Sensation and Perception - Chapter 5 PDF

Sensation and Perception - Chapter 5 shekinah jireh nueva Sensation is the physical process; perception is the psychological process Sensory receptors specialized neurons that respond to specific types of stimuli when sensory information is detected by a recept...

Sensation and Perception - Chapter 5 shekinah jireh nueva Sensation is the physical process; perception is the psychological process Sensory receptors specialized neurons that respond to specific types of stimuli when sensory information is detected by a receptor, sensation happens Transduction - conversion from sensory stimulus energy to action potential Vision Taste (gustation) Body position and movement (proprioception and kinesthesia) Hearing Touch Pain (nociception) (auditory) (somatosensation) Smell Balance (vestibular Temperature (thermoception) (olfactory) sense) Absolute threshold the minimum amount of stimulus energy present for the stimulus to be detected 50% of the time the sensitivity of a sensory system Subliminal messages messages presented below the threshold for conscious awareness “hidden messages/cues” Just noticeable difference (JND) or difference threshold required difference in stimuli to distinguish them example: ○ it’s easier to spot a bright screen in the dark than in daylight Perception how sensory information is organized, interpreted, and consciously experienced involves both bottom-up and top-down processing not all sensation result in perception Bottom-up processing perceptions are built from sensory input “you sense it then you react” Top-down processing the interpretation of sensations, influenced by our knowledge, experience, and thoughts “we already have prior knowledge; we now expect how things will happen” example: ○ avoiding dangerous situations Sensory adaptation no perception of stimuli that remain constant over time Attention an important factor in sensation and perception determines what is sensed and perceived Inattentional blindness ○ failure to notice something visible due to lack of attention Motivation an important factor in sensation Signal detection theory ○ identifying stimulus despite a busy/distracting environment Amplitude and Wavelengths Amplitude height of the wave measured from its peak (highest point) to trough (lowest point) Wavelength length between two peaks related to the frequency of the wave Frequency number of waves that pass at a period of time uses hertz (Hz) as the unit low frequency = long wavelengths high frequency = short wavelengths Light Waves Visible spectrum visible portion of the electromagnetic spectrum humans detect 400 to 700 nm (nanometers) Sound Waves the frequency of a sound wave associated with pitch humans detect 20 to 20,000 Hz high frequency = high pitch low frequency = low pitch Pitch differentiates shrill and flat sounds shrill sounds - high and sharp pitch flat sounds - low and soft pitch Loudness associated with the amplitude high amplitude = loud sounds low amplitude = soft sounds uses decibels (dB) as the unit Timbre affected by frequency, amplitude, and timing of the sound waves the tone quality/purity of the sound differentiates different sound production Anatomy of the Visual System Eyes - major sensory organ for vision Cornea - transparent covering/barrier of the eyes Pupil small opening where light passes size changes depending on the brightness and emotional arousal Iris controls the size of pupils  colored portion of the eyes Lens transparent structure that provides additional focus Retina light-sensitive lining of the eye Fovea ○ small indentation at the back of the eye ○ contains photoreceptor cells Cones - photoreceptors for bright light conditions Rods - photoreceptors for low light conditions Retinal ganglion cells where rods and cones are connected axons from these cells travel through the back of the eye to form the optic nerve optic nerves ○ carries visual information from retina to the brain Optic chiasm x-shaped structure sitting below the cerebral cortex information from the right and left visual field are switched ○ the visual information is then sent to the occipital lobe Visual blind spot (scotoma) caused by the lack of photoreceptor cells where the optic nerve and blood vessels leave the eye  part of the retina that does not provide visual information Color and Depth Perception Color vision Trichromatic theory of color vision ○ all colors in the spectrum are a combination of red, green, and blue Opponent-process theory ○ proposes that when one color is seen, its opponent color is registered once the stimulus is removed ○ color is coded in opponent pairs; black-white yellow-blue green-red ○ Afterimage the continuation of visual sensation even after removing the stimulus Depth Perception the ability to see objects in three-dimensional space (3-D) Binocular cues seeing with both eyes binocular disparity ○ differences between visual angles Monocular cues provides depth information when only seeing through one eye linear perspective ○ creating an illusion of depth on a flat surface Anatomy of the auditory system Pinna outer ear extends from the ear, auditory canal, and eardrum (tympanic membrane) Ossicles three tiny bones in the middle ear malleus (hammer), incus (anvil), stapes (stirrup) Inner ear contains the semicircular canals ○ involved in balance and movement (vestibular sense) also contains the cochlea ○ fluid-filled, snail-shaped structure ○ contains sensory receptor cells (hair cells) for the auditory system Hair cells auditory receptor cells embedded in the basilar membrane ○ a thin strip of tissue inside the cochlea *sound waves travel through the canal and strike the eardrum, causing it to vibrate *as ossicles move, the stapes presses into the oval window of the cochlea *the fluid inside the cochlea moves, stimulating the hair cells *the hair cells generate neural impulses which are moved to the inferior colliculus, medial geniculate nucleus of the thalamus, and the auditory cortex of the temporal lobe Pitch Perception Temporal theory human perception of sounds depend on the temporal patterns  hair cells would send action potentials related to the frequency of the sound Place theory different portions of the basilar membrane are sensitive to the sounds of different frequencies base of the basilar membrane = high frequencies tip of the basilar membrane = low frequencies Sound Localization Monaural cues using one ear to locate sound the sound waves that both ears receive are different Binaural cues using two ears to locate sound along a horizontal axis the sound waves that both ears receive are identical interaural level difference ○ the sound on one side of the ear is more intense than the other interaural timing difference ○ difference in the time where the sound waves reach the each Hearing Loss Deafness partial or complete inability to hear congenital deafness - being born deaf conductive hearing loss - hearing loss over time due to; ○ age ○ genetic predisposition ○ environmental effects; exposure to extreme noise certain illnesses damage from toxins Sensorineural hearing loss hearing loss due to failure to transmit neural signals from cochlea to the brain Meniere’s disease ○ degeneration of inner ear structures, leading to; tinnitus (constant ringing/buzzing) vertigo (dizziness) increased pressure in the inner ear  ○ cochlear implants - treatment for this disease The Chemical Senses Taste (Gustation) Taste groups; ○ sweet ○ salty ○ sour ○ bitter ○ umami - “yummy”; taste for monosodium glutamate Taste buds ○ groups of taste receptor cells with hair-like extensions that extends to the central pore of the buds ○ taste information is transported to the; medulla thalamus limbic system gustatory cortex Smell (Olfaction) Olfactory receptor cells ○ located in a mucous membrane at the top of the nose ○ the small hair-like structures of these receptors are sites for odor molecules ○ once an odor molecule has bound a receptor, chemical changes within the cell forms signals sent to the olfactory bulb ○ olfactory bulb - at the tip of the frontal lobe where olfactory nerves begin ○ from the olfactory bulb, information is then sent to; regions of the limbic system the primary olfactory cortex, near the gustatory cortex  Pheromones ○ chemical messages sent by another individual ○ often involves providing information about the reproductive status of a potential mate Touch, Thermoception and Nociception Receptors throughout the skin; Meissner’s corpuscles - respond to pressure and lower frequency vibrations Pacinian corpuscles - detect temporary pressure and higher frequency vibrations Merkel’s disks - respond to light pressure Ruffini corpuscles - detect stretch *nerve endings respond to different touch-related stimuli and serve as receptors for thermoception (temperature perception) and nociception (sensory for pain) Pain Perception Pain - unpleasant experience, physically and psychologically inflammatory pain - signals tissue damage neuropathic pain - damage to neurons of either the peripheral or central nervous system Congenital analgesia ○ genetic disorder where one is born without the ability to feel pain ○ can detect temperature and pressure, but not pain The Vestibular Sense, Proprioception, and Kinesthesia Vestibular sense ability to main balance and body posture main sensory organs; ○ Utricle ○ Saccule ○ the three semicircular canals ○ the vestibular organs fluid-filled and have hair cells respond to head movements and gravitational forces Proprioception perception of body position interact with information provided by the vestibular system Kinesthesia perception of the body’s movements interact with information provided by the vestibular system Gestalt Principles of Perception Gestalt - forms or patterns *the brain creates a perception that is the sum of available sensory inputs Gestalt Principles Figure-ground relationship ○ we segment our visual world into figure and ground ○ figure - object of focus ○ ground - the background ○ our ability to interpret sensory information depends on what we label as figures and grounds Proximity - things that are closer tend to grouped together Similarity - things that are alike tend to be grouped together Law of continuity (good continuation) - we perceive continuous, smooth flowing lines more than jagged, broken lines Closure - we organize our perceptions into complete objects rather than a series of parts Pattern perception ability to separate different figures and shapes occurs by following the mentioned principles Perceptual hypothesis educated guesses while interpreting sensory information