Sensation and Perception

    Subdecks (3)

    Cards (83)

    • sensation
      stimulus detection process by which our sense organs respond to and translate environmental stimuli into nerve impulses which are sent to the brain
    • perception
      making sense of what our senses tell us
    • sensation systems
      designed to extract from the environment the information we need to function and survive
    • psychophysics
      area that studies relations between the physical characteristics of stimuli and sensory capabilities
    • absolute threshold
      lowest intensity at which a stimulus can be detected 50% of the time
    • decision criterion
      a standard of how certain they must be that a stimulus is present before they say they detect it
    • signal detection theory
      factors that influence sensory judgement e.g. fatigue, expectation and significance of stimulus
    • subliminal stimuli
      weak or brief stimuli that is received by senses but cannot be perceived consciously
    • difference threshold
      smallest difference between two stimuli that people can perceive 50% of the time- just noticeable difference
    • Weber's law
      difference threshold is directly proportional to the magnitude of the stimulus with which the comparison is being made
    • sensory adaptation
      diminishing sensitivity to an unchanging stimulus- occurs in all senses, allows our senses to pick up informative changes in the environment that could be important to survival
    • sensory transduction
      process whereby characteristics of a stimulus are converted into nerve impulses
    • vision
      stimulus is electromagnetic energy (light waves)
      sensitive to different wave lengths (400-700)
      different wavelengths of visible light have different colours
    • pupil
      behind cornea- controls how much light can enter eye
    • lens
      flexible structure- thinner to focus on distant objects, thicker on closer objects
      causes images to be focused on inner surface of the eye (retina)
    • myopia
      near sighted- visual image focused in front of retina, eyeball is longer than normal
    • hyperopia
      farsightedness- image is focused behind retina, lens doesn't thicken enough
    • photoreceptors
      retina, rods, cones, fovea
    • retina
      multi-layered light sensitive tissue at the rear of fluid filled eyeball- contains to types of receptor cells
    • rods
      black and white brightness receptors- function best in dim light
    • cones
      colour receptors- function best in bright illumination
    • fovea
      small area in centre of retina-no rods but densely packed cones- responsible for more detailed vision
    • rods and cones have synaptic connections with bipolar cells
      connected to ganglion cells
      axons are collected into a bundle, forms optic nerve
      absence of receptors where optic nerve exits the eye creates a blind spot
    • visual process
      lens reverses image
      photoreceptors and neurons send input to the brain, reconstructs it in right direction
      many rods are connected to one bipolar/ganglion cell as each photoreceptor can only respond to lights in its vicinity
    • visual transduction
      protein molecules allow rods and cones to translate light waves into nerve impulses
      produces a chemical reaction that changed rate of neurotransmitter release
      greater the change, stronger the signal passed to bipolar and ganglion cells
    • dark adaptation
      progressive improvement in brightness sensitivity that occurs over time under conditions of low illumination
    • analysis and reconstruction
      from retina- optic nerve sends message to thalamus
      input is routed to the primary visual cortex in the occipital lobe
    • feature detectors
      cells within primary visual cortex that fire selectively in response to visual stimuli that have specific characteristics
    • visual association cortex
      combines and interprets information
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