Unit Two: Chapter Four

Sensation and Perception

Warm up 02/17

● How do your senses (sight, hearing, smelling, etc.) influence your behavior and mental processes?

The Basics

● Absolute Threshold○ weakest amount of stimulus that can be

sensed○ dog’s absolute threshold for hearing is lower

than humans○ App that only young people can hear○ differs from person to person

The Basics

● Differences in Threshold○ minimum difference between 2 stimuli

● Signal Detection Theory○ distinguishing sensory info

■ setting■ your physical state■ your mood■ your attitudes

○ focus on what you consider important○ different people find different things

important

The Basics

● Sensory Adaptation○ sense change to adapt to an environment○ more sensitive to weak stimuli & less

sensitive to unchanging stimuli■ eyes adjusting to the dark■ People in cities adjusting to sound of traffic

Vision

● Light ○ wavelengths - not all visible to humans

Vision

● The Eye○ light enters the eye and then is projected onto

a surface○ pupil - determines the amount of light that is

let in■ sensitive to light and emotions

○ lens - adjusts to keep objects in focus○ retina - consists of neurons

■ photoceptors - sends visual input to the brain

Vision

● blind spot - places in the eye that lack photoceptors

● rods and cones - types of photoceptors○ rods- brightness of light○ cones - color vision

● Visual Acuity ○ sharpness of vision

Vision

● Color Vision○ color circle - complementary colors○ afterimages - you perceive the afterimage of

a color once you view it for a while■ complementary pair

Vision

● Color Blindness○ not normal color vision○ unable to distinguish colors○ missing or malfunctioning cones○ total color blindness is rare

Activity

● Create your own color wheel. There is also an example in the book. ○ complementary colors are across from one

another

● Create your own afterimage.○ Remember the afterimage includes the

complementary color.

Chapter 4 Vocabulary

● sensation● perception● absolute threshold● difference threshold● signal-detection theory● sensory adaptation● pupil● lens● retina● gate theory● vestibular sense● similarity● continuity● stroboscopic motion

● photoreceptors● blind spot● visual activity● afterimage● cochlea● auditory nerve● conductive deafness● sensorineural deafness● olfactory nerve● kinesthesis● closure● proximity● monocular cues● binocular cues● retinal disparity

Warm Up 10/10

● When was the last time you had a vision test?

● Do you require glasses or contacts?

READ! ~10 minutes

Warm Up 02/18

● Do you rely more on your hearing or your sight?

● Why?

Hearing

● Pitch○ how high or low a sound is○ depends on the # of cycles per second○ we can hear things between 20 and 20,000

cycles per second

● Loudness○ depends on the height (amplitude) of sound

waves

Hearing

● The Ear○ outer, middle, and inner ear○ eardrum separates outer and middle ear

■ vibration transmits sound to the hammer, the anvil, and the stirrup

○ cochlea - converts vibrations into neural impulses that are transmitted to the brain

Hearing

● Deafness○ conducive deafness

■ damage to middle ear■ prevents people from hearing quieter sounds■ hearing aids can help

○ senisorineural deafness■ unable to perceive sounds of certain

frequencies■ neurons in cochlea are destroyed■ disease or prolonged exposure to loud sounds

● ipod deafness is real!

Hearing

● Deafness○ deafness in the world today

■ American Sign Language taught in schools■ “closed captioning”■ research on repairing ear damage

Warm Up 02/19

● Have you ever had a food craving? ● What food?

Other Senses

● Smell○ closely connected to taste○ receptor neurons deep in each nostril○ sends info through the olfactory nerve○ adapt to scents quickly

Other Senses

● Taste○ primary - sweet, sour, salty, and bitter○ umami - “savory”○ receptor neurons on taste buds on tongue

■ you can have low sensitivity to certain tastes

○ taste cells can re grow in a week

Other Senses

● Skin Senses○ pressure

■ sensory receptors in root of hair cells■ different parts of body more sensitive to

pressure than others○ temperature

■ neurons just beneath the skin■ different receptors for warmth and cool

Other Senses

● Skin Senses○ pain

■ pain receptors send message to spinal cord and thalamus

■ pain chemical = prostaglandin■ Gate theory = brain can only process so

many messages at a time● if you rub a sore spot on the body it distracts brain

from pain

■ phantom limb pains in amputees● neural impulse in stump left by missing limb

Other Senses

● Body Senses○ Vestibular

■ tells you if you are standing upright without using eyes

■ keep balance○ Kinesthesis

■ position and motion of the body■ info comes from joints, tendons, and

muscles

Grab a partner

● First, one of you demonstrate a complex set of movements○ dance, sports, yoga

● Second, the other member of the pair repeat the movement back.○ write down what the movement was and if it

was easy or difficult

● Switch Roles and repeat

Sensation Walks

● You’ll need to create something to block out your vision for our sensation walks…

● I have paper in the front.

Activity

● Smell/Taste Log○ write down over the course of today

everything you smell or taste○ was there a pattern?

Warm up 02/20

● What is perception?● How could it be different from a

sensation?

Perception

● Perceptual Organization○ closure

■ Gestalt psychology■ perceive object with gaps as whole

○ figure-ground perception■ figures against a background

○ other■ proximity (nearness)■ similarity (similar objects belong together)■ continuity (continuous patterns)

Perception

● Movement○ is hard to discern with only your eyes

● Stroboscopic Motion○ rapid progression of images - looks like

motion

Perception

➔ Depth Perception◆ monocular cues

● only need one eye to perceive them● some objects seem more distant

◆ binocular cues● both eyes required to perceive● retinal disparity

monocular cues

Perception

➔ Perceptual Constancies◆ size constancy

● you maintain the ability to distinguish the size of something no matter what distance away it is

◆ color constancy● things keep their color even in different

lighting◆ shape constancy

● same shape no matter the angle you view it

Perception

➔ Visual Illusions◆ Muller-Lyer illusion◆ Ponzo illusion

● example

Other Visual Illusions

other Visual illusions

Create your own Visual Illusions

● It can be a recreation of one we’ve talked about...or you can create something completely original