Ch 5

• Our senses help us make contact with the external world and add to happiness, variety, and satisfaction in life
• We have five sense organs: eye, ear, skin, nose, and tongue
• If we couldn't see colors, beauty, pictures, or traffic lights, our life would become dull and risky
• We derive sensual pleasure from breathing fresh air, enjoying tasty food, good music, and feeling relaxed by touching animals
• Sensation is the process by which neutral impulses are created by stimulation of sensory neurons, resulting in awareness of conditions inside or outside the body
• Perception refers to the elaboration and interpretation of sensory experiences, influenced by past and present experiences
• Vision:

  • Vision is extremely important for humans and animals
  • Sir Isaac Newton discovered that white light separates into a rainbow of colors when passing through a prism
  • Color blindness is the partial or total inability to distinguish colors
• Hearing:

  • Sounds are created when objects vibrate and push molecules of a medium back and forth
  • Frequency refers to the number of cycles a wave completes in a given time
  • Pitch is determined by frequency, high frequencies produce high pitch and low frequencies produce low pitch
• Vestibular Sense:

  • Sense of bodily orientation with respect to gravity
  • Tells us how our heads are positioned and if we are moving
• Kinesthetic Sense:

  • Sense of body position and movement of body parts relative to each other
  • Provides sensory feedback about motor activities
• Olfaction (Sense of Smell):

  • Involves biochemical activities triggering neural impulses
  • Neural impulses convey odor information to the brain
• Gustation (Sense of Taste):

  • Taste receptor cells are gathered in taste buds on the upper side of the tongue
  • Four primary taste qualities: sweet, sour, bitter, and saline
• Skin Senses:

  • Nerve endings in the skin produce sensations of cold, warmth, or pressure
  • Sensitivity to pressure is maximum on the face, tongue, and hands
• Pain:

  • Pain is the body's response to stimulation from noxious stimuli
  • Acute pain is a reaction to sharp or sudden stimulation
• Perception:

  • Brain actively selects, organizes, and integrates sensory information to create a picture of the world
  • Perception involves synthesis of simple sensory features into a percept of an object
• Figure-Ground Organization:

  • Sensations are grouped into objects or figures that stand out on a planar background
  • Figure always defines the ground and the ground defines the figure
• Laws of Perceptual Grouping:

  • Proximity: stimuli near each other tend to be grouped together
  • Similarity: stimuli that are similar tend to be grouped together
  • Continuity: events close in time and space are perceived together
• Perceptual organization principles:

  • Events close in time and space are perceived together
  • Similar stimuli in size, shape, or color tend to be grouped together
  • Continuity perception tends towards simplicity and continuity
  • Closure is the tendency to complete an incomplete figure with a consistent overall form
  • Common region stimuli tend to be seen as a group
• Perceptual constancy:

  • Perception of an object's shape, size, or brightness remains the same even though its image on the retina has changed
  • Size constancy: perceived size of an object remains the same even though the size of its image on the retina changes
  • Shape constancy: shape of an object remains stable even though the shape of its retina image changes
  • Brightness constancy: brightness of objects appears to stay the same as lighting conditions change
• Depth perception:

  • Ability to see three-dimensional space and accurately judge distances
  • Depth cues can be monocular or binocular
  • Monocular cues work with one eye, while binocular cues require two eyes
  • Binocular cues are caused by retinal disparity, a discrepancy in images reaching the left and right eyes
• Extra sensory perception (ESP):

  • Abilities to perceive objects or events in ways that cannot be explained by known sensory capacities
  • Parapsychology studies ESP phenomena
  • Examples include telepathy, precognition, and psychokinesis
• Applications of perception in everyday life:

  • Eyewitness testimony can be prone to errors due to perceptual distortions
  • Perceptual awareness and positive psychology influence how people perceive themselves and others
  • Paying attention and breaking perceptual habits can lead to better outcomes
• Summary of sensation and perception:

  • Sensation is the process of creating neural impulses from sensory stimulation, resulting in awareness of internal or external conditions
  • Five main senses: sight, hearing, touch, smell, taste, with additional vestibular and kinesthetic senses
  • Perception involves forming an internal representation of an object by synthesizing simple sensations and assigning meaning
  • Principles of perceptual organization include nearness, similarity, continuity, and closure to identify figures against the background
• • Depth perception involves judging distance and perceiving three-dimensional space using monocular and binocular cues
  • Perceptual constancy refers to interpreting familiar objects with the same size, shape, or color despite sensory input suggesting otherwise
  • Illusions are distorted perceptions of existing stimuli, while hallucinations are perceptions of non-existent objects or events
• Sensation can be explained as a process by which one form of energy is converted to another