SENSORY AND PERCEPTION • The Sensory System - is comprised of receptors, signals, and parts of the brain that detect and interpret environmental signals. - a part of the nervous system consisting of sensory receptors that receive stimuli from the internal and external environment, neural pathways that conduct this information to the brain and parts of the brain that processes this information. • Sensory - Sensory information includes things you see, hear, smell, taste, or touch. - Sensory processing disorder can affect all of your senses, or just one. SPD usually means you're overly sensitive to stimuli that other people are not. - The process by which our sensory reception and nervous system receive and represent stimulus energies from our environment • Perception - the process of organizing and interpreting sensory information, enabling us to recognize meaningful objects and events. - the process or result of becoming aware of objects, relationships, and events by means of the senses, which includes such activities as recognizing, observing, and discriminating. - In psychology, sensation and perception are stages of processing the sensory systems, such as vision, auditory, and pain sensory systems. • Transduction - information gathered from your sensory organs is converted into neural impulses that are carried through the peripheral nervous system to your brain. - refers to changing physical energy into electrical signals (neural impulses) that can make their way to the brain. - Example: your ears receive energy (sound waves) and transduce (or convert) this energy into neural messages that make their way to your brain and are processed as sounds. - In the eyes, light waves create neural impulses - In the nose, chemical reactions from gaseous molecules create neural impulses - On the tongue, chemical reactions create neural impulses - In the ear, sound waves create neural impulses - Within the skin, pressure, pain, and temperature create neural impulses. • Absolute Threshold - The minimum amount of stimulation required before a sensation is evoked. • Sensory Adaptation - The ability of the sense receptors to adjust to a particular stimulus - Example: if we go inside a movie house, we may not be able to see right away, but after a while, our eyes become adapted to the darkness - a reduction in sensitivity to a stimulus after constant exposure to it - While sensory adaptation reduces our awareness of a stimulus, it helps free up our attention and resources to attend to other stimuli in our environment. • Bottom-up processing - what am I seeing? - Taking information and then assembling and integrating it - when sensory receptors pick up signals for the brain to integrate and process - An example of this is stubbing your toe on a chair, the pain receptors detect pain and send this information to the brain where it is processed. - How does bottom up processing work? 1. We experience sensory information about the world around us, such as light levels from our environment 2. These signals are brought to the retina. Transduction transforms these signals into electrical impulses that can then be transmitted 3. Electrical impulses travel along visual pathways to the brain, where they enter the visual cortex and are processed to form our visual experience. • Prosopagnosia - also known as face blindness, is a neurological disorder in which people are unable to recognize familiar faces, including their own. - While other aspects of visual processing and cognitive functioning remain unaffected, people experience functional sensation but incomplete perception • Top-down processing - perceptions begin with the most general and move toward the more specific. These perceptions are heavily influenced by our expectations and prior knowledge. Put simply, your brain applies what it knows to fill in the blanks and anticipate what's next. •Difference between bottom-up and top-down processing - So, bottom-up processing is data-driven, and your perception of what it is that you're looking at directs your cognitive awareness of the object. So, in contrast, top-down processing basically uses your background knowledge, so uses your background knowledge to influence perception. • Selective Attention - the focusing of conscious awareness on a particular stimulus - the processes that allow an individual to select and focus on particular input for further processing while simultaneously suppressing irrelevant or distracting information. • Cocktail-party effect - describes the ability to focus one’s listening attention to a single talker among a mixture of conversations and background noises, ignoring other conversations. - Driven to Distraction: In driving-simulation experiments, people whose attention is diverted by cellphone make more driving errors. • Selective inattention - unmindful absence or failure of attention to particular physical or emotional stimuli. - a perceptual defense in which anxiety-provoking or threatening experiences are ignored or forgotten. • Change Blindness - failing to notice changes in the environment • Parts of the Eye - Pupil: adjustable opening in the center of the eye through which light enters. - Iris: a ring of muscle tissue that forms the colored portion o the eye around the pupil and controls the size of the pupil - Lens: the transparent structure behind the pupil that changes shape to help focus images on the retina - Retina: the light-sensitive inner surface of the eye on which images are formed and contains the rods and cons - Rods: receptors that make us see during night time - Cons: receptors for color; these are the ones that make us see during day time • Process 1. 2. 3. 4. 5. Light entered through the lens before reaching the retina Photo receptors are then encountered (rods and cons) Optic nerve to brain’s visual cortex Information is processed, filtered, interpreted, compared with existing patterns Information is reassembled into a complete picture • Common Visual Defects • 1. Astigmatism - caused by incorrect curvature of the cornea, the cornea is slightly oval in shape instead of being spherical. - People who have astigmatism have imprecise near and far vision; their peripheral vision is unclear and they cannot clearly distinguish certain shapes and details or see contrasts clearly between horizontal, vertical, or oblique lines. - May be combined with other eyesight problems such as myopia, hyperopia, or presbyopia 2. Colorblindness - may be partial or total colorblindness - A partial colorblind has lost his vision for red, green, or blue color - To a totally color-blind, all colors are simply shades of black and white 3. Myopia (nearsightedness) - is a visual defect mainly cause by the eye being too long, meaning the distance between the cornea and the retina is too great. - The more a person is nearsighted, the more he/she must approach an object to see it clearly. 4. Hyperopia (farsightedness) - is mainly caused by the eye being too short, meaning the distance between the cornea and the retina is not great enough. - In such cases, the image forms just behind the retina, which explains why hype ropes see thing better far away than close up. •Hearing • Structure of the Ear - Outer (External) Ear: composed of the pinna, auditory canal and the eardrum. Involved with hearing - Middle ear: composed of three tiny bones: hammer, anvil, and stirrups. Involved with hearing - Inner ear: composed of the vestibular portion and cochlea, key to both hearing and maintaining equilibrium - Pinna or Auricle: catches sound waves, and passes them along deeper into the ear - External acoustic meatus: auditory canal - Tympanic membrane (eardrum): a thin flap of skin that is stretched tight like a drum and vibrates when sound hits it. These vibrations move the tiny bones of the middle ear, which send vibrations to the inner ear. - Tympanic cavity: amplifies sound waves so they’re stronger when they enter the inner ear - Basilar membrane: the vibration of the basilar membrane leads to stimulation of the hair cells– the auditory receptors of the organ of corti, important for understanding sound - Organ of corti: receptors for sense of hearing •Process 1. Pinna collects sound from the surroundings 2. Eardrum vibrates with sound waves 3. Vibrations are amplified by the hammer, anvil, and stirrup 4. The cochlea converts amplified vibrations into electrical signals 5. Auditory nerve transfers electrical signals to brain and the brain interprets it as a sound • Fun fact 😸 - Of the 206 bones in the human body, the six smallest are in your ears: three in the right and three in the left. Together, each three are about the size of a pencil eraser - Thunder is the sound accompanied by lightning, but often there is a delay between when we see lightning and hear the thunder. That’s because sound travels nearly 760mph whereas light travels about 186,000 mph. This is why we see lightning before we hear thunder. • Amplitude - size of the vibration, and this determines how loud the sound is • Frequency - the speed of the vibration, and this determines the pitch sound •Sense of Smell: Olfactory sensation - fragrant (e.g. florals and perfumes) - Fruity (all non-citrus fruits) Citrus (e.g. lemon, lime, orange) Woody and resinous (e.g. pine or fresh cut grass) Chemical (e.g. ammonia, bleach) Sweet (e.g. chocolate, vanilla, caramel) Minty and peppermint (e.g. eucalyptus and camphor) Toasted and nutty (e.g. popcorn, peanut butter, almonds) Pungent (e.g. blue cheese, cigar smoke) Decayed (e.g. rotting meat, sour milk) •Sense of Taste: Gustatory Sensation Tastebuds- sense receptors for taste •Sense of Touch: Cutaneous Sensation The Skin -the largest organ of the body -The stimuli to which it is sensitive are the thermal pressures and temperature •Kinesthetic Senses - provide information about the movement, posture, and orientation •Vestibular Sense - provides information about the balance and movement - Example: You know whether you are falling or going up, rotating or standing still, going forward or backward. •Factors that Influence Perception •Stimulus Characteristics 1. Principle of figure and ground relationship 2. Principle of proximity 3. Principle of similarity 4. Principle of closure •Principle of Figure and Ground Relationship - when we see a stimulus, part of what we see is the center of our focus, figure, and the remaining part becomes the background •Principle of Continuity - we perceive smooth, continuous patterns rather than discontinuous ones - This pattern could be a series of alternating semicircles, but we perceive it as two continuous lines- one way, one straight. •Principle of Proximity - objects that are close to each other are perceived as one - In our society where interpersonal relationship is highly valued, people who frequently go together are seen to be close to each other. •Principle of Similarity - we tend to perceive like or similar elements as belonging together - Thus, we tend to see columns instead of rows. •Principle of Closure - we tend to perceive incomplete forms as complete - According to Kellman, missing sensory information is automatically “filled in” in the process of perception to create complete whole perception. •Characteristics of the Perceiver 1. Motivation 2. Age 3. Gender 4. Economic status 5. Values 6. Past experiences 7. Frame of reference •Depth Perception - enable us to estimate an object’s distance from us - The ability to perceive objects three dimensionally. - •Different Cues in Depth Perception - Binocular Cues : depth cues that depend on the combination of the images in the left and right retina. : - Monocular Cues : depth cues such as interposition and linear perspective, available to either eye alone. : Ex. Linear perspective, texture gradient, and movement •Linear Perspective - Objects are farther away appear to be smaller and closer together •Speed of Movement - objects farther away appear to move across the field of vision more slowly than do closer objects. - For example, suppose a dog runs from a distance, it appears to move slowly but if it runs right in front of us, it appears to move quickly. • Perceptual Constancy - our perceptions of objects remain constant and stable regardless of its distance and position - Example: size constancy, shape constancy, and brightness constancy •Extra Sensory Perception (Psi Phenomenon)-perception without sensation - Mental telepathy– mind reading - Clairvoyance– the perception of external events without normal sensory stimulation - Precognition– ability to see future events before they happen - Psychokinesis– the ability of the mind to move objects without actually moving them.
