Consciousness, Sensation, and Perception

consciousness

• awareness of yourself & your environment

• encompasses thoughts, feelings, & perceptions, allowing for subjective experiences

  • RAS filters out diff stuff for diff ppl

altered state of consciousness

your focus is split, or your quality of cognition declines

preconscious

• smth I’m not currently aware of, but could be if I wanted to

  • ex. walking into biopsych test, not specifically thinking abt medulla, but if I get Q on respiration, then ik medulla

nonconscious

automatic ns (things we do w/o thinking)

subconscious

I’m not fully aware of my motives, but those feelings still influence my behaviors

unconscious

• inaccessible to us

• no way to prove/disprove this; the one stage of consciousness that not everyone agrees w/

biological rhythm

• physiological functions

  • ex. mensuration, puberty

  • can’t be adjusted

circadian rhythm

• 24-hr cycle

  • ex. sleep

  • can be adjusted (in 14 days)

why do we sleep?

• health of body

  • restores us, ex. immune system, cellular damage, etc

• replenishes chemicals used throughout day

• integrates today’s experiences into memory

  • throws out unnecessary memories

• helps us deal w/ stress, anxiety, & emotions

• regulates eating

  • less sleep = obesity

stream of consciousness waves (from most active to least active)

• gamma

• beta

• alpha

• theta

• delta

hypnogogic sensation

• when you feel like you’re falling so body jerks

• happens during NREM 1

how long is sleep cycle?

• 90 mins

• should be going thru cycle 5 times every night

order of sleep cycle

• NREM1 → NREM2 → NREM3 → NREM2 → NREM1 → REM = one 90 min sleep cycle

• cycle begins more heavily in NREM, but as you cont., more time spent in REM

NREM1

• lightest stage of sleep

• starting to emit theta waves

NREM2

• sleep spindles occur

• respiration slows down a little more

• sleep talking/walking occurs

NREM3

• slow wave/restorative sleep

• deep sleep

• taking out trash in brain

• deciding which memories to keep/discard

REM

• rapid eye mvmt

• indicates you’re dreaming

• body enters sleep paralysis, but brain is highly active, esp in cortex

  • “paradoxical sleep”

• respiration rates inc

REM rebound

• inc amt of time spent in REM if I’m habitually depriving it of its normal amt

activation synthesis

• dream theory from biological POV

• synthesizing active neurons

• dreams = brain trying to make sense of random neural activity

information processing

• dream theory from biological & psychological POV

• dreams help you get info into memory system & process emotions of day

Freud’s dream theory

• 1st person who says dreams can mean smth

• dreams = “royal road to unconscious”

• manifest (storyline you can account for) v.s. latent (hidden symbols, interpreted version of dreams) content

somnambulism

• genetic

• sleep walking disorder

• affects NREM sleep

• more common in men than women

• starts in childhood, sometimes fixes itself w/ puberty

sleep apnea

• as you’re laying down, throat closes → stop breathing → brain forces you to rise out of deep sleep to snort up air

narcolepsy

• bout of uncontrollable sleep (short amt of time)

• cataplexy = sudden loss of muscle tone so body goes limp

• almost immediately fall into REM

• treatment = scheduled naps

• genetic

night terrors

• affects NREM sleep

• indiv looks disturbed; can get up, clench teeth, make noises, etc

• more common in boys than girls

• starts in childhood, sometimes fixes itself w/ puberty

insomnia

• most common sleep disorder

• two types:

  • problem falling sleep (more common)

  • problem staying asleep

stimulants

• stimulates ns (CNS & sympathetic NS)

• dilates pupils, inc HR, etc

• ex. cocaine, nicotine, caffeine

• can cause paranoia & insomnia

depressants

• reduce/slow neural activity & body functions

• ex. alc (most common)

hallucinogens

• distort perception & evoke sensory images w/o actual sensory input

• ex. LSD, shrooms

• No. 1 hallucination = seeing smth

  • but for schizo, it’s hearing smth

opiates

• NS slowed AND indiv feels sense of pleasure

  • ex. opium, morphine, heroin

psychoactive drugs

chemicals that change perceptions & moods

agonist

substance that initiatives physiological response when combined w/ receptor

tolerance

diminished response to drug

antagonist

drug that blocks certain neurotransmitter from activating its receptors

withdrawal

symptoms that occur when indiv ends use of addictive substance

sensation

• detecting smth from environment

• biological process = same for everybody

perception

• subjective to everyone

• diff due to…

  • prev experiences

  • what you’re paying attention to/interpreting

transduction

us converting sensed energy into neural impulse

bottom-up processing

going from senses to brain

top-down processing

• from brain to senses

• when brain is trying to interpret smth in absence of stimuli

  • e.g. trying to recall someone’s voice when they’re not there

absolute threshold

• smallest amt of stimuli you can detect reliably (50% of the time)

• declines over time

sensory adaptation

• occurs when you have constant unchanging stimuli, so you get used to it

• happening at 2 diff lvls

  1. sensory neurons fire less frequently

  2. habituation

signal detection theory

• psychological theory

• trying to make sense of why absolute threshold isn’t constant (why only 50% reliable?)

• reason = psychological state isn’t constant; can’t give full attention to everything @ same time

difference threshold/just noticeable difference (JND)

smallest amt of change in ongoing stimuli that you can detect reliably (50%)

selective attention

• pay attention to some info, & exclude irrelevant stuff

• diff types

  1. change blindness

  2. inattentional blindness

  3. cocktail party phenomenon

change blindness

when we fail to notice change in visual stimuli bc attention focused elsewhere

inattentional blindness

when we fail to notice smth that’s fully visible b/c brain is focused elsewhere

cocktail party phenomenon

• when you weren’t paying attention to someone’s convo until they say your name

JND & Weber’s Law

• size of JND = proportional to strength of OG stimuli

  • e.g. changing temp of jacuzzi > changing temp og lukewarm water

  • if you start w/ smth strong → takes more change to notice diff

  • if you start w/ smth not as strong → takes less change to notice diff

can we sense smth below our absolute threshold?

yes, subliminally (below your threshold)

characteristics of waves

1. wave length

2. amplitude

3. complexity

vision & waves

• stimulus = electromagnetic energy

• wavelengths determine hue we see

• amplitude determines how bright hue is

• complexity = range of wavelengths, how saturated color is

sound & waves

• stimulus = pressure waves (created when smth vibrates)

• frequency = rate of vibration

  • high freq = small wavelength

  • freq = pitch of sound

  • measure pitch in Hertz

  • humans can only hear 20-20k Hertz

• amplitude = amt of pressure of waves

  • high amp → high pressure → high volume (loud)

  • measured in decibels

• tambre = tone saturation (combo of diff sounds)

dark adaptation

• happens when we go from light environment to dark

light adaptation

• happens when we go from dark environment to light

  • takes shorter time than dark adaptation

lens

• responsible for inverting the world

• can change its shape thru accommodation

pupil

opening to eye

iris

• adjusts size of pupil

cornea

• protective outer layer

• curvature helps focus light rays inward towards eye so we can see things clearly

blind spot

• black dot in vision that brain fills in for you

fovea

• where we see greatest detail b/c highest density of cones

retina

• where transduction takes place

• covered w/ neurons known as photoreceptors

  • 2 types

    1. rods → black, white, grey

    2. cones → color vision

trichromatic (Young/Helmholtz) theory

• eye has 3-color sensitive cones: R, G, B

• activating them in diff ways results in seeing other colors

color blindness

• sex-linked/x-linked trait → more common in men

• deficiency in cones

  1. red-green

  2. yellow-blue

  3. black-white (rare)

opponent process theory

• when one color is excited, the other is inhibited

  • ex. if I stare at smth blue, yellow is inhibited, & vice versa

• pairs:

  • black white

  • red green

  • yellow blue

pina

funnels sound into ear

inner ear

• where transduction takes place (in cochlear on vascular membrane)

• includes cochlear & semicircular canals

cochlear

responsible for audition & transduction

semicircular canals

responsible for balance

middle ear

• job = conduct vibrations

• includes ear drum & 3 tiny bones (stapes, incus, malleus)

outer ear

• pina & ear canal

conduction hearing loss

• middle ear porblem, 2 possible scenarios

  1. smth happens to eardrum (e.g. tear)

  2. more rare; bones in mid ear start to degenerate → can’t conduct vibrations

sensory neural hearing loss

1. hair cells die

2. auditory nerve doesn’t work

place theory

brain perceives pitch based on where hair cells are moving

frequency theory

brain perceives pitch based on how often auditory nerve is firing

volley principle

grps of hair cells take turns sending action potentials

sensory interaction

experience of one sense influences experience of another sense (ex. smell & taste)

gustation (taste)

• sense receptors = taste buds

• universal love for sweet & distaste for bitter

• bitter = back of tongue by throat

• sour = side of tongue

• salty = front of tongue

• umami = whole tongue

• sweet = front of tongue

olfaction (smell)

• sense receptors = hair cells @ top of nasal cavities

• only sense that bypasses thalamus & goes to olfactory bulb

how are gustation and olfaction similar?

• both sense chemical molecules

• only sense where sensor cells die & are regenerated

• need smell for full taste experience

vestibular sense

• sense of balance

• transduction happens in canals

• canals like cochlear filled w/ liquid + hair cells

• reliant on info your brain gets abt body position & ground

  • ex. where head is compared to ground/how head is moving

    • ex. tilt head, hair cells move

kinesthesis

• provides info to brain abt what body parts are doing

• receptors in muscles, joints, etc in body

  • this is where transduction occurs

  • will send info to brain

• also helps w/ posture

touch

• stimulus = what experience we’re having

  • no one particular

• diff layers of skin respond diff to sensations

• pain is body’s way of letting us know smth is wrong

  1. somatic pain = muscle/tendons in body; quick/sharp pain

  2. visceral pain = internal organs; more consistent (constant ache)

gate control theory

• can’t prove it

• “gate” in spinal cord that can be opened allowing msgs to go up to bran/remain closed and msg doesn’t go up

• “disease”/amputation makes door remain open, causing msg to go up

• mirrors used to treat phantom limb

  • see that it’s fine, gates will close

monocular cues

• there are way more of these than binocular cues

• illusions of depth

interposition

• when one object partially blocks view of another, the one that’s blocked is perceived as being further away

figure-ground relationship

figure is separate from bckgrd

relative size

• assuming two objs are abt same size, the one that casts the smaller retinal image is perceived as being further away

proximity (Gestalt grouping principle)

b/c things are close to one another, they’re percieved as unit/having a relationship

retinal clarity/atmospheric perspective

hazy/blurry objects are perceived as being further away from us

similarity (Gestalt grouping principle

we grp things tg that are similar

common fate (Gestalt grouping principle)

when ppl/animals travelling in same direction, we percieve them as grp

closure (Gestalt grouping principle)

we see things as complete objects, even when they aren’t; filling in gaps, seeing things the way we think they should be even if it’s not actually like that

continuity

we see uninterrupted patterns over smth broken up

law of pragnanz

when brain sees ambiguous visual stimuli, we see it in simplest way possible

texture gradient

objects closer to us, we can see in greater detail + we can also see the spacing in btwn the objects

depth perception isn’t developed until…

the time we learn to crawl

binocular cues

• helps w/ depth perception

  1. retinal disparity: brain perceives depth thru 2 diff images it receives (one from left eye, one from right eye); the greater the disparity, the closer the object

  2. convergence: kinesthesis for your eyes; part of how brain judges depth is based on mvmt of eye muscles more inward; the more eye converges, the closer the object

light & shadow

nearby objects are going to be brighter

linear perspective

when parallel lines are converging, appears more in depth