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• • • • • Sensation overview Hearing (audition) Vision Chemical Senses Somatic Senses Announcement s
• Participation Poll: Midsemester course feedback • Do Subject Pool hours (& written Assignment 4) • Study Chs. 4 & 5 • Last day to drop course: Fri Oct 15th • Midterm Qs review in office hours starting Question
• Correlations between the IQ scores of identical twins reared together are higher than the correlations between IQ scores of identical twins reared apart. This finding suggests that __________ influences IQ scores.
a) b) c) d) genes environment gender date of birth Question
• Which of the following typically makes the experimental group and the control group very similar before the independent variable is manipulated by the experimenter?
a) b) c) d) Random sampling Random assignment Counterbalancing The double-blind design Answer
• Choice b is correct. • Random assignment tends to spread the effects of uncontrolled variables randomly across the groups in an experiment. (Chapter 2, Experiments: Exploring Cause and Effect section) • Sense: System that translates outside information into neural activity • Sensations: Messages from senses that provide a link to the environment • Perception: Making sensations into meaningful experiences Sensation L.O. 2 • Energy from the outside world psychological experience (perception) Sensation L.O. 2 • Accessory structures: Help collect energy from world
•e.g. lens in our eye focuses light Sensation L.O. 2 • Accessory structure: Helps collect energy from world • Sensory receptors: convert energy into action potentials (transduction) Sensation L.O. 2 • Accessory structure: Helps collect energy from world • Sensory receptors: convert energy into action potentials (transduction) • Sensory nerves: Carry info. to brain Sensation L.O. 2 • Accessory structure: Helps collect energy from world • Sensory receptors: convert energy into action potentials (transduction) • Sensory nerves: Carry info. to brain • Thalamus: “Relay station” in brain Sensation L.O. 2 • Accessory structure: Helps collect energy from world • Sensory receptors: convert energy into action potentials (transduction) • Sensory nerves: Carry info. to brain • Thalamus: “Relay station” in brain • Cerebral cortex (perception) Have you heard ringing in your ears after exercising? Have you seen stars after Getting hit in the head? Why Aren't Senses Always Accurate?
• Doctrine of specific nerve energies: Anything that stimulates sensory nerve produces sensation – There is only 1 specific way our brain interprets these – Can create illusions if it is stimulated for the “wrong” reason • 1: Exercising increases your blood pressure and causes your blood vessels to press on your auditory nerve. • 2: Your brain automatically interprets this activity as a sound. L.O. 5 1: This is because the visual cortex was activated by hitting the side of your skull. 2: Your brain interprets this as seeing something Hearing Hearing SOUND Physical Characteristics of Sound Sound
• Sound= vibrations. fluctuations in pressure. Physical Characteristics of Sound Sound
• Amplitude: Signal strength, base to peak • Wavelength: Distance between peaks • Frequency: Cycles/sec. 1 Hz = 1 cycle/sec AMPLITUDE Physical Property LOUDNESS Psychological Experience AMPLITUDE FREQUENCY / WAVELENGTH Physical Property LOUDNESS PITCH Psychological Experience • Pitch: High or low sound (in Hz)
– Higher frequency = higher pitch AMPLITUDE FREQUENCY / WAVELENGTH EXTRA WAVES Physical Property LOUDNESS PITCH TIMBRE Psychological Experience • Timbre: “Quality” of the sound
– Why the same note sounds different on 2 different instruments Five Steps in Hearing Five Accessory Structures modify sound: Pinna, external ear canal, tympanic membrane, hammer, anvil, stirrup Modifying Sound Modifying
Hits tympanic membrane Sound waves collected by Pinna Vibrations amplified by ear bones Oval window transfers sound to Cochlea Conduction deafness: Middle ear bones fused Five Steps in Hearing Five Sound is converted into a neuronal signal: Hair cells! (Transduction) Transduction of Sound Transduction
This causes the basilar membrane to bend Basilar membrane: Bendable floor of the cochlea Cochlea: fluid filled tube wrapped into a spiral Sound waves pass from the oval window through the fluid in the cochlea Movement of the basilar membrane moves the hair cells Organ of Corti: Hair cells touching the basilar membrane Hair cells are connected to the auditory nerve Auditory nerve: bundle of axons going to the brain Video 1 Video 2 Hair Cells
• Humans have ~15,500 hair cells • *** this is VERY low for a sensory cell *** • You are born with all the hair cells you will ever have • its all downhill from there Normal organ of Corti Traumatized organ of Corti Concept check Concept
My neighbor’s dog Buddy likes to bark at squirrels. When he does so the pressure from the sound eventually stimulates hair cells resting against my ______ A. inner ear B. Malleus C. Oval window D. Basilar membrane Five Steps in Hearing Auditory nerves carry output from Sensory receptors to CNS Five Steps in Hearing Neural energy travels to the thalamus: Primary processing occurs Five Steps in Hearing Sound information gets relayed to the auditory cortex: Perception Occurs Auditory Cortex
• Various aspects processed independently: source & frequency of sound
– Localizing sound: Detect time difference between 2 ears
• louder = closer The Problem of Coding
• Coding: How do the neurons form a representation of some physical stimuli?? Frequency Coding
• Place Theory: • Frequency Matching Theory: – Spatial code for frequency – http://www.blackwellpublishing.com/matthews/e – Certain frequencies activate areas of auditory cortex – Doesn’t hold up for very low frequencies – Temporal code – 1 fire per wave – Limited to 1,000 Hz – Volley Theory – neurons team up In Summary
Energy - sound - pressure fluctuations of air produced by vibrations Accessory structures - ear (pinna, tympanic membrane malleus, incus, stapes, oval window, basilar membrane) Transduction - hair cells of the organ of Corti Pathways and representations - auditory nerve to thalamus to primary auditory cortex ...
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This note was uploaded on 01/27/2011 for the course PSYCH 100 taught by Professor Grison during the Fall '07 term at University of Illinois at Urbana–Champaign.
- Fall '07