Sensation and Perception

  • sensation: stimulation of a sensory organ

    • eyes — seeing light

    • nose — smelling an odor

  • perception: identifying and/or interpreting sensation in the brain

    • mental representation

  • transduction: physical signals —neural signals


Detecting Sensations

  • absolute threshold:

    • minimal intensity of stimulus necessary to detect it 50% of the time

      • hearing tests - volume and pitch

      • amount of sugar

  • just noticeable difference:

    • minimal change in a stimulus necessary to detect a change has occured

Signal Detection Theory

  • not everyone detects a stimulus equally

  • signal detection theory:

    • a persons response to a stimulus depends on…

      • sensitivity to stimulus

      • decision criteria

        • do they choose to ignore it? why? - adaptive process

Seeing - Sensing Light

  • length of a wave — color/hue

  • amplitude of a wave — intensity

  • light — pupil

  • pupil — retina

    • cones: color, fine detail, best in daylight

    • rods: best in low light, periphery

  • fovea: no rods, only cones

    • clearest vision

  • retina — optic nerve

    • blind spot

  • optic nerve — area V1 (primary visual cortex)

    • brain then perceives visual info

    • flips image, combines info from both eyes

  • 12% of women are tetra-chromatic

Perceiving Light - Color

  • Color: perceiving lights wavelength

    • 3 types of cones: red, green, blue (combinations)

  • Color deficiency: one or more cones is missing (or fatigued)

    • Color blindness

  • Color-opponent system

    • Pairs of visual neurons work in opposition

    • Green — red

    • Yellow — blue

  • Fatigued cones can’t compete with their opponent

Perceiving Light - Recognizing Objects

  • perceptual constancy: recognizing objects across different contexts

    • small changes

  • Perceptual Organization: brain groups visual info in order to represent a unified object

Perceiving Light - Depth and Size

  • Depth cues: help determine shape and distance of objects

    • monocular or binocular

  • Linear perspective: lines coverage at the furthest point

  • texture gradient: textures further back are harder to see

  • interposition: objects further back are blocked

  • relative height: objects near the top = further

  • binocular disparity: our eyes see from slightly different positions

    • difference in what they see — position/depth of object

Percieving Light - Change

  • change in blindness: failure to detect a change in the visual

    • focused attention


Hearing - Sensing Sound

  • length of wave — pitch (high vs. low)

  • height of wave — loudness

  • ears work together to locate sound

  • cochlea — auditory nerve

  • auditory nerve — area A1 (primary auditory cortex)


  • sound — enter through inner ear

  • ear drum makes vibrations

  • cochlea picks up corresponding vibrations


Hearing Lost

  • conductive hearing loss:

    • due to damage, blockage, or impacted wax

    • sounds can’t make it through the outer/middle ear

  • sensorineural hearing loss:

    • inner ear damage (cochlea) or auditory nerve damage

    • age, noise damage, or tumors

Perceiving Sound

  • McGurk Effect:

    • visual information impacts how auditory information is perceived

    • lip shape

    • facial expressions

Sensing Touch

  • somatosensory receptors within our:

    • skin

    • joints

    • muscles

  • somatory sensory cortex

  • more somatosensory cortex devoted = more fine detail

    • fingertips

    • lips/tongue

Perceiving Pain

  • referred pain: internal pain is felt at the surface of the skin

  • organ damage

  • gate control theory: signals from pain receptors can be stopped (gated) or increased

    • endorphins

    • drugs

    • infection

  • congenital insensensitivity to pain: one cannot perceive pain

    • gene mutation from birth

    • cannot turn pain signals into neutral signals (failure of transduction)

    • extremely dangerous

Sensing Smell

  • mucous membrane in nostrils — olfactory bulb

    • only sense to bypass the thalamus

  • preferences differ

  • smell can help us identify danger

  • strong link to memory

    • proximity to hippocampus

  • we can detect differences in peoples smell

    • children sexual orientation

Sensing Taste

  • taste buds — gustatory cortex (frontal lobe)

  • taste is dependent on smell

    • can detect toxins or expired food

  • cultural differences

  • wine test

    • people prefer wine they think is more expensive

    • cognitive influences

Consciousness

  • subjective expeirence of the world and our mind

    • it is personal to each person

  • problem of other minds: difficulty perceiving the consciousness of others

    • ex: human minds vs cat minds

Properties of Consciousness

  • INTENTIONALITY

    • directed at something

  • UNITY

    • combines info from all senses simultaneously

    • makes sense of multiple inputs

  • SELECTIVITY

    • can focus on a small part of the enviorment

    • filter out extraneous stimuli

    • cocktail party phenomonon

  • TRANSIENCE

    • tendency to shift, or change

    • “stream of consciousness”: cahnge in our attentional focus

Levels of Consciousness

  • Minimal Consciousness:

    • response to senses

    • lack of recollection

    • example: sleeping

  • Full Consciousness:

    • able to report mental state and expeirence

    • recall

  • Self-Consciousness;

    • attentional awareness on the self

    • inward focus

    • embarrassment, shame

    • self evaluation

  • Rouge Test:

    • self recognition in a mirror

    • children, elephants, apes, dolphins

    • to past the rouge test the animal or child needs to reach for their own forehead for self-recognition

Mind Wandering

  • mind wandering: off-task internal thoughts

    • day dreaming

    • planning for the future

  • mental control: controlling our thoughts can be difficult

  • rumination: obsessive thoughts that can impede normal daily function

    • mental control:

      • attempt the change content of thoughts

      • anxious worries — pleasant thoughts

    • thFought supression:

      • tempt to STOP a thought

White Bear Experiment

  • bound effect of thought supression (Wegner)

  • GROUP 1: no instructions (if you happen to think of a white bear ring the bell)

  • GROUP 2: DONT think of a white bear and if you happen to ring this bell

  • GROUP 2: thought of the white bear even more during later thinking period

The Unconscious Mind

  • something in our unconsious is outside of our awareness

  • Freud’s Take:

    • dynamic unconscious - active system below our awareness

    • Ex: maybe there is a reason I picked strawberries today (maybe I smelled strawberres earlier and it fueled me to pick strawberries later)

  • combination of…

    • hidden memories

    • acknowledged desires

  • repression: mental process that keeps undesirable thoughts/memories in the unconscious

    • peaceful, evolved society

  • Freudian slips: error in speech

    • suggests underlying unconscious thoughts/desires

    • mistakes that mean something

A Modern Take

  • cognitive unconscious:

    • underlying processes behind thoughts/feelings/behavior

    • below our awareness

    • save effort

  • duel process theory:

    • two cognitive systems in our brain

    • automatic: quick and effortless

      • 2 + 2

    • controlled: slow and effortful

      • intricate formulas and to solve problems in life

Subliminal Perception

  • influenced by stimuli we can’t report perceiving

Mind-Altering Substances

  • psychoactive drugs decision-making:

    • change consciousness by altering brains NT

Alcohol

  • effects on consciousness:

    • euphoria

    • reduced motor control

    • poor decision making

  • increased GABA (inhibitor)

    • hyperactive nervous system

Marijuana

  • effects on consciousness:

    • poor decision-making

    • reduced motor control

    • increased appetite

    • intensified sensations and altered perception

    • euphoria OR panic

  • related to anandamide (mood, memory, pain, appetite)

Hallucinogens

  • effects on consciousness:

    • intensified sensation and altered perception

    • hallucinations (perceiving things that aren’t there)

    • euphoria OR panic

    • increased brain activity/communication overall

Sleep and Dreaming

  • sleep = mind consciousness

  • Altered state of consciousness:

    • different from average state of consciousness

Stages of Sleep

  • 5 stages of sleep:

    • stage 1 - 4: different brain waves

    • REM sleep:

      • rapid eye movement

      • increased brain activity

      • memory of dreaming

    • All people dream!

Disordered Sleep

  • insomnia: trouble falling and/or staying asleep

    • 30 - 48% of people

    • depression and anxiety

    • worrying about the future

  • somnambulism:

    • sleep walking

    • most frequent between ages 4-7

    • depictions are inaccurate

  • sleep paralysis: awake, but unable to move body

    • dream-like hallucinations

    • Are you fully awake?

  • night terrors: abruptly wakes up from their sleep cycle in panic

    • shouting, sweating, in panic

    • most common in children

    • symptom of PTSD

    • no dream content

Characteristics of Dreams

  • intense emotion

  • vivid visual/auditory sensation

  • illogical and bizarre

    • accepted without question

  • difficult to remember over time

Lucid Dreams

  • Lucid dreaming:

    • awareness that the dream is not real

    • On Dreams by Aristotle

    • dream manipulation

Why Do We Dream

  • Freud’s theory:

    • dreams come from our unconscious

    • manifest meaning: apparent meaning (superficial)

    • latent meaning: true, underlying meaning (ex: desire to eat less meat)

Was Freud Wrong?

  • not entirely

  • suppressed thoughts may rebound in dreams

Why do we Dream?

  • activation-synthesis model:

    • during sleep, neurons fire erratically

    • mind makes sense of random firing — dreams

  • memory and planning:

    • refreshing on daily events

    • planning for the future

Are We Rational Creatures?

  • rational choice theory (economics):

    • likelihood of outcome X value of outcome

    • rational decisions = careful, complex computations

  • psych research suggests otherwise!

Irrational Decision Making

  • judging frequency/probability is imperfect

  • framing effect: people respond differently based on how the problem/statement is framed

  • availability bias: more readily available in memory — judged as occurring more frequently

    • more recently

    • more exciting/frightening

    • more sensation-rationalized

  • Sunk-cost fallacy: decisions based on what has been previously invested

  • Optimism bias: good things are more likely to happen to me!

  • Things will work out!

    • School, work relationships, natural disasters

    • ex: north america vs. Japan

  • Heuristic: fast/quick strategy for the decision-making process

  • Representativeness heuristic: making a judgment by comparing to a prototype of the object/subject

  • Prototype: typical member of a category

    • represents the strategy of the members

Ways to Problem Solve

  • means-end analysis: determining the steps necessary to reach a goal

    • find the “means” to reach the “end”

  • analogical problem solving: find a similar problem with a known solution

    • apply that solution to your own problem

  • creativity: outside-the-box thinking

    • novel (new) and useful solutions

  • Duncker’s candle problem: fix the candle to the wall in a way that the wax won’t land on the table

    • solution: use the box that the candle came in and the box will catch the wax

  • functional fixedness: perceiving an object’s function as unchanging

    • getting “stuck” on one function - failure to think of other functions

    • tack box - hold hacks (not just a candle!)

Remote Associates Task

  • 3 words: man, glue, star

  • the word in front would be “super”

What is Memory?

  • the capability to store/retrieve information over time

  • can be flawed

  • memories are not like perfect video recordings

  • combination of new/old info

    • abstract not concrete

Encoding

  • sensation/perception — lasting construct in the mind

Types of Encoding:

  • sematic coding:

    • meaning of a word, object, event, concept

      • example: is the concept of what the word “cat” means

        • Basically just learning what the visual is and what a cat looks like

  • visual coding:

    • mental picture of word, object, event, concept

      • example: mental image of what your mom’s cat look like

  • organizational coding:

    • categorizing information based on relationships

Sensory Memory

  • quickly fading

  • iconic: imagery lasts 1 second

  • particularly transient

Short-Term Memory

  • < 60 seconds

  • example: remembering a phone number so that you can put it into a phone but then you can let that memory go after that

  • requires attention and focus

Working Memory

  • rehearsal re-enters info into working memory

  • “chunking:”

    • phone # and SSN

    • people often say they “chunk” those numbers and remember small chunks of numbers to remember them better

Serial Position Effect

  • primacy: first few words

    • example: king, wolf, donut

  • recency: last few words

    • example: frost, century, child

  • the longer there is a time gap, the less accurate it will be

  • working memory is limited — 7 meaningful items!

Long-Term Memory

  • maintaining information over long periods of time

  • language, facts, faces, experiences, skills

Types of Long-Term Memory

  • procedural: gradual learning of skills (practice)

    • example: my ability to play guitar chords

  • semantic: general knowledge of the world facts/concepts

    • example: I know that the storming of the Bastille occurred on July 14, 1789

  • Episodic memory: memory of past experiences (time and place)

    • example: I remember eating gluten-free sushi at a restaurant last night

Consolidation

  • memories most consolidate to be less easily forgotten

    • solidify, combine, turn into a comprehensive whole

    • thinking about it

    • talking about it

    • sleep - getting good sleep helps memories consolidate

    • do dreams play a role?

Hippocampus

  • plays a larger role in memory processes

    • expeirencing bad seizures — hippocampus removal

    • LTM was okay

    • STM was nonexistent

Clive Wearing

  • 1985: clive contracts herpesviral encephlitis

    • degraded his nervous system

    • virtually no new memories

    • some old memories were also impacted

Amnesia

  • anterograde amnesia:

    • failure to store new info

    • HM, Clive Wearing

  • retrograde amnesia:

    • failure to retrieve old memories

Retrieval

  • bringing a memory to mind

    • retrieval cues can help!

    • helpful hints

  • context and anecdotes during encoding impact retrieval

    • moods

    • drugs/alchohol

    • what room you’re in

  • act as retrieval clues!

A Double-Edged Sword

  • retrieval can both be both beneficial and harmful

    • studying - recall of information

    • can reduce recall of related information

    • susceptible to false memories…

When Memory Fails

  • retroactive interference:

    • info learned recently impacts ability to recall earlier knowledge

    • example: calling your ex-girlfriend by your current girlfriend’s name

  • proactive interference:

    • info learned earlier impacts recent knowledge (old impacts new)

    • example: cat always hides in one spot

  • absentmindedness: failure of attention

    • attention is important for encoding/storage

  • blocking: failure of retrieval

    • tip-of-the-tongue

  • memory retrieval can also lead to innaccuracy

  • false memory

  • confidence does not equal accuracy

False Memory

  • Elizabeth Loftus:

    • false memory researcher

    • car study

    • shopping mall lady study

  • memories are extremely malleable

DRM Lists

  • Deese-Roediger-McDermott paradigm (DRM):

    • people falsely remember seeing a word that wasn’t listed

  • lure: “trick”

    • related to the rest of the list

When Memory DOESN’T Fail

  • flashbulb memories:

    • persistence of a negative/arousing memory

      • 9/11

      • outcome of a presidential election

      • COVID lockdown

      • personal examples

The Amygdala

  • Amygdala

  • events/info are easier to remember when they’re:

    • arousing/shocking

    • emotional

    • important for survival

Tips to Improve Memory Recall

  • make it personal/interesting

  • visualization

  • rehearsal

  • consolidate!