Sensation and Perception

A) 🧠 Psychophysics

• data reduction
  • only set up to process small fraction of possible information & data
  • ex; smells, light, taste, etc
• sensory adaption
  • importance of NEW info
• absolute threshold
  • subliminal perception

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B) 👁️ Vision

• cornea → tough clear membrane over eye
• pupil (iris) → colored part & opening (black) part of eye
• lens → focuses image
• retina (fovea) → thin membrane where seeing happens - point of central focus
• photoreceptors → where seeing starts

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C) 👀 Rods vs cones

• cones → sharper vision, color, high light
  • densely packed in fovea
  • don’t work when it’s dark
• rods → no color, edges less sharp, low light, sense movement
  • none in fovea - dominate peripheral

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D) 🌈 Color vision

• signals with the cones
• young helmholtz trichromatic
  • three types (red, blue, & green)
• color blindness
  • absence of one of the cones
• opponent process theory
  • after-images >> cone fatigue

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E) 🌗 Dark / Light Adaption

• dark to light vs light to dark
• pupils constrict quickly / pupils dilate slowly
• rods “shut down” quickly / rods build up slowly
• dark... mostly “rod-vision”

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F) 👁️ Vision continued

• receptors →
• bipolar cells →
• optic nerve →
• optic chiasm →
• occipital cortex → where the information is funneled to

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G) 🧠 Visual pathways in the brain

• ventral → mentally & cognitively deciding what is it
  • names the object & emotional significance
  • temporal lobe (memory & emotion)
• dorsal → where & how
  • location & movement of object
  • how to locate, avoid, grab
  • parietal lobe (orientation)

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H) 👓 Visual perception

• perceptual organization (Gestalt)
• figure vs ground
  • what’s important & what’s background info → first task
• organizational grouping Gestalt
• nearness
  • close things grouped together
• similarity
  • similar things grouped
• continuity
  • similar patterns go together
• closure
  • see wholes, not pieces

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I) 👓 Depth perception

• binocular → true depth perception - only goes a few yards
  • brain creates perception of depth
• mule depth perception → seeing in 3d
• based on stereoscopic vision (retinal disparity)

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J) 👁️ Monocular cues

• general sense of where object is
  • doesn’t depend on two eyes
• linear perspective
• relative size
• relative height
  • far away = higher on horizon
• overlap & interposition
  • blocking other objects
• relative clarity, brightness, texture

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K) 👁️ Perception & Attention - Data Reduction cont.

• perceptual sets & expectations
• selective attention & sensory adaptation
  • what do I really need to focus on

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Pitch

• separates high & low (place code)
  • high → short & fast
  • low → long & slow
• pitch effects place on basilar membrane which corresponds to place on auditory cortex
• temporal code (ion frequency)
  • rate of neural firing

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Hearing loss

• one of our weakest senses - hasn’t evolved
• conductive hearing loss
  • damage to the parts & to the hair nerve cells
  • ex; hunters notch - can become deaf to a singular sound
  • hearing aids
• sensorineural (nerve) deafness
  • typically born with or develops
  • signal not getting from cochlea to brain
  • cochlear implant

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Issues with restored senses

• perception is a learned task
  • forming & rewiring neural nets
• when young, our brain is very flexible
• problems with restoring senses at older ages

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Touch

• three separate systems
  1. pressures
  2. textures
  3. patterns
  4. thermoreceptors
• hands & face have most receptors

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Pain

• separate sets of neurons
• diverse in triggers & receptors
• have pain receptors internally & externally
• ability to sense pain keeps us alive
• pain is something our mind creates
  • ex; phantom limb pain
  • ex; referred pain

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Pain control

• OTC’s block some neurotransmitters
• opiates (including endorphins) block signals
• gate theory → acupuncture interferes with the signal
  • distraction, relaxation, positive thoughts

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Smell & Taste

• least important & understood

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Behaviorist perspective

• psychology = science
• based on observations
• psychology should focus on observable behavior
• extreme: nothing but behavior matter

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Conditioning = basis of learning

• learning or associating
• classical → associating 2 stimuli
• operant → associating responses & consequences

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Classical conditioning vocab

• classical conditioning → neutral stimulus (CS) evokes a response (CR) after being associated w/a stimulus (US) that naturally evokes the response (UR)

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Classical conditioning - other examples

• phobias
  • ex; little Albert → gave a child a stuffed animal, every time he’d reach for it, a loud noise would play - eventually he was terrified of the stuffed animal
• aversions
• “food allergies”
• likes & fetishes

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Classical conditioning graph

acquisition (CS + US) → extinction (CS alone) → spontaneous recovery of CR → extinction (CS alone)
pause

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Stimulus generalization

• stimulus similar to CS elicits response

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Discrimination

• distinguish between stimuli

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Higher order conditioning

• another CS paired to original CS

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Aversive or counter conditioning

• pairing new US to old CS to change the CR

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Example

• old: CS (cigs) → CR (feel good)
• new: CS (cigs) + US (shock) → UR (pain/avoid)
• finally: CS (cigs) → CR (pain/avoid)