Myers EXPLORING PSYCHOLOGY (6th Edition in Modules)

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Myers EXPLORING PSYCHOLOGY (6th Edition in
Modules)

• Module 11
• Introduction to Sensation and Perception Vision
• James A. McCubbin, PhD
• Clemson University
• Worth Publishers

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Sensation

• Sensation
• the process by which our sensory receptors and
  nervous system receive and represent stimulus
  energy
• Perception
• the process of organizing and interpreting
  sensory information, enabling us to recognize
  meaningful objects and events

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Sensation

• Our sensory and perceptual processes work
  together to help us sort out complex images

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Sensation

• Bottom-Up Processing
• analysis that begins with the sense receptors and
  works up to the brains integration of sensory
  information
• Top-Down Processing
• information processing guided by higher-level
  mental processes
• as when we construct perceptions drawing on our
  experience and expectations

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Sensation Basic Principles

• Psychophysics
• study of the relationship between physical
  characteristics of stimuli and our psychological
  experience of them
• Light- brightness
• Sound- volume
• Pressure- weight
• Taste- sweetness

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Sensation Thresholds

• Absolute Threshold
• minimum stimulation needed to detect a particular
  stimulus 50 of the time
• Difference Threshold
• minimum difference between two stimuli required
  for detection 50 of the time
• just noticeable difference (JND)

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Sensation Thresholds

• Subliminal
• when stimuli are below ones absolute threshold
  for conscious awareness

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Sensation Thresholds

• Webers Law
• to be perceived as different, two stimuli must
  differ by a constant minimum percentage (rather
  than a constant amount)
• light intensity- 8
• weight- 2
• tone frequency- 0.3

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Now you see it, now you dont!
Sensory Adaptation- diminished sensitivity as a
consequence of constant stimulation
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Vision

• Transduction
• conversion of one form of energy to another
• in sensation, transforming of stimulus energies
  into neural impulses
• Wavelength
• the distance from the peak of one wave to the
  peak of the next

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Vision

• Hue
• dimension of color determined by wavelength of
  light
• Intensity
• amount of energy in a wave determined by
  amplitude
• brightness
• loudness

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The spectrum of electromagnetic energy
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Vision Physical Properties of Waves
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Vision
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Vision

• Accommodation- the process by which the eyes
  lens changes shape to help focus near or far
  objects on the retina
• Retina- the light-sensitive inner surface of the
  eye, containing receptor rods and cones plus
  layers of neurons that begin the processing of
  visual information

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Retinas Reaction to Light- Receptors

• Rods
• peripheral retina receptors
• detect black, white and gray
• for peripheral or twilight conditions
• Cones
• receptors near center of retina
• fine detail and color vision
• for daylight or well-lit conditions

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Retinas Reaction to Light

• Optic nerve
• nerve that carries neural impulses from the eye
  to the brain
• Blind Spot
• point at which the optic nerve leaves the eye,
  creating a blind spot because there are no
  receptor cells located there

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Vision Receptors
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Pathways from the Eyes to the Visual Cortex
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Visual Information Processing

• Feature Detectors
• nerve cells in the brain that respond to
  specific features
• shape
• angle
• movement

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Visual Information Processing

• Parallel Processing
• simultaneous processing of several aspects of a
  problem simultaneously

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Visual Information Processing

• Trichromatic (three color) Theory
• Young and Helmholtz
• three different retinal color receptors
• red
• green
• blue

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Visual Information Processing

• Opponent-Process Theory- opposing retinal
  processes enable color vision
• ON OFF
• red green
• green red
• blue yellow
• yellow blue
• black white
• white black

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Visual Information Processing

• Color Constancy
• Perceiving familiar objects as having consistent
  color, even if changing illumination alters the
  wavelengths reflected by the object

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Color-Deficient Vision

• People who suffer red-green dificiency have
  trouble perceiving the number within the design

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Opponent Process Afterimage Effect