Ch 3 Lecture Outline Sensation and Perception What is sensation The activation of receptors in the various sense organs ears eyes nose skin taste buds nervous system o Sensory receptors specialized forms of neurons the cells that make up the o Transduction conversion of outside stimuli into a neural signal in the brain o Just noticeable difference JND the smallest difference between 2 stimuli that is detectable 50 percent of the time o Absolute threshold the smallest amount of energy needed for a person to consciously detect a stimulus 50 percent of the time it is percent What are subliminal stimuli and what affect can they have on us Stimuli that are below the level of conscious awareness Just strong enough to activate the sensory receptors but not strong enough for people to be consciously aware of them Does not work in advertising o Supraliminal stimuli able to be consciously aware of but due to the fact tht your attention is directed elsewhere you are not Above absolute threshold Example engrossed in a book yet someone is calling your name and after 6 times you say whhaaaa What is habituation and sensory adaptation How are they different Habituation the tendency of the brain to stop attending to constant unchanging information Sensory adaptation the tendency of sensory receptor cells to become less responsive to a stimulus that is unchanging o Microsaccades constant movement of the eyes Eyes What are the properties of light Both waves and particles o Brightness color saturation three aspects to our perception of light o BRIGHTNESS determind by the amplitude of the wave how high or how low the wave actually is The high the wave the brighter the light will be o COLOR is determined by the length of the wave Long wavelengths are found at the red end of the wavelength the portion that is humanly visible o SATURATION refers to the purity of the color people see mixing in black or gray would lessen the saturation What are the structures of the eye Retina final stop for light in the eye Three layers ganglion bipolar photoreceptors cells that respond to various light waves Photoreceptors Rods adapted for vision in dim light Cones adapted for color vision daytime vision and detailed vision require a lot of light Fovea vast majority of cones are in here Very precise very clear vision What are some visual disorders o Lens deficits Presbyopia develops as we age Decreased flexibility of the lens and therefore inability to focus on nearby objects Cataract the lens becomes cloudy o Eye shape deficits Myopia can focus well on nearby objects but difficulty with distant objects Eyeballs are elongated Hyperopia can focus well on distant objects but not so well on close objects Eyeballs are flattened o Glaucoma increased pressure in the eyeball which can lead to optic nerve damage and the loss of peripheral vision tunnel vision What is the blind spot in the eye How does the information from our eyes become images we understand and process What are the theories of color vision o Trichromatic theory theory of color vision that proposes three types of cones yellow red blue Afterimages when a visual sensation persists for a brief time even after the original stimulus is removed o Opponent process theory we perceive color not in terms of independent colors but in terms of a system of paired opposites Red vs Green Yellow vs blue White vs black What is color blindness and what are the different types Monochrome colorblindness a person s eyes either have no cones or have cones that are not working Red green colorblindness either the red or green cones are not working protonopia red cones Deuteranopia green cones Tritanopia lack of functioning blue cones Sex linked inheritance Ears What are sound waves and what are the properties of sound waves Vibrations of molecules in the air or another medium o Amplitude interpreted as volume how soft or loud a sound is o Wavelength interpreted as frequency of pitch high medium low o Purity Timbre a richness in the tone of the sound How do we measure sound waves o Hertz cycles of waves per second a measurement of frequency Humans have limited range between 20 Hz 20 000 Hz Greatest sensitivy 2000 4000 Hz o Decibels a unit of measure for loudness What are the various different structures in the ear o Outer Ear pinna auditory canal o Middle Ear stapes o Inner Ear cochlea basilar membrane organ of corti Cochlea What are the different theories of pitch Pitch corresponds to the frequency of the sound waves the higher the frequency the higher the pitch Taste umami Smell Somesthetic o Place theory the stimulation of hair cells in different locations in the organ of o Frequency theory related to the speed of vibrations in the basilar membrane o The basilar membrane vibrates unevelnly when the frequency is above 1000 Hz o Neurons associated with the hair cells fire as fast as the basilar membrane vibrates corti place theory up to 1000 Hz What are the two ways in which a person can be hearing impaired and how can we help people who are hearing impaired Conduction hearing impairment can result from damaged eardrum damaged stapes Nerve hearing impairment can result from damage in the inner ear damage in the auditory pathways What is gustation Taste buds Taste receptor cells in mouth What are taste buds Where are they located What are their properties and structures o Papillae tastes buds like the walls of these come in two different sizes Smaller and more numerous ones are touch sensitive and rough They help chew and move food Larger one contains the taste buds What are the basic tastes humans can experience Sweet sour salty bitter brothy or What is olfaction Sense of smell There are at least 1 000 olfactory receptors What are olfactory bulbs What are the somesthetic senses The body senses consisting of the skin senses the kinesthetic sense and the vestibular sense o Cutaneous senses skin senses pressure warmth cold pain vibration movement and stretch Some places receptors are densely packed fingertips and lips Sensory receptors Phantom limbs each other o Kinesthetic sense sense of the location of body parts in relation to the ground and o Vestibular sense the direction of tilt and amount of acceleration of the head and the position of the head with respect to gravity Plays a key role in posture and balance motion sickness Perception What is perception The method by which the sensations experienced at any given moment are interpreted by what you see What are some of the