depth

5. recognition: brain interprets the constructed image based on information from stored images

3 principles used to organise sensations into perception by Gestalt psychologists

form perception, depth perception, and perceptual constancy

how do we know where one object begins and another ends? - figure-ground

organisation of the visual field into objects that stand out from their surroundings

how do we know where one object begins and another ends? - grouping

perceptual tendency to organise stimuli into meaningful groups

3 grouping strategies used by the human mind to see patterns and objects

proximity, continuity, closure

depth perception

the ability to see objects in three dimensions, although the images that strike the retina are two-dimensional

allows us to judge distance

is partly present at birth in humans and other animals

the visual cliff

test of early 3D perception - most infants refuse to crawl across the visual cliff and crawling seems to increase an infant’s fear of heights

binocular cues

two eyes improve depth perception

retinal disparity (used by 3D filmmakers)

binocular cues for perceiving depth - the brain calculates distance by comparing images from the two eyes

monocular cue

a depth cue available to either eye alone

examples of monocular cues

light and shadow, relative motion, relative size, linear perspective, interposition, relative height

phi phenomenon

an illusion of movement created when two or more adjacent lights blink on and off in quick succession

perceptual constancy

objects are perceived as unchanging - having colour, brightness, shape, and size - even as illumination and retinal images change

colour constancy

perceiving familiar objects as having consistent colour, even if changing illumination alters the wavelengths reflected by the object

examples of motion perception

when large and small objects move at the same speed, the large objects appear to move more slowly

size constancy

perception of objects as having constant size even when our distance from them varies

perception of the form of familiar objects as constant even when the retina receives changing images

perceptual adaptation

ability to adjust to changed sensory input, including an artificially displaced, or even inverted visual field

restored vision and sensory restriction

effects of sensory restriction on infant cats, monkeys, and humans suggest that there is a critical period for normal sensory and perceptual development. without stimulation, normal connections do not develop

sound waves

go from the environment to into the brain and compresses and expands air molecules

amplitude (height) determines…

the intensity (loudness) of sound waves

length (frequency) determines…

the pitch

what is sound measured in?

decibels (dB)

what are the two types of hearing loss

sensorineural hearing loss (nerve deafness) and conduction hearing loss

sensorineural hearing loss

damage to cell receptors or associated nerves

conduction hearing loss

damage to the mechanical system that conducts sound waves to the cochlea

cochlear implant

a device for converting sounds into electrical signals and stimulating the auditory nerve through electrodes threaded into the cochlea

place theory in hearing

links the pitch heard with the place where the cochlea’s membrane is stimulated; best explains high pitches

frequency (temporal) theory in hearing

theory that the rate at which nerve impulses travel up the auditory nerve matches the frequency of a tone, thus enabling its pitch to be sensed; explains low pitches

combinations of place and frequency theories

handles the pitches in the intermediate range

four distinct skin senses in a sense of touch

pressure, warmth, cold, pain

stages of the pain circuit

1. sensory receptors (nociceptors) respond to potentially damaging stimuli by sending an impulse to the spinal cord

2. the spinal cord passes the message to the brain, which interprets the signal as pain

controlling pain - placebo

reduces central nervous system attention and responses to pain

controlling pain - distraction

draws attention away from painful stimulation

social influence theory in hypnosis

dual-processing state sensory information does not reach areas where pain-related information is processed

dissociation theory in hypnosis

hypnosis is a special dual-processing state of dissociation - a split between different levels of consciousness

taste

involves several basic sensations and can be influenced by learning, expectations, and perceptual bias

sweet taste indicates…

energy source

salty taste indicates…

sodium essential to physiological processes

sour taste indicates…

potentially toxic acid

bitter taste indicates…

potential poisons

umami taste indicates…

proteins to grow and repair tissue

smell

a chemical sense which involves hundreds of different receptors and odors that can evoke strong memories

kinaesthesia

system for sensing the position and movement of individual body parts and interacts with vision

vestibular sense

sense of body movement and position, including the sense of balance

embodied cognition

influence of bodily sensations, gestures, and other states on cognitive preferences and judgments

examples of embodied cognition

physical warmth may promote social warmth

social exclusion can literally feel cold

political expressions may mimic body positions

most relevant ESP claims

telepathy, clairvoyance, precognition, psychokinesis

what is learning?

process of acquiring through experience new information or behaviours

learning through associative learning:

certain events occur together; stimuli that are not controlled are associated, and the response becomes automatic (respondent behaviour)

learning through consequences

association between a response and a consequence is learned