Sensation • Sensory receptors detecting information and transmitting the information to the brain Perception • The process by which the brain organizes and interprets sensory input Sensation: Continual Process • Bottom-up processing: Analysis that begins with sensory receptors and works up to higher levels of processing • Sensory receptors take energy from the environment and transform it into other forms of energy Sensation: Continual Process • Top-down processing: Constructs perceptions from this sensory input by drawing on your experience and expectations • The way we interpret what we are sensing • Based on histories and experience Sensation: Transduction • Conversion of one form of energy into another • Receive • Sensory stimulation • Transform • Stimulation become neural impulses • Deliver • Neural information delivered to brain Sensation & Perception: Continual Process Absolute Threshold • Edge of awareness • The minimum stimulus energy (frequency) in which you could determine the sound 50% of the time • The point in which half the time you could detect the sound and and half the time you could not Signal Detection Theory • Detecting a weak stimulus depends not only on its strength but also our psychological state (e.g., experience, expectations, motivation, and alertness) • Predicts how and when we will detect weak signals amid background stimuli • “The music is too loud for me to see my turn” Subliminal Messages • Stimuli presented below the absolute threshold Difference Thresholds • Minimum stimulus difference a person can detect half the time • Barely difference between two stimuli, a person may not be able to discriminate between Sensory Adaptation • Diminished sensitivity as a consequence of constant stimulation • Become less aware of an unchanging stimulus because our nerve cells fire less frequently • E.g., Adjusting to someone’s perfume Exception: Eye Sight • Eyes are constantly moving and focusing on different stimuli • Allows us to focus on informative changes in our environment Theory of Perceptual Set • A mental predisposition to perceive one thing and not another • Our perceptions are influenced by learning histories and experiences Influences on Perception • Context • Where we live, what we are doing, what people are wearing • Motivation and Emotion • How we are feeling, what gives us energy, whether listening to happy or sad music • Sad music predispose us to a sad meaning • A hill seems steeper when we are carrying a heavy backpack Laura walks in to her room and immediately smells the fowl smells of her roommate's dirty laundry. But, after a while, Laura no longer smells the dirty laundry. This is an example of ____________ Ashley takes a walk around the beach. While she is walking her sensory organs are transforming everything she is sensing into different forms of energy. Is this an example of Perception OR Sensation? Ashley takes a walk around the beach. While she is walking she sees somethings swimming in the water. She thinks she sees a shark! Is this an example of Perception OR Sensation? LIGHT AND VISION How do our eyes SEE? • Eyes do not see objects as visual objects • Eyes receive light energy from different objects • Electromagnetic Energy • Energy that travels in waves at the speed of light Light Characteristics • Travels in waves • Wavelengths: The distance from the peak of one light or sound wave to the peak of the next • Two distinct characteristics help us see • Hue: The dimension of color is determined by wavelength of light • Intensity: The amount of energy in light waves The Eye: Seeing Process • Light enters the cornea • Light bends as it goes through the cornea • This helps the eye focus • Light then goes through our pupil • Pupil: The adjustable opening in the center of the eye through which light enters • The iris contracts to control the intensity of the light energy • Iris: Ring of muscle tissue that forms the colored portion of the eye around the pupil and controls the size of the pupil opening • Light energy goes through the lens • Lens: Transparent structure behind pupil that changes shape to help focus images of the retina • The energy gets projected to the retinas • Retina: Light-sensitive inner surface of the eye, containing receptor rods and cones and layers of neurons that begin processing visual information • The image is not projected onto our retina upside down • Receptor cells in our eye are responsible for turning the light energy into neural impulses, which get forwarded to the brain Cones & Rods • Cones • • • • Found in the fovea (retina’s area of central focus) of the eye Communicate directly to the brain Better at detecting details Help you see color • Rods • Enable black and white vision • Share cells that communicate to the brain 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 • Creates a blind spot because no receptor cells are located there Pathway to the Brain • Sensory information also goes to the occipital lobe • Where visual information is processed Psychologists and Eye Tracking Research • Some children with developmental disabilities display social skill deficits • May not attend to correct features • Dr. Josh Williams does some great innovative research with eyetracking and infants! What nerve carries neural impulses from our eyes to our brain? T/F. Images are projected onto our retinas upside down Cones helps us see __________ while Rods helps us see _____________ Color Processing Theories • Young-Helmholtz Trichromatic Theory (Three Color Theory) • Opponent-Process Theory Young-Helmholtz Trichromatic Theory • Our eyes have three types of color receptors • Green • Blue • Red • We see all other colors as a combination of any of the three primary colors • E.g., Red and Green cones are stimulated, we see blue Young-Helmholtz Trichromatic Theory • Most humans can detect over 1 million color variations • Criticisms • Why can some people see yellow when they can’t see blue and red Opponent Processing Theory • Theory that states we have three sets of opponent retinal processes • Red-Green • Yellow-Blue • White-Black • The different colors that we see are processed by the corresponding cells Feature Detection Our brains also have nerve cells that help us discriminate between different features Different parts of our brain help us detect faces, angles, etc.. Depth Perception • Ability to see objects in three dimensions although images that strike the retina are two-dimensional • Allows to judge distance Research on Depth Perception • Gibson & Walk (1960) • Evaluated whether visual depth perception is innate or learned • 27 babies • 3/27 crawled to the mother from the shallow end • 1/27 crawled to the mother from the visual cliff side Depth Perception • Binocular cues • Depth cues such as retinal disparity (how close something is to us) depends on the use of two eyes • By comparing images from the retinas in the two eyes, the brain understand distance, the greater the disparity, the closer the object • Monocular cues • Depth cues such as interposition and linear perspective, avaible to either eye alone Form Perception Relative luminance Hearing and Sound Audition • The sense or act of hearing • Sensory organs in ears help us detect sound waves Sound Waves • Brief air pressure changes • Vary in shape • Amplitude • Determines loudness • Frequency • The number of complete wavelengths that pass a point in a given time • Determines the pitch (highness or lowness) The Ear: Hearing • Sound waves travel to the eardrum in our middle ear • Middle Ear: The chamber between the eardrum and cochlea containing three tiny bones (hammer, anvil, and stirrup) • Those sound waves then get transmitted to cochlea • Inner Ear: The innermost part of the ear, containing the cochlea, semicircular canals, and vestibular sacs. • Cochlea: A coiled, bony, fluid-filled tube The Ear: Hearing • Vibrations are then triggered which cases fluid waves • Fluid waves trigger neural impulses Pain Pain • Nociceptors • Sensory receptors that enable the perception of pain in response to potentially harmful stimuli • Gate Control Theory • Spinal cord contains a neurological “gate” that blocks pain signals or allows them to pass on to the brain Learned Pain • Pain is also influenced by our environment and our learning history • We learn to feel pain (to a certain degree) • Chambers, Craig, & Bennett (2002) • Had mothers interact with their daughters in three ways while their child experience pain • Pain Promoting • Pain Reducing • No Interaction • Children that had Pain Promoting interaction reported more pain Pain Aggression • Early research in behavior analysis and pain discovered pain aggression • • Pain Aggression Aggression induced by painful stimuli • Blanchard & Blanchard (1977) • Put two rats in a chamber with a divider • Delivered shock to one rat and then opened the divider • Researchers found that rats would aggress towards each other after being shocked Tastes Taste • Chemical sense • Tastes help us survive and adapt • Tongue contains bumps that contain 200 or more taste buds • Each tase bud contains 50- 100 taste receptors Smell Smell • Chemical sense • Nasal cavities contain 20 million receptor cells for smells • Different smells trigger various receptors Smell • Olfactory cells are activated and send messages to Axon Fibers • Fibers send signal to our brain Sensory Interaction Principle • The principle that one sense may influence another, as when the smell of food influences its taste

Sensation and Perception: The Mind's Eye

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