ITP Sensation And Perception PDF

ITP: SENSATION AND PERCEPTION regions have shown to specialize in processing particular tasks. SENSATION: input about the physical world obtained by our sensory receptors SYNESTHESIA:...

ITP: SENSATION AND PERCEPTION regions have shown to specialize in processing particular tasks. SENSATION: input about the physical world obtained by our sensory receptors SYNESTHESIA: ➔​ A condition where stimulation in one ➔​ Bottom-Up Processing: occurs sense automatically leads to sensation when we sense basic features of in another sense (Bradford 2017). stimuli and then integrate them. ➔​ a fascinating neurological phenomenon where one sense PERCEPTION: refers to the way sensory triggers responses in another. information is organized, interpreted, and consciously experienced. CHROMESTESIA: ➔​ A subset of synesthesia in which ➔​ Top-Down Processing: occurs when certain sounds are associated with previous experience and expectations colors (Razo, 2019). are first used to recognize stimuli. Functional code: describes how sensory HOW DOES SENSING WORKS? receptors encode information. SENSORY RECEPTORS: specialized cells PSYCHOPHYSICS: the study of our or groups of cells that detect changes in the sensitivity to stimuli of different strengths. environment, like light, sound, touch, temperature, taste, and smell. ABSOLUTE THRESHOLD: is the minimum intensity of a stimulus that is TRANSDUCTION: is how our senses turn required to be detected by a person’s sensory physical stimuli into electrical signals that our system brains can understand. These cells relay messages, in the form of action potentials to the central nervous system. SUBLIMINAL MESSAGES: the stimulus causes an action potential but we are not 5 SENSES: Vision, Audition, Olfaction, consciously aware of it. Gustation, Somato-sensation Other/secret senses: Difference Threshold (Just a ➔​ Vestibular sense (Balance) Noticeable Difference or JND): the ➔​ Nociception (Pain) minimum difference between a pair of stimuli ➔​ Proprioception & Kinesthesia (Body that can be perceived under experimental position & Movement) conditions. ➔​ Thermoception (Temperature) Weber’s Law: relationship between the Anatomical Code: Doctrine of magnitude of a physical stimulus and the Specific Nerve Energies: perceived intensity or strength of the sensation ➔​ First described in 1826 by the German it produces. physiologist Johannes Müller in his doctrine of specific nerve energies. ➔​ A way of explaining how the brain WAVES & WAVELENGTHS interprets different sensory signals based on the specific nerves that carry them. ➔​ AMPLITUDES refers to the height of ➔​ The brain "reads" the anatomical a wave. code, associating the activated ➔​ TIMBRE refers to the quality of pathway with a specific sensation. sound. ➔​ LIGHT WAVES are associated with Localized Brain Function: Different perception of color. areas of the brain are responsible for specific ➔​ WAVELENGTHS refers to the length functions or processes. While the brain works of a wave. as a complex, interconnected network, certain ➔​ FREQUENCY refers to the number of waves.  ➔​ SOUND WAVES are associated see wavelengths ranging from about with various aspects of our perception 380 – 740nm. of sound. AMPLITUDE & WAVELENGTH ➔​ Amplitude is the distance between the wave's resting position and its maximum displacement ➔​ The wavelength of a wave describes SOUNDWAVES how long the wave is. The distance from the "crest" (top) of one wave to the crest of the next wave is the Frequency wavelength. Alternately, we can measure from the "trough" (bottom) of ➔​ Frequency of soundwaves = pitch one wave to the trough of the next ➔​ High frequency = high-pitched sound wave and get the same value for the ➔​ Low frequency = low-pitched sound wavelength. ➔​ The audible range of sound frequencies in humans is between 20 – 2000Hz Amplitude and Decibels ➔​ Amplitude of soundwaves = loudness ➔​ Higher amplitude = louder sounds ➔​ Lower amplitude = quieter sounds ➔​ Loudness is measured in decibels (dB). FREQUENCY ➔​ Typical conversation: 60 dB Longer wavelengths have lower frequencies ➔​ Rock concert: 120 dB and shorter wavelengths have higher ➔​ Potential for hearing damage: frequencies. ➔​ 80 – 130 dB ➔​ The threshold for pain: 130 dB VISION Our eyes take in sensory information that helps us understand the world around us. ANATOMY OF THE VISUAL SYSTEM LIGHT WAVES ➔​ The visible spectrum is the portion of the electromagnetic spectrum that we can see. ➔​ Different species can see different portions of the spectrum. ➔​ Humans can see wavelengths ranging from about 380 – 740nm.Humans can  1.​ Light waves are transmitted across the ➔​ Involved in the perception of cornea and enter through the pupil. movement in our peripheral vision. 2.​ The pupil’s size is controlled by ➔​ Located in the periphery of the retina. muscles that are connected to the iris (the colored part of the eye). OPTIC CHIASM 3.​ The light crosses the lens and is The place in the brain where some of the optic focused on the fovea, which is part of nerve fibers coming from one eye cross optic the retina. nerve fibers from the other eye. 4.​ The fovea contains photoreceptors. 5.​ Photoreceptors are connected to The optic nerve of each eye merges at the retinal ganglion cells. Axons from optic chiasm, an X-shaped structure just below these cells exit through the back of the the cerebral cortex. eye where they form the optic nerve. 6.​ The optic nerve then carries the visual ➔​ Information from the right visual field is information to the brain. sent to the left hemisphere and information from the left visual field is Blind spot – a point of no receptors, sent to the right hemisphere. where information exits the eye, where ➔​ This information is then sent to the we cannot respond to visual occipital lobe for processing. information. PHOTORECEPTORS Cones: Cones are a type of photoreceptor cell in the retina. They give us our color vision. VISUAL PATHWAYS Cones are concentrated in the center of our After being processed in the occipital lobe, retina in an area called the macula and help us visual information exits and goes through see fine details. two different pathways Photopic (daytime) vision. The “WHAT” pathway ➔​ Work best in bright light conditions. ➔​ Object recognition. ➔​ High-acuity color information. ➔​ Object identification. ➔​ Located in the fovea. ➔​ Rods Scotopic (nighttime) vision. The “WHERE/HOW” pathway ➔​ Work best in low light conditions. ➔​ Location in space. ➔​ High-sensitivity. ➔​ How one might interact with a ➔​ Allows for low-acuity vision in dim particular visual stimulus. light. COLOR VISION AUDITION Our ears take in sensory information that helps Trichromatic Theory of Color us understand the world around us. Vision: All colors can be produced by combining red, green, and blue. ANATOMY OF AUDITORY SYSTEM Opponent-Process Theory: Some cells are excited by one of the opponent colors and are inhibited by the other. Afterimage - continuation of a visual sensation after removal of the stimulus. Research has found that both theories are true but for different parts of the visual system. The ear is divided into 3 divisions: DEPTH PERCEPTION: our ability to perceive ➔​ Outer Ear contains the pinna, the ear spatial relationships in 3-D. Depth cues of a canal, and the eardrum. visual scene are used to establish our sense ➔​ Middle Ear contains the ossicles and of depth. the oval window. ➔​ Inner Ear contains the cochlea, Depth Cues: specifically the organ of Corti, the receptor for hearing. Binocular cues - cue that relies on the use of both eyes. PITCH PERCEPTION ➔​ Binocular disparity - slightly different Temporal Theory view of the world that each eye ➔​ Frequency is coded by the activity receives. level of a sensory neuron. ➔​ Monocular cues – cue that relies on ➔​ Problem – the frequency of action only one eye. potentials cannot account for the ➔​ Linear perspective – when two parallel entire range that we are able to hear. lines seem to converge. There is a point at which a cell cannot ➔​ Interposition – the partial overlap of fire any faster. objects. Place Theory Presbyopia: loss of ability to accommodate ➔​ Different portions of the basilar due to aging. membrane are sensitive to sounds of different Myopia: near sightedness. ➔​ frequencies. ➔​ The base responds to high Hyperopia: farsightedness. frequencies and the tip responds to low frequencies. Color Blindness: inability to distinguish ➔​ Both theories explain different aspects certain colors from one another affects of pitch perception. 7% of males and 1% of females. And, loss of ➔​ The rate of action potentials applies up ability to accommodate due to aging. to about 4000Hz but higher frequencies can only be encoded using place cues.  taste buds that can detect five primary SOUND LOCALIZATION tastes: sweet, salty, sour, bitter, and Localizing sound involves the use of umami (savory). two cues: ➔​ the taste buds send signals to the brain, allowing us to experience and Monaural cues: distinguish different flavors. ➔​ One ear ➔​ Each ear interacts with incoming ANATOMY OF TOUNGE ➔​ sound waves differently. Binaural cues: ➔​ Two ears ➔​ Provide information on the location of sound along a horizontal axis. ➔​ Relies on differences in patterns of vibration. ❖​ Interaural level difference – sound coming from one side of the body is more intense at the closest ear Taste pore - small opening on the surface of because of the attenuation of the the tongue that allows molecules from food sound wave as it passes through the and beverages to enter and reach the sensory head. cells within taste buds. ❖​ Interaural timing difference – small difference in the time at which a given Taste Receptor Cell - responds to different sound wave taste qualities — sweet, sour, bitter, salty, and umami. These receptors send signals to the HEARING PROBLEMS brain, initiating the perception of taste. ➔​ Conductive hearing loss: Associated with a failure in the vibration of the Nerves - they transmit signals through nerves. eardrum and/or movement of the This transmission of signals allows the brain to ossicles. This can often be dealt with interpret and recognize different tastes. using hearing aids which amplify incoming sound waves to make the Tongue surface - is vital for gustation, It vibration of the eardrum and contains taste buds clustered within papillae, movement of the ossicles more likely which are small structures on the tongue. to occur. ➔​ Sensorineural hearing loss: failure to OLFACTION (SMELL) transmit neural signals from the cochlea to the brain. Can be caused by Meniere ’s disease which results in degeneration of inner ear structures. CHEMICAL SENSES Sensory receptors that respond to molecules in the food we eat or in the air we breathe. GUSTATION ➔​ also known as taste, is one of the five senses and refers to the perception of flavors from substances in the mouth. Olfactory receptor cells: Contain small The human tongue is equipped with hair-like extensions which serve as the site for odor molecules to interact with chemical receptors located on these extensions travels up the spinal cord directly to (Located in a mucous membrane at the top of the brain, specifically the medulla, the nose). thalamus and the somatosensory cortex. Pheromones: ➔​ Chemical messages sent by another PAIN PERCEPTION individual. Pain perception is important because it ➔​ Many species respond to pheromones motivates us to remove ourselves from the sent by another individual. cause of injury. ➔​ Usually communicate information about the reproductive status of a ➔​ Inflammatory pain – signals some potential mate. type of tissue damage. ➔​ Neuropathic pain – caused by OTHER SENSORY SYSTEMS damage to neurons of either the sensory systems that provide information peripheral or central nervous system. about balance, body position and movement, pain, and temperature. THE VESTIBULAR SENSE Vestibular sense – Also known as “balance SOMATOSENSORY (TOUCH) sense”. There are many types of sensory receptors located in the skin, each attuned to specific The vestibular system is a system that touch-related stimuli. provides a sense of balance as well as information about the state of the body, ➔​ Meisnerr’s corpuscles – respond to allowing for quick adaptations in reaction to pressure and lower-frequency both one's own and externally provided stimuli. vibrations. ➔​ Pacinian corpuscles – detect PROPRIOCEPTION AND KINESTHESIA transient pressure and ➔​ Proprioception - perception of body higher-frequency vibrations. position. ➔​ Merkel’s disks – respond to light ➔​ Kinesthesia – perception of the body’s pressure. movement through space. ➔​ Ruffini corpuscles - detect stretch. PERCEPTION FACTORS AFFECTING PERCEPTION 1.Sensory adaptation is a reduction in sensitivity to a sensory stimulus after constant exposure to it. ​ Sensory deprivation or perceptual isolation is the deliberate reduction or removal of stimuli from one or more of the senses. THERMOCEPTION & NOCICEPTION As well as receptors located in the skin, there 2.Selective attention the act of focusing on a are a number of free nerve endings that have particular object for a while,simultaneously sensory functions. ignoring distractions and irrelevant information. ➔​ Thermoception – temperature ​ Inattentional blindness - failure to perception. notice something that is completely ➔​ Nociception – sensory signal visible because of a lack of attention. indicating potential harm and maybe pain. This type of sensory information 3. Motivation ​ Signal detection theory – change in stimulus detection as a function of current mental state. 4. Beliefs, values, prejudices and expectations 5. Life/Cultural experiences MULLER-LYER PERCEPTION The idea is that things that are close to one ❖​ In the Muller-Lyer illusion, lines another tend to be grouped together. appear to be different lengths although they are identical. The Gestalt principle of proximity suggests that you see (a) one block of dots on the left GESTALT PRINCIPLES OF PERCEPTION side and (b) three columns on the right side. Gestalt psychology – field of psychology based on the idea that the whole is different GESTALT PRINCIPLE OF SIMILARITY from the sum of its parts. The brain creates a perception that is more than simply the sum of available sensory inputs. Principles include: ➔​ Figure-ground relationship ➔​ Proximity ➔​ Similarity ➔​ Continuity ➔​ Closure FIGURE-GROUND RELATIONSHIP The idea that things that are alike tend to be grouped together. When looking at this array of dots, we likely perceive alternating rows of colors. GESTALT PRINCIPLE OF CONTINUITY The idea that we tend to segment our visual world into figure and ground. Figure – the focus of the visual field. Ground – the background. Our perception can vary depending on what we view as figure and what we view as ground. GESTALT PRINCIPLE OF PROXIMITY The idea that we are more likely to perceive continuous, smooth flowing lines rather than jagged, broken lines. GESTALT PRINCIPLE OF CLOSURE The idea that we organize our perceptions into complete objects rather than as a series of parts. Closure suggests that we will perceive a complete circle and rectangle rather than a series of segments.