Chapter 5 psychology

• Sensation


  The physical process of sensory receptors detecting stimuli
• Perception


  The psychological process of interpreting and organizing sensory information
• Sensory receptors


  • Specialized neurons that respond to specific types of stimuli
  • Convert sensory stimulus energy to action potentials (transduction)
• Senses


  • Vision
  • Hearing (audition)
  • Smell (olfaction)
  • Taste (gustation)
  • Touch (somatosensation)
  • Balance (vestibular)
  • Body position and movement (proprioception and kinesthesia)
  • Pain (nociception)
  • Temperature (thermoception)
• Absolute threshold


  The minimum amount of stimulus energy that must be present for the stimulus to be detected 50% of the time
• Sensory receptors can detect very small stimuli, e.g. a candle flame 30 miles away or the tick of a clock 20 feet away
• Subliminal messages


  Messages presented below the threshold for conscious awareness
• Just noticeable difference (JND) or difference threshold

  The minimum difference in stimuli required to detect a difference
• Weber's law


  The difference threshold is a constant fraction of the original stimulus
• Bottom-up processing


  Sensory information from a stimulus in the environment driving a process
• Top-down processing


  Knowledge and expectancy driving a process
• Bottom-up processing


  Attentional capture, involuntary and fast
• Top-down processing


  Goal-directed, slow, deliberate, effortful, and under conscious control
• Sensation is the physical process, while perception is the psychological process of interpreting sensations
• Top-down processing


  • Goal directed, slow, deliberate, effortful, and under your control
• Sensation


  Physical process
• Perception


  Psychological process
• Sensation


  Precedes perception
• Not all sensations result in perception
• Sensory adaptation


  Failure to perceive stimuli that remain relatively constant over prolonged periods of time
• Attention


  Plays a significant role in determining what is sensed versus what is perceived
• Signal detection theory


  Ability to identify a stimulus when it is embedded in a distracting background
• Perceptions can be affected by beliefs, values, prejudices, expectations, and life experiences
• Westerners more prone to experience certain visual illusions than non-Westerners, and vice versa
• Carpentered world


  Perceptual context of buildings with straight lines
• Ability to identify odors, rate pleasantness and intensity varies cross-culturally
• Thrill-seeking personality


  More likely to show taste preferences for intense sour flavors
• Positive attitudes toward reduced-fat foods


  More likely to rate reduced-fat foods as tasting better
• Amplitude


  The distance from the center line to the top point of the crest or the bottom point of the trough
• Wavelength


  The length of a wave from one peak to the next
• Wavelength


  Directly related to the frequency of a given wave form
• Frequency


  The number of waves that pass a given point in a given time period, often expressed in hertz (Hz) or cycles per second
• Longer wavelengths


  Have lower frequencies
• Shorter wavelengths


  Have higher frequencies
• Visible spectrum


  The portion of the larger electromagnetic spectrum that humans can see
• The visible spectrum in humans is associated with wavelengths that range from 380 to 740 nm</b>
• Honeybees can see light in the ultraviolet range, and some snakes can detect infrared radiation in addition to more traditional visual light cues
• Light wavelength


  Associated with perception of color
• Longer wavelengths are associated with perception of red, intermediate wavelengths with greens, and shorter wavelengths with blues and violets
• Light wave amplitude


  Associated with perception of brightness or intensity of color