Chapter 5 Notes - Sensation & Perception

CHAPTER 5 sensation + perception Sensory Systems - responsible for prouding information about our surroundings which allow us to successfully novigate + inieract wul our entronments Sensation sensory receptors: specialized neurons that respond to specific types of stimuli sensation: occurs when sensory receptors detect sensory stimuli. when sensory receptors delect a specific, Stimuli, they conuent that energy into an acton potential whichis sent to central nervous system (called transduction) Senson Systems: vision • balance (vestibular sense) hearing (audition) • body position (proprioception) • Smen (olfocation) • movement (Kinesthesia) • taste (gustation) pain (nociception) • touch (somatosensation) • temperature (ther moception) - for astimuus to cause an action potential, it first has to be strong enough to be detectea Absolute Threshold: minimum amount of stimulus energy that must be present for tve stimulus to be detected 50% of time → sublimmal messages: ability to recelve messages presenied below the threshold of conscious awareness (can cause an action polental but we arc not consciousty aware of 1+) Just Noticeable Difference: tue minimum difference in stimuli required to detect a change or a difference between Stimull Lcan change depending on stimulus intensiry if things change slowly, we wont notice Perception - how we mierpret the information the sensory receptors collect + it affects now we interact wi wond Perception: way that sensory information is intenoreted, organized + Consclously experienced • 2 forms of processing... Bottom up processing: system in uhen perceptions are built from sensory input Top-Down processing: interpretation of sensations is infivanced by avallade knowicage, experence + #nougnis Factors Affecting Perception 1. senson adaptation: not porcelving stimull that remain relatively constant over prolonged pensas of time 2. Attention: •Inatientional blindness- failure to notice something that is complerely visible be of a lack of attention 3. Motivation: sometimes we thnk we hear something when it is not there be we are motivated to perceive 1+ signal detecton trean: change in sumous detection as a function of current mental stare 4. Beliets, valves, prejudices + expectations: 5. life cultural experiences VIsion our eyes take in sensory mformation that helps us understand the wond arand us Ampiltude + Wavelength •visual + auditory stimuli both our in tue form of waves • 2 physical proporties of waves: amplitude + waverengtn Ampitude or height of a waue is measured from peak to the trougn • wavelength is measured from peak to pear Light waves • tue visible spectrum is the portion of tue electromagnete spectrum that we can see • different specios can see different portions of me spectrum • humans can see wawelengths nanging from 380-740mm Percepton of color wavelength + Color • different wanelengins of light are associated wai our perception of different colors • longer wauerangins= reds intermadiale wavelengins- greens • Shorter waue engths: blues + violets Amplitude+ cor or "tue amplitude of lign waves is associated with brightness/ intensity of color • larger amplitudes appearbrighter Anatomy of Visual System I. light waves are transmitted across cornea + enter through the pupil pupil's size is controlled by muscles connected to the iris 2. light crosses the lens + Is focused on tue fovea (part of remina) → fovea contains photoreceptors 3. photoreceptors are connected to retinal ganglion cals. axons from these cells exit through tue back of the eye where they form the opte nerve 4. the optic nerve tuen carries tue visual information to the brain Blind spot: a pant of no receptors, where information exits the eye, where we cannot respond to visual information photoreceptors cones phototopic (daytimes vision Lawork best in bright light condition - hign -acuity color information • located in fovea Rods scotopic (high+time) vision La works best in low lignt conditions • high sensitivity • allows for low-acuity vision in dim lign+ • involved in tue percepton of movement in ourperpneral vision • located in the periphery of the retina Optic chiasm • tue optic nerve of cach eye merges @ the optic chiasm, an x-snaped store just-below tue cereral contex - information from the right visual field is sent to left hemisphere + info from left visual fied Is sent to right hemisphere - this information is tuan sent to occipital lobe for processing Visual Pathways after being processed in the occipital lobe, visual mformation exists * goes through 2 different patnways The "What" pathway: object recognition + identification tue "where/how" pathway: location in space + how one might interact wi a particular visual stimuus