Sensation and Sensation and PerceptionPerception
Grab a scrap sheet of paper
Write down your definition of sensationperception
SensationSensation
The process by which our The process by which our sensory systems (eyes, ears, sensory systems (eyes, ears, and other sensory organs) and other sensory organs) and nervous system receive and nervous system receive stimuli from the environmentstimuli from the environment
A person’s awareness of the A person’s awareness of the worldworld
SensationSensation Input comes from the five Input comes from the five
senses:senses:Visual (Eyes)Visual (Eyes)Hearing (Ears)Hearing (Ears)Touch (Skin)Touch (Skin)Smell (Nose)Smell (Nose)Taste (Tongue)Taste (Tongue)
PerceptionPerception
The process of integrating, The process of integrating, organizing and interpreting organizing and interpreting sensations.sensations.
Sensory ReceptorsSensory Receptors
Specialized cells unique to each Specialized cells unique to each sense organ that respond to a sense organ that respond to a particular form of sensory particular form of sensory stimulation.stimulation.
Sensory Receptors: ExampleSensory Receptors: Example
A combination of your senses. When you A combination of your senses. When you bite into a crisp apple, you hear the crunch, bite into a crisp apple, you hear the crunch, you taste the sweetness, you feel the you taste the sweetness, you feel the smooth skin, you see the red, and you smell smooth skin, you see the red, and you smell the aroma.the aroma.
TransductionTransductionThe process by The process by
which a form of which a form of physical energy is physical energy is converted into a converted into a coded neural coded neural signal that can be signal that can be processed by the processed by the nervous system. nervous system.
What is a What is a Threshold?Threshold?
ThresholdThreshold
An edge or a boundaryAn edge or a boundaryWalking into the room – on one side Walking into the room – on one side
you are in the room on the other you you are in the room on the other you are outside of the roomare outside of the room
Absolute ThresholdAbsolute Threshold
The smallest possible The smallest possible strength of a stimulus that strength of a stimulus that can be detected half the can be detected half the time.time.
Absolute Threshold ExampleAbsolute Threshold ExampleTouch: The wing of a bee
falling on your cheek from a height of 1 centimeter
Absolute Threshold ExampleAbsolute Threshold ExampleHearing: The tick of a watch
from 6 meters away
Absolute Threshold ExampleAbsolute Threshold Example
Taste: 1 gram of table salt in 500 Taste: 1 gram of table salt in 500 liters of water – the minimum liters of water – the minimum needed to taste somethingneeded to taste something
Absolute ThresholdAbsolute Threshold
Vision:Vision: A candle flame on A candle flame on a clear night, 30 miles away a clear night, 30 miles away – the minimum needed to – the minimum needed to see it. Doesn’t mean that see it. Doesn’t mean that you can make out what it isyou can make out what it is
Absolute Threshold ExampleAbsolute Threshold ExampleSmell: 1 drop of perfume in a 3 Smell: 1 drop of perfume in a 3
room house.room house.
Weber’s Law Weber’s Law
The greater the magnitude of the The greater the magnitude of the stimulus, the larger the stimulus, the larger the difference must be in order to be difference must be in order to be noticednoticed
ExamplesExamplesWhen you can detect the difference When you can detect the difference
in volume of musicin volume of musicWhen you can detect the difference When you can detect the difference
in pressure on your armin pressure on your arm
Weber’s Law ExampleWeber’s Law Example If you are carrying 20 lbs. and add 5 If you are carrying 20 lbs. and add 5
lbs., it’s noticeable. If you are lbs., it’s noticeable. If you are carrying 100 pounds and add 5 carrying 100 pounds and add 5 pounds, it may not be noticeable. pounds, it may not be noticeable. You need to add 10 lbs. to 100 You need to add 10 lbs. to 100 pounds to make it noticeable.pounds to make it noticeable.
Just Noticeable Difference ThresholdJust Noticeable Difference Threshold
The minimum difference that a The minimum difference that a person can detect between two person can detect between two stimuli 50% of the time.stimuli 50% of the time.
Sensory AdaptationSensory AdaptationWhen exposed to a stimuli over When exposed to a stimuli over
a period of time there will be a a period of time there will be a diminished sensitivity to itdiminished sensitivity to it
If a stimulus is constant and If a stimulus is constant and unchanging, eventually a person unchanging, eventually a person may fail to respond to itmay fail to respond to it
Example of Sensory Adaptation Example of Sensory Adaptation A hot tub – after a certain period A hot tub – after a certain period
of time no longer seems as hotof time no longer seems as hot
Selective AttentionSelective AttentionFocusing conscious awareness on a Focusing conscious awareness on a
particular stimulus (sense) to the particular stimulus (sense) to the exclusion of othersexclusion of others
Selective Attention ExampleSelective Attention ExampleWalking Walking
down the down the hallway – all hallway – all 5 senses are 5 senses are firing. What firing. What grabs your grabs your attention?attention?
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