sensation and perception · 2020. 11. 15. · sensation and perception ... 37
Sensation and Perception Gateway to the outside world.
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Transcript of Sensation and Perception Gateway to the outside world.
Sensation and PerceptionGateway to the outside world
Definitions Sensation
The stimulation of sensory receptors and the transmission of sensory information to the Central Nervous System
Perception The psychological
process through which we interpret sensory information
Definitions Absolute threshold
The weakest amount of stimulus that can be sensed
Difference threshold The minimum amount
of difference that can be detected between two stimuli
Absolute Threshold
Definitions
Sensory adaptation The process by which
we become more sensitive to weak stimuli and less sensitive to unchanging stimuli
Definitions Signal-Detection
Theory The method of distinguishing
sensory stimuli that takes into account not only the stimuli’s strengths but also such variable elements as the setting, your physical state, your mood, and your attitudes
Vision How does sight work? What are the main parts of the eye? How does color vision work? What is color blindness and what causes
it?
Vision Vision accounts for
80% of the sensory information processed by the brain
The key component of vision is light
Vision Light is comprised of
electromagnetic waves
The human eye sees a small portion of the spectrum of wavelengths
Visible light can be broken down into its key components
Vision In order from
shortest to longest: red, orange, yellow, green, blue, indigo, violet
The nonvisible ranges include ultraviolet and infrared
Parts of the Eye Pupil
Controls the amount of light that enters the eye
Lens The lens controls the
clarity of the image Retina
The surface upon which the image is projected
Parts of the Eye Photoreceptors
Neurons which are sensitive to light
Information is transmitted via the photoreceptors to the brain
Rods Sensitive to the brightness
of light
Cones Cones provide color vision
Vision
Definition Visual acuity
The sharpness of an image which is determined by the ability to see visual details in normal light
Measured by a Snellen Chart
Vision Measured against
a distance of 20 feet
Numbers show what a person would see against a normal person’s vision
Farsighted vs. nearsighted
Vision Afterimages
Visual impression that remains after the original image is removed
Blind spot Area vision which
is blocked by lack of photoreceptors
How vision works
Color Blindness Some people are unable
to see normal color vision Due to the absence or
malfunction of the cones Most common (99%) is
red-green in which person has difficulty seeing shades of red or green
8% of males and 1% of females
Hearing What two characteristics do every sound
have? What are the main parts of the ear and
how do they work? What are some causes of deafness?
Sound Pitch
How high or low a sound is (frequency)
The frequency depends on the number of cycles per second
The more cycles, the higher the pitch
Sound Pitch is measured in Hertz (Hz) Over the course of time, we lose the
ability to hear different frequency. At age 25, you begin to lose your
ability to hear over 15,000 Hz Take the test
http://www.noiseaddicts.com/2009/03/can-you-hear-this-hearing-test/
Sound Loudness
The loudness of a sound is determined by the height of the sound wave
This is known as the amplitude
Loudness is measure in decibels (dB)
Sound Loudness can be
subjective A person’s
sensitivity to sound and the duration can influence perceived loudness
The Ear
The Ear Pinea
Outer flap of tissue that is use to help funnel the sound to the eardrum
Eardrum A thin membrane that
vibrates when sound hits it Hammer, Anvil, & Stirrup
Small bones in the middle ear which transmit the sound to the inner ear
Stirrup is smallest bone in the body
The Ear Cochlea
Bony tube in the ear that contains the fluids and neurons needed to transmit sounds to the brain
Auditory nerve Nerve that transmits
neural impulses from the inner ear to the brain
Locating Sound Determining
locations of sounds is based upon the principles of stereo sound
The level measured in each ear helps to determine where the sound originated
Deafness May be inherited
or caused by injury, disease or old age
Two primary types of deafness Conductive Sensorineural
Conductive Deafness Occurs due to
damage to the middle ear
Usually aided by devices that amplify sound
Happens when the eardrum is ruptured or through aging
Sensorineural Deafness Caused due to damage
in the inner ear May be mild, moderate
or severe Can be born this way or
due to prolonged exposure to loud sounds
Can be aided by cochlear implants