Sensation and Perception Psych 1 Chapter 4

Sensory processes Processing, interpreting, and organizing the information our senses take in Sensation- receiving info from the environment through our 5 senses Perception- interpreting the info that is received and making it meaningful Sensation- sensory strip Perception- parietal lobe

Absolute threshold The level of sensory stimulation necessary for sensation to occur 50% of the time Absolute threshold tested for each of the 5 senses

Absolute threshold examples Vision- candle light seen at 30 miles away on a clear night Hearing- tick of a watch under quiet conditions at 20 feet away Touch- bee’s wing falling on your cheek from 1 cm above Smell- 1 drop of perfume diffused in a 3 bedroom apartment Taste- 1 teaspoon of sugar in 2 gallons of water

Difference thresholds Also- Just Noticeable Difference The minimum amount of difference (or change) in stimulation we can detect 50% of the time There are difference thresholds for each of the 5 senses Not predetermined like the absolute thresholds Vary for each person Difference thresholds are about the change in the proportion of the difference, not the change in the amount

Adaptation Our unconscious process of ignoring unimportant sensory info Allows us to deal with environments containing large amounts of stimuli Without adaptation we would be continuously distracted and unfocused Also- sensory adaptation/habituation

Selective attention The focusing of conscious awareness on a particular stimulus Can you feel your shoes? Watch? Earrings? Cocktail party effect Driving experiments

Inattentional blindness Failure to see visible objects when our attention is directed elsewhere Gorilla/basketball experiment http://www.youtube.com/watch?v=vJG698U2Mvo

Change blindness Failing to notice changes in the environment Speed date experiment from Dateline Giving directions experiment

Your assignment!!! Complete the sensory processes worksheet For difference threshold, develop your own examples of when you think you would notice a difference for each of the 5 senses On the back, create a comic strip in which your characters display inattentional blindness and change blindness 4 squares each (4- inattentional, 4- change) Dialogue or captions that explain why this is an example of each Color

Perceptual constancies 5 areas of perception our mind does not change, we hold them steady to keep order and make sense of the world

Perceptual constancies Size- ability to retain the size of an object no matter where it is located Ex: Cars are not smaller because they are farther away from you Color/brightness- the ability to see objects as the same color or brightness no matter the environment Ex: Grass looks darker at night but we know it is the same color

Perceptual constancies Shape- the ability to perceive an object as having the same shape regardless of at which angle we are viewing it Ex: a door- whether open or close we know it is the same shape even though it looks different Space- the ability to keep objects in the environment steady by perceiving either ourselves or the object as moving Ex: driving in a car- focus on you moving or the outside moving, not both

Depth perception Each eye sends a slightly different message to the brain (think split brain patients) This difference is called retinal disparity Allows us to see depth Visual cliff and babies- proves we have depth perception early in life

Perceptual organization Our ability to view pieces of information into an organized whole

Optical Illusions An inaccurate perception Famous types of illusions: Muller-Lyer illusion: Reversible figure:

Extra sensory perception Beyond the normal level of awareness A “feeling” something is wrong or familiar Lack of scientific knowledge to prove ESP exists Only information we have is from those who feel they have ESP- not a valid source

Types of ESP Mental telepathy- communication through thoughts from one brain to another Clairvoyance- seeing in the distance Precognition- predicting the future Psychokinesis- ability to move or alter an object by thought alone

The 5 senses Vision Hearing (audition) Touch (cutaneous senses) Smell (olfaction) Taste

Vision Dominate human sense- we believe what we see first, our other senses are secondary Depends on energy- light waves

Major parts of the eye Cornea- outer covering

Major parts of the eye Iris- colored muscle, regulates amount of light let in Pupil- opening

Major parts of the eye Lens- focuses the image onto the retina

Major parts of the eye Nearsightedness and farsightedness

Major parts of the eye Retina- back of the eye, contains light receptors Fovea Red eye?

Major parts of the eye Optic nerve- bundle of cells, carries message from eye to brain Where do the messages get sent to in the brain??

Major parts of the eye

Major parts of the eye Rods- night vision, sees black and white Cones- day vision, sees color Both located on the retina

Color vision All colors we see are a mix of red, green, and blue Defects- Color blind- see only certain color ranges May struggle with shades of red, or shades of blue, or shades of green 8% males, 5% females True color blind- can’t see color at all, only the rods are working, very sensitive to light

After images When we focus on an image, the chemicals in our cones are used When we look away, the unused chemicals are released to restore balance in the cones This causes an after image of opposite colors

After images

Hearing Depends on energy, sound waves Auditory nerve carries messages of sound into the brain

4 characteristics of sound: 1. pitch- how high or low a sound is 2. timbre (TAM-ber)- the complexity of a sound Variations, flute vs. piano 3. intensity- the loudness of a sound 4. decibels- measures intensity

Touch- cutaneous senses We have 3 types of nerve receptors in our skin that each send messages into the brain

Touch- cutaneous senses 1. pressure- bruise, bug crawling, pinprick 2. temperature- registers changes in temperature of your surroundings 3. pain- Remains active continuously to record injuries or poison Will continue to send pain messages to brain until injury is gone

Smell Most animal like sense Olfactory bulbs- carry messages of smell to the brain When odors are associated with an emotion or event, we never forget If we smell the odor again the memories come back Sense of smell is connected to the limbic system Hippocampus forms memories Amygdala controls emotional response

Taste Taste receptors- chemical receptors on the tongue, decode molecules of food or drink to identify them Salty Sweet Sour Bitter Umami (new research)

Sensation Stations Meet with your group to work on the worksheet for your station You will need: To include a name for your station at the top (related to your sense) To print copes and have them here the start of the hour Wednesday (35 students- minus your group) To make sure the worksheet requires students write/answer/fill out something for both activities at your station To make sure the worksheet has instructions and will be self-explanatory for students at your station