sensation and perception Flashcards
define perception
staged process of sensing, understanding, identifying, recognizing and preparing reactions to sensation
define transduction
conversion of one form of energy to another form of energy ex. light to neural impulses
stages of perception
- sensation - external stimuli trigger action potentials of sensory neurons that travel to the brain
- perceptual organization - process of synthesizing sensory features into internal representations of an external stimulus
- identification and recognition - process of creating perception by identifying and assigning meaning to perceived sensation
thresholds of transduction
- absolute threshold - minimum amount of physical energy needed to produce a sensory experience
- difference threshold - magnitude of difference between sensations required for stimuli to be considered different
- just-noticeable difference - a measure of how different the intensity of a stimulus has to be before an individual can tell it has changed
- sensory adaptation - diminishing responsiveness of sensory systems including transduction to prolonged stimulus input
Which area of the brain does the first level visual association cortex occur?
adjacent areas of occipital lobe
which area of the brain does the second level visual association cortex occur?
parietal and temporal lobe
which area of the brain does sensory relay occur?
thalamus
which area of the brain does motion (motion agnosia), depth and brightness occur?
magnocellular channel
which part of the brain does colour, form and texture (visual agnosia and propagnosia) occur?
parvocellular channel
theories of colour vision
- duplicity - cones (colour vision) rods (night vision)
- trichomatic - suggests thall there are 3 types of colour receptors (primary colors) and all other colors are additive/subtractive combinations of the three
- opponent process theory - suggests all colour experiences arise from relative differences in the stimulation of 3 types of cones (short, medium, long)
categories of colour blindness
- rod monochromats- non functional cones, poor visual acuity, shades of gray
- tritanopia - defective short cones, insensitive to blue and yellow
- deuteranopia - defecive medium cones, insensitive to green
- protanopia - defective long cones, inability to distinguish red and purple
elements of sounds
- frequency - number of cycles the wave completes in a given time
- amplitude - strength of the sound wave
- pitch - highness or lowness of sound
- loudness - amplitude of the sound wave
- timbre - perceived complexity of a sound
transduction for hearing
- basilar membrane vibrates and produces shearing action to the cilia, attached to the techtorial membrane, bend
- bending action allows potassium to flow from cell facilitating action potentials in the spiral ganglion cells that travel to the auditory nerve and then to auditory cortex
- travelling waves within cochlea
- high frequency waves collapse early (base)
- low frequency waves collapse later (apex)
- there is an orderly layout of frequency coding along basilar membrane cells
- volley principle allows us to use the orderly layout to perceive sounds beyond 1000 Hz
transduction for smell
- receptors in olfactory cilia embedded in olfactory mucosa that send neural impulses to the olfactory bulb
- up to 1000 different molecules can stimulate receptors
- odours based on complex coding
- activity passed to olfactory bulbs and then to limbic system
transduction for taste
- soluble chemical substances
- taste bud receptors located within trenches of papillae or tongue
- microvilli make contact with saliva
- different types of molecules stimulate receptors for sour, sweet, salty, bitter and umami (savoury)
- different papillae contain different distributors of receptors
somatosensory senses
skin senses, internal senses, vestibular senses
gate control theory of pain
suggests that cells in the spinal cord act as neurological gates, interrupting and blocking pain signals and allowing others to get through to the brain
neuromatrix theory of pain
incorporates the reality that people experience pain without a physical cause
laws of perceptual grouping
- law of proximity - we group together the nearest elements of a stimuli
- law of similarity - we group together the most similar elements of stimuli
- law of good continuation - we experience stimule as continuous even when they are interrupted
- law of closure - we fill in small gaps to experience stimuli as wholes
- law of common fate or region - we group together stimuli that are moving in the same direction or regionally grouped
elements of perceptual learning
attention - a state of focused awareness on a subset of the available perceptual information
figure - object-like regions of the visual field that are distinguished from the background
ground - background areas of visual field, against which figures stand out
spatial/temporal - information is combined from fixations of different locations in space or time
integration
constancies - perception involves inferential problem solving that often depends on learned biases that some things remain constant
types of perceptual learning
bottom up or data driven - analysis and integration basic features into a perceptual unit
hierarchial organization - formation of perceptual units through increasingly complex connections between simple units
conceptually driven processing - the use of concept to guide perception
