Sensation and Perception Psychology Chapter 4 Section 1

Sensation and Perception We experience the world through our senses Most people know about the five senses. Can you name them? Vision, hearing, smell, taste, and touch

How many senses do we have? Depending on how you measure it, there could be 20 or so senses Eyes: Rods: how much light there is Eyes: Cones: colors– actually there are three, one for each primary color Ears: there are two with the ears: hearing, balance Skin: five skin senses: heat, cold, pain, itch, pressure Nose: smell Tongue: taste But wait… there’s more…

More senses Muscles/ joints: where our body parts are (thus we can walk without looking down, or touch our fingers with our eyes closed Bladder: tells us when it’s time to urinate Large intestine: tells us when we are full of food We have hunger and thirst sensors We have many other bodily sensations, like when we are about to sneeze or when your leg is tingly when it falls asleep There’s another sense that tells us what position our body is in without us needing to look. (This sense helps a cat land on its feet.) We even have a sense of time So that’s 14- 20 more senses, and there’s still more

The number of senses could total up to a pretty good game of Bingo (pain)

This chart organizes seven of the major senses

Truth or Fiction? Discuss the six statements at the beginning of page 78. Decide if each one is truth or fiction

Sensation and Perception Read Page 77 about Marc What was going on with Marc’s senses in the reading? He tuned out background noise because he was so enamored with Linda’s voice. When Todd stepped on his toe, he was surprised and annoyed, and those intense feelings may have heightened his pain. Then, Linda’s concern seemed to soothe the pain. Psychologists call these two different processes sensation (the feeling) and perception ( the interpretation of the feeling).

Sensation and Perception Once we take in information through our senses, our brain then does something with that information and interprets it The brain might decide whether or not the message is important enough to do something about it What our brain decides depends on many factors: our mood, the circumstances, our cultural background, etc.

While sensations depend on physical ability to sense something, perception relies on the psychological ability to interpret that sensation

Sensation and Perception: The Basics Sensation is the stimulation of sensory receptors and its transmission to the central nervous system The stimulation of the senses is automatic– light, sound, and touch (or chemicals that stimulate smell or taste) are constantly stimulating the receptors

Sensation and Perception: The Basics Perception is the psychological process through which we interpret sensory stimulation Perception reflects learning, expectations, and attitudes, as our brain interprets stimuli

Sensation and Perception Because of our perception skills and experience, we know that the people in the foreground of this picture are NOT that much bigger than the people in the background, despite the sensation produced by the stimulus Sensation and Perception

A Good Test Question Partner up and have the older partner explain the difference between sensation and perception, while the younger one listens. Then have the younger partner explain as the older one listens. I will then choose some random people to explain the difference to the class.

Sensation and Perception: The Basics Sensation and perception are affected by several concepts. Three of these are: Absolute Threshold Difference Threshold Signal Detection Theory

Absolute Threshold Absolute threshold is the very lowest level where we can sense something Typical Thresholds: Vision: A candle flame from about 30 miles away on a dark night Hearing: Ticking of a watch from 20 feet away Smell: One drop of perfume diffused in a small house Taste: One teaspoon of sugar dissolved in two gallons of water Touch: A fly’s wing falling on a cheek from 0.4 inches away

Psychologists often define the absolute threshold as the lowest intensity that a person can detect 50 percent of the time. Anything less than that is subliminal

Difference Threshold Difference threshold is our ability to detect differences between stimuli Can you tell the difference between all these colors?

Signal Detection Theory We focus on whatever we consider important If our best friend were playing piano, we might hear it more than if it were somebody we didn’t know If our nose is stuffy, we don’t taste things as well If there’s noise in the room, we don’t hear as well Signal Detection Theory takes all these outside influences into account when describing how much we sense a stimulus

Sensory Adaptation Sensory Adaptation is the process by which we become more sensitive to weak stimuli and less sensitive to unchanging stimuli If you are in a dark room, your eyes adapt to the amount of light available and pretty soon you can see better If you are on a long car ride, you start to tune out the humming motor after a while If you jump into a pool of hot or cold water, after a while you adapt to it

Sensory Adaptation is sometimes confused with Habituation

Sensory Adaptation Experiment Stare at his nose for 30 seconds and then look at the white space

Assessment Complete Questions 1-3 on page 80