sensation and perception -...
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Sensation and PerceptionI. Sensation vs. PerceptionSensation and perception are often discussed as separate topics. However, it is oftendifficult to determine where one ends and the other begins.
l Sensation
l Perception
II. The Nature of Sensation
The Basic Process
l Receptor cells
l Doctrine of specific nerve energies
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Sensory Thresholds
l Absolute threshold
The following are examples of the sensitivity of our senses:
l Taste:
l Smell:
l Touch:
l Hearing:
l Vision:
Sensory Thresholds
l Sensory adaptation
l Difference threshold
– Just noticeable difference (JND)
l Weber’s Law
3
III. The Sensesl What senses do we possess?
VisionVision is such an important sense in humans, it often supersedes what our other sensesmay be telling us.
Visible Spectrum of Electromagnetic Energy
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The Visual Systeml Cornea
l Iris
l Pupil
l Lens
l Retina
l Fovea
Receptor Cellsl Rods
l Cones
l Bipolar cells
l Ganglion cells
l Blind spot
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Adaptationl Dark adaptation
l Light adaptation
l Afterimage
From Eye to Brain
l Optic nerve
l Optic chiasm
The Nature of Waves
l Waves produced by energy (e.g., light,sound, radiation) can be described by:
– wavelength
– amplitude
– complexity
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Color Visionl Properties of color
– Hue
– Saturation
– Brightness
Theories of Color Vision
l Trichromatic theory
– Three different types of cones
– Experience of color is the result of mixing of the signals from these receptors
– Can account for some types of colorblindness
l Dichromats
l Monochromats
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l Trichromatic theory cannot explain all aspects of color vision:
l Opponent-process theory
– Three pairs of color receptors
– Members of each pair work in opposition
Color Vision in Other Speciesl Other species see colors differently than humansl Most other mammals are dichromatsl Rodents tend to be monochromats, as are owls who have only rodsl Bees can see ultraviolet light
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Hearing
Soundl Sound waves
l Frequency
l Amplitude
l Complexity
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The Ear
l Eardrum
l Middle ear
l Oval window
l Cochlea
l Basilar membrane
l Auditory nerve
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Theories of Hearingl Place theory
l Frequency theory
– Volley Principle
Hearing Disorders
Hearing Damage
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IV. The Other Senses
Smell
l Detecting common odors
l Anosmia
l Pheromones
l Vomeronasal organ (VNO)
Taste
l Basic tastes
l Recent discovery of fifth taste
l Taste buds
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The Other Senses
Kinesthetic Sensesl Stretch receptors
– Golgi tendon organs sense movement of tendons
Vestibular Senses
The Skin Senses
l Pressure, temperature, and pain receptors
Painl Gate control theory
l Biopsychosocial theory
l Placebo effect
l Alternative approaches to pain relief
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