Audition (Hearing) - PDF

Audition (Hearing) We hear via sound waves Amplitude (height) of wave = loudness Loud sounds have high amplitudes Softer sounds have low amplitudes  Pitch – a tone’s experienced highness or lowness, depends on frequency Frequency – number of wavelengths that pass a point in a period of time...

Audition (Hearing) We hear via sound waves Amplitude (height) of wave = loudness Loud sounds have high amplitudes Softer sounds have low amplitudes  Pitch – a tone’s experienced highness or lowness, depends on frequency Frequency – number of wavelengths that pass a point in a period of time Low pitch/frequency sounds = bass High pitch/frequency sounds = high ringing  Outer Ear Pinna: external part of ear. Catches sound waves. Ear canal: channels sound waves to the middle ear.  Middle Ear Eardrum (Tympanic Membrane): thin membrane that vibrates when sound waves hit it. Can be ruptured when exposed to high levels of pressure or loud sounds/blasts. Ossicle Bones: (hammer, anvil, & stirrup) pick up vibrations and transmit them to the inner ear.  Conduction Hearing Loss Caused by damage to the structures that conduct sound waves through the outer and middle ear. Damage to eardrum Damage to ossicle bones Damage to auditory canal  Inner Ear Cochlea: spiral, fluid-filled tube that produces nerve impulses in response to sound vibrations. Oval window: the cochlea’s membrane covered opening.  Inner Ear Basilar Membrane: the inner lining of the cochlea where hair cells are located. Hair Cells (Cilia): Sensory receptors that bend in response to sound vibrations. Trigger impulses in the auditory nerve.  Inner Ear Hair Cells (Cilia): Can be permanently damaged by prolonged exposure to loud noise. Ringing in your ears is a sign that your hair cells are stressed/injured.  Tinnitus A chronic ringing in the ears. Caused by damage to and loss of the tiny sensory hair cells in the cochlea Tends to happen as people age. Can also result from prolonged exposure to excessively loud noise.  Auditory Nerve Sends neural impulses from the cochlea to the temporal lobe for processing.  Sensorineural Hearing Loss (Nerve deafness) Caused by damage to the cochlea’s hair cells or to the auditory nerve. CANNOT BE REVERSED.  Cochlear Implant ▪ Attached to side of the head and wired into the cochlea. ▪ Translates sounds into electrical signals that travel up the auditory nerve to the brain. Loudness: We detect loudness based on the number of hair cells that are activated. ▪ The louder the sound, the greater the number of activated hair cells. Frequency: The number of complete wavelengths that pass a point in a given time. ▪ Determines pitch (a tone’s highness or lowness). ▪ Long waves= low frequency/pitch ▪ Short waves = high frequency/pitch Place Theory: Says that higher and lower tones excite specific areas of the cochlea’s basilar membrane. We process pitch based on which part of the cochlea responds to incoming sound waves. ▪ The front of the cochlea responds to higher pitches ▪ The deeper areas of the cochlea respond to lower pitches Frequency Theory: Says that the brain detects pitch by monitoring the frequency of neural impulses traveling up the auditory nerve. ▪ The basilar membrane vibrates with the incoming sound wave ▪ This triggers neural impulses at the same rate as the sound wave’s frequency ▪ If the sound wave has a frequency of 100 waves per second, then 100 pulses per second travel up the auditory nerve. Frequency Theory: PROBLEM: A neuron cannot fire faster than 1000 times per second, so how can we sense sounds with frequencies above 1000 waves per second? Volley Principle: various neurons can alternate firing. By firing in rapid succession, they can achieve a combined frequency above 1000 waves per second. ▪ Think of it like soldiers who alternate firing so that some can shoot while others reload.  The two theories work together to enable our perception of pitch. Place theory best explains how we sense high pitches. Frequency theory best explains how we sense low pitches.  Locating Sounds The placement of our ears allows us to have stereophonic (multidirectional) hearing. A sound to your right hits our right ear more intensely and receives sound slightly sooner than your left ear.  Vestibular Sense Monitors the head’s position and movement so the body knows its position in space.  Vestibular Sense Fluid in the semicircular canals and vestibular sacs of the cochlea moves when your head rotates or tilts.  Vestibular Sense Hair-like receptors send signals to the cerebellum for processing.  Vestibular Sense The fluid takes time to settle, so your brain still thinks you’re moving even after you stop. This causes dizziness.  Our eyes detect light waves and transduce them into electrical impulses our Humans brain cancan only see a understand. small portion of the electromagn etic Wavelength: the distance from one wave peak to the next. Wavelengt h determines Amplitude: the wave’s height. Amplitude determines brightness (intensity)  Cornea Clear, protective outer layer where light enters the eye.  Iris Colored muscle that surrounds the pupil and controls its size. Each iris is so distinct that an  Pupil A small, adjustable opening that allows light to pass through.  Lens Transparent structure behind the pupil that changes shape to help focus images on the retina. Accommodatio n: The process by which the lens  Retina Light-sensitive inner surface of the eye. Photoreceptors called rods and cones detect light. This is where transduction  Receptors in the CON retina that detect color and fine ES ▪ Clustered in the fovea, a small depression in the detail. center of the retina Fovea is where acuity (sharpness) is strongest (This is why we see best when we look at something straight-on)  Receptors in the ROD retina that enable black and white and peripheral (side) S Located primarilyvision. in the outer regions of the retina. Allow you to see in dim light Can detect faint light Can detect peripheral  Adaptation to Dark In darkness, the pupils dilate to allow more light to reach the retina. Dark adaptation takes about 20 minutes (the average natural twilight transition Bipolar and Ganglion Cells Bipolar cells: connect rods and cones to ganglion cells. Ganglion cells: their axons make up the optic nerve which carries neural impulses to the brain for processing.  Rods and cones Bipolar Cells Ganglion Cells  Optic Nerve The nerve that carries neural impulses from the eye to the brain.  Blind Spot The point at which the optic nerve leaves the eye, creating a “blind spot” You don’t notice because because your brain fills in the space no and allows you to see a  Optic Chiasm The point in the brain where the optic nerve fibers from each eye cross over  Thalamus The first stopping point for incoming sensory information other than smell. Routes sensory input Primary Visual Cortex Where visual input is first processed. Located in the occipital lobe. Main area for processing vision.  Feature Detectors Neurons in the visual cortex that respond to specific features of a stimulus, such as shape, angle, or movement.  Parallel Processing The processing of many aspects of a stimulus simultaneously. What we see is a result of our brain integrating all the aspects of the stimulus into a whole image. Color Motion  Trichromatic ▪ Theory The theory that the retina contains three different color receptors—red, green, and blue ▪ When stimulated in combination, they can produce the perception of any  Colorblindness ▪ The inability to see colors in a normal way ▪ Caused by impaired functioning of red and green cones (or very rarely blue cones) ▪ Since purple requires red and blue light, if someone has impaired red  Opponent Process Theory Our ability to perceive color is controlled by three types of cells with opposing colors: ▪ red-green ▪ yellow-blue ▪ white-black These cells can only detect the presence of one color at a time because the two colors oppose one another. ▪ You do not see greenish-red because the opponent cells can only detect one of these colors at a time. ▪ Think of them like switches. If the blue switch and the red switch are turned on, you will see purple.  Color Vision Both theories are accurate! Trichromatic explains how we detect color in the retina. Opponent process theory explains how those colors are actually processed in the brain.  Color Vision Color constancy: the tendency to perceive a familiar object as having the same color under different conditions of illumination ▪ You know an apple is red even in dim lighting, so you perceive it as red even if it’s more brown in the dim light.  Color Vision Relative Luminance: the amount of light an object reflects relative to its surroundings. Context affects color perception!  Gestalt An organized whole. Gestalt psychologists emphasized our tendency to integrate pieces of information into meaningful wholes.  Gestalt Consider a face: ▪ When you look at a friend’s face the resulting perception is not merely a sum of angles, curves, shapes, and lines that make up the face. Rather, you perceive the face as a whole. ▪ Your mind has implicitly grouped all the stimuli that make up that face  Gestalt Proximity: we tend to group close objects together during perception.  Gestalt Similarity: we tend to group like objects together during perception.  Gestalt Closure: when we look at a stimulus, we tend to see it as a closed shape rather than lines; we tend to fill in gaps.  Gestalt Continuity: we have a preference for perceiving stimuli that seem to follow one another as part of a continuing pattern. ▪ we are more likely to see continuous and smooth flowing lines rather than broken or jagged ones. This is because once our eyes begin to follow something,  Grouping The tendency to organize images into meaningful groups/forms. Proximity: we group nearby figures together. Continuity: we perceive smooth, continuous patterns rather than discontinuous ones. Closure: we fill in gaps to create a complete, whole object. Similarity: we tend to group similar objects together  Figure-Ground Form Perception The organization of the visual field into objects (figures) that stand out from their surroundings (ground).  Depth Perception Binocular cues: depth cues that depend on the use of both eyes. Because your eyes are about 2.5 inches apart, your retinas  Depth Perception Retinal disparity: by comparing images from the retinas in the two eyes, the brain computers distance. (Binocular cue) The greater the disparity  Depth Perception Convergence: The closer an object is to your face, the more your eyes have to move inward to see it.  Depth Perception Monocular Cues: depth cues that only require one eye. Used for further distances.  Depth Perception Linear Perspective: makes parallel lines appear to converge at a vanishing point in the distance. The closer the lines, the  Depth Perception Interposition: if one object partially blocks the view of another, we perceive it as closer.  Depth Perception Relative size: we perceive something as farther away if it looks smaller than an object in the foreground that we assume is similar in size.  Motion Perception When large and small objects move at the same speed, the large object appears to move more slowly. Motion parallax: objects that are closer appear to move faster than objects that are further away.  Motion Perception Stroboscopic movement: when the brain perceives a rapid series of slightly varying images as continuous movement.  Motion Perception Phi phenomenon: an illusion of movement when two or more adjacent lights blink on and off in quick succession. Perceptual Constancy Shape constancy: we perceive familiar objects as constant even while our retinas receive changing images of them. Perceptual Constancy Size constancy: we perceive objects as having a constant size, even while our distance from them varies.  Sensation and Perception Unit Overview 1. Basics: How do we sense stimuli in our environment and how does our brain make sense of it? 2. Vision: Anatomy of the eye, how our eyes detect light, how our brain makes sense of visual input 3. Hearing: Anatomy of the ear, how our ears detect sound, and how our brain makes sense of that input Bottom-up processing Your brain is not yet assigning meaning to what you sense, it is only taking in information. This image doesn’t have any meaning to us, but we can take in the shapes, colors, and other visible features. Top-dow n processi ng Brain applies what it knows and what it Stroop Effect Delayed reaction time when you must say the color of a word but not the name of a word. BLUE YELLOW PURPLE Top-down processing recognizes the word first which  When you take in sensory information, you are using bottom up processing. When you recognize or assign meaning to that sensory information, you are using top down processing.  Selective Attention Focusing your awareness on one particular task or stimulus. ▪ Our consciousness can only focus well on one thing at a time. By one estimate, your five senses take in 11,000,000 bits of information per second, of which you consciously process about 40.  Distracted Driving ▪ Around 28% of traffic accidents involve texting while driving. This number is increasing every year. ▪ 58% of teen car crashes involved driver distraction from passengers or phones immediately before ▪ Using a cell phone carries the same risk as drunk driving ▪ You are 23 times more likely to get in a car crash if you are texting while driving Cocktail Party Effect The ability to focus auditory attention on a particular voice or sound while filtering out others. ▪ In a crowded room, you can focus on the voice of a single person you are conversing with.  Inattentional Blindness Failing to see visible objects when our attention is directed elsewhere. Change Blindness - Cognitive Psychology Experiment - Take Part!! - YouTube ▪ Change Blindness: failing to notice changes in the environment because your attention is directed Transduction Conversion of sensory input into electrical impulses the brain can use to process information. ▪ Receive sensory stimulation through receptors (eyes, taste buds, etc.) ▪ Transform that stimulation into neural Psychophysics The study of the relationship between physical stimuli and the sensations and perceptions they produce. ▪ Studies the relationship between physical energy we can detect  Signal Detection Theory Predicts how and when we detect a faint stimulus amid background noise. ▪ Detection depends partly on a person’s experience, expectations, motivation, and alertness ▪ Signal detection theorists seek to understand why people respond  Difference threshold (just Thenoticeable minimum amount difference) something needs to change before a person notices the change 50% of the time. Weber’s Law States that, for an average person to perceive a difference, two stimuli must differ by a constant percentage, not a constant amount. ▪ If you add 1 ounce to a 10 ounce weight you will detect the difference. ▪ If you add 1 ounce to a 100 Sensory Adaptation When constantly exposed to an unchanging stimulus, we become less aware of it. ▪ Neurons fire less frequently when the stimulus doesn’t change. ▪ Only exception is with vision because eyes are Subliminal Below one’s conscious awareness. Priming When exposure to one stimulus influences the response to another stimulus. Happens subliminally. Priming Priming thirstyactivates people withunconscious the subliminal associations word “thirst” can, for a moment, make a thirst-quenching beverage ad more persuasive, but “subliminal messaging” does not have a powerful, enduring effect Perceptual Set Our tendency to perceive one thing and not another based on experience and expectations (top-down processing). Emotion What we are feeling affects our perceptions. ▪ Hearing sad music can predispose people to perceive a sad meaning in spoken homophonic words—mourning rather than morning, die rather than dye, pain rather than pane. ▪ When angry, people more often perceive neutral objects as guns. ▪ When mildly upset by subliminal Motivation Motivations can bias our interpretations of neutral stimuli. ▪ Desirable objects, such as a water bottle viewed by a thirsty person, seem closer than they really are. ▪ A to-be-climbed hill can seem steeper when we are carrying a heavy backpack and a walking destination further away when we feel tired. ▪ A softball appears bigger when you’re Context The situation in which something happens can affect our perception of it. ▪ When holding a gun, people become more likely to perceive another person as also holding a gun. ▪ “Eel is on the wagon” is likely perceived as “wheel is on the wagon” because of the expectations created by context. ▪ Our culture shapes our perceptions. Extrasensory Perception (ESP) Perception that occurs without sensory input. There is no scientific basis for this. ▪ Telepathy: mind-to-mind communication without any sensory output/input. ▪ Clairvoyance: perceiving events you didn’t actually witness (knowing where a body is buried or how