PSYC 107 1nd Edition Lecture 16 Outline of Last Lecture I Sensation and Perception II Sensory Reality III Sensing the World Outline of Current Lecture I Vision Feature Detection Shape Detection II Color III Hearing Current Lecture I Vision How Light Enters the Eye Iris opening that modifies the amount of light permitted through the pupil The cornea and lens focuses light Cornea the transparent tissue that refracts light to focus on the back of the eye Lens changes curvature to refract light onto the back of the eye Shape of the eye affects how much the lends must bend light to focus it Retina contains sensory receptors that process visual information and sends it to the brain Changing light to neural activity Retina is a membrane at the back of the eye Fovea is the center of the retina and is responsible for acuity Receptor cells contain photopigments that change exposure to light Cones Rods These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute Number 6 million 120 million Location in Retina Center Periphery Sensitive in Dim Light Low High Color Sensitive Yes No Detail Sensitive Yes No The rods work more in low level light Cones work more in high color vision Ganglion cells their axons leave the retina at the blind spot forming the optic nerve which travels to the brain Bipolar cells receive messages from photoreceptors and transmit the message to the ganglion cells which then transpose them to a form the optic nerve can read You can test your blind spot in your textbook in Chapter 6 Optic nerves connect to the thalamus in the middle of the brain and the thalamus connects to the visual cortex Feature Detection Nerve cells in the visual cortex respond to specific features such as edges angles and movements Prosopagnosia is the inability to identify faces and recognize familiar faces Shape Detection Different parts of the temporal lobe work together to put together a world of shapes Different parts of the temporal lobe process different shapes Parallel processing allows us to see the world as we see it now parallel processing processes several aspects of one thing simultaneously Example when seeing a bird your brain processes its shape motion dorm and depth all at the same time II Color Trichromatic theory The theory that the eyes must contain three receptor cells that are each sensitive to either blue red or green III Color blindness is a genetic disorder where people are blind to greens or reds suggests trichromatic theory is correct The other theory is the opponent process theory which says that there are receptors that respond to pairs of colors white vs black red vs green and yellow vs blue Both theories are correct Hearing The stimulus input sound waves which are compressing and expanding air molecules Frequency pitch the dimension of frequency that is determined by the wavelength of the sound measured in hertz and humans can hear 20 20 000 Hz Intensity loudness the amount of energy in a wave determined by the amplitude measured in decibels 0db is the absolute threshold Wavelength the peak of one wave to the peak of the next Parts of the ear Outer ear collects and sends sounds to eardrum filled with air Middle ear filled with air chamber between eardrum and cochlea Contains tiny bones anvil hammer and stirrup called the ossicles Inner ear filled with liquid innermost part of the ear containing the cochlea semicircular canals and vestibular sacs Pitch perception different tones excite different parts of the basilar membrane and primary auditory cortex High tones 200 20 000 Hz Low tones 0 200 Hz Deafness vs Hard of Hearing Deafness causes Genetic Disease mumps measles Injury Exposure to loud noise Conductive deafness Malfunctioning of the ear Hearing aids amplify sounds Nerve deafness Damage to the hair cells or auditory nerve Cochlear implant bypasses the outer middle ear
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