Study Notes on Sensation and Perception

Sensation and Perception

  • Sensation: Reception of stimulus energies by sensory receptors and the nervous system.
  • Perception: Organization and interpretation of sensory information to recognize meaningful objects/events.

Sensory Processing

  • Transduction: Conversion of stimulus energies into neural impulses.
  • Bottom-up Processing: Analysis begins at sensory receptors and works up to the brain.
  • Top-down Processing: Information processing influenced by experiences and expectations.

Thresholds

  • Absolute Threshold: Minimum stimulation needed to detect a stimulus 50% of the time.
  • Subliminal: Stimuli below conscious awareness.
  • Difference Threshold: Minimum difference that can be detected between two stimuli.
  • Weber's Law: Difference must be by a constant minimum percentage, varying by stimulus.

Sensory Adaptation

  • Reduced sensitivity due to constant stimulation allows focus on relevant stimuli.

Light and Eye Structure

  • Wavelength: Determines color; distance between light wave peaks.
  • Intensity: Amount of energy in light wave; affects brightness.
  • Eye Components: Cornea, pupil, iris, lens, retina (with rods and cones).
  • Accommodation: Lens shape changes to focus images.

Color Processing

  • Young-Helmholtz Trichromatic Theory: Red, green, and blue cones react to different colors.
  • Opponent-Process Theory: Some cone responses processed by opponent cells.

Perceptual Organization

  • Gestalt Principles: Organizing sensations into whole forms; includes proximity, continuity, and closure.

Depth Perception

  • Ability to see in three dimensions; includes binocular and monocular cues.

Perceptual Constancy

  • Objects are perceived as stable despite changes in sensory input.

Hearing

  • Sound Waves: Compress and expand air molecules; detected by ears.
  • Audition: Process of hearing; involves amplitude (loudness) and frequency (pitch).
  • Decoding: Vibrations transfer from eardrum through inner ear to auditory cortex.

Touch, Pain, and Other Senses

  • Touch: Mixture of pressure, warmth, cold, and pain.
  • Pain Sensitivity: Influenced by various factors and mediated by gate-control theory.
  • Taste: Influenced by basic sensations with survival functions (sweet, salty, sour, bitter, umami).
  • Smell (Olfaction): Chemical sense processed through olfactory receptors.

Kinesthesia and Vestibular Sense

  • Kinesthesia: Sensing position and movement of body parts.
  • Vestibular Sense: Sense of body movement and balance.

Extrasensory Perception (ESP)

  • Claims include telepathy, clairvoyance, precognition; viewed skeptically by scientists.