Sensation and Perception PDF

Sensation SENSE STIMULUS RECEPTOR TRANSMISSORS BRAIN CENTER VISION Light waves Rods and cones Optic nerve Primary visual area HEARING Sound waves Ear Cochl...

Sensation SENSE STIMULUS RECEPTOR TRANSMISSORS BRAIN CENTER VISION Light waves Rods and cones Optic nerve Primary visual area HEARING Sound waves Ear Cochlear nerve Primary auditory area TASTE Chemical (liquid Taste buds Facial & Primary gustatory form) glossopharyngeal nerve SMELL Chemical (gaseous Olfactory cells Olfactory nerve Olfactory areas state) TACTILE Touch, pressure, Touch - Markel’s Peripheral sensory Primary pain, cold, and Disk neurons somatosensory warm Pressure - Pacinian cortex Corpuscles Pain - Free Nerve Endings Cold - Krause’s Corpuscles Warm - Ruffini’s Endings SENSE ENVIRONMENTAL ORGAN SENSATION RECEPTOR CELLS STIMULUS TOUCH Pressure, pain, Skin Tactile / Cutaneous Mechanoreceptor temp SMELL Chemicals (air) Nose Olfactory Olfactory receptor TASTE chemicals Tongue Gustatory Taste receptor cells SIGHT Light waves Eyes Visual photoreceptors HEARING Sound waves Ears Auditory Hair cells Sensation Stimulation of sensory receptors and transmission of sensory information to the CNS (brain) Ex. may narinig ka (boses ng mama mo) Perception selecting , organizing, and interpreting sensory information to recognize meaningful objects and events Ex. narealize mo kung ano yung narinig mo (tinatawag ka para kumain) Transduction Sensory systems convert external stimuli into neural signals (action potential) Our bodies are made up thousand of sensory receptors Process of converting energy of a stimulus into neural activity The sixth sense: Kinaesthesia Part of the tactile sensation Awareness of the position and movement of the parts of the body using sensory organs Informs you about the position and motion of the parts of the body Receptors reside in joints, muscles, tendons (proprioceptors) External Sensation 1. Stimulus a. Any aspects of the world that influences our behavior b. Physical element c. Absolute threshold - minimum amount of stimulus that is capable of producing a sensation 2. Receptor a. Any structure in the body that is excitable to a stimuli 3. Transmissors a. Bundles of nerve fibers that convey sensory messages or impulses from one neuron to the next b. Fiber tracts - transmitting the sensory impulses to the brain 4. Brain center a. Continuous with the spinal cord from which it emerges Psychological Characteristics of Sound 1. Frequency a. Rate of vibrations of sound wave which determines the pitch (the high/low of the sound) 2. Intensity a. Density of vibrating air molecules b. Loudness of the sound c. Loudness is measured in decibel (dB) 3. Complexity a. Timbre or the tonal quality Loss of External Sense 1. Anopsia - blindness 2. Anacousia - deafness 3. Anosmia - loss of smell 4. Ageusia - loss of taste 5. Analgesia - failure to feel pain 6. Astereognosis - failure to identify object through touch Perception Sensation Stimulation of visual receptor Perception Electrochemical signals are selected, organized, and interpreted Mind’s interpretation of sensation The result of the brain’s analysis of sensation Visual Perception: 2 Different Streams  Dorsal Stream “Where” Spatial awareness and guidance awareness Detailed map of the visual field Detecting and analyzing movements Ventral Stream “What” Object recognition Form representations Prosopagnosia - can see faces but have a hard time recognizing their identities Tactile Perception Primary Somatosensory Cortex Located behind the central sulcus Neurons here are activated when the skin is touched Map of the human Drawn by Dr. Wilder somatosensory cortex Penfield, a neurosurgeon in the 1950s Homunculus Distorted body map “Little man” People who don’t experience physical pain Frontal Lobe: Periaqueductal Gray Blocks the pain receptors Electrical stimulation of the periaqueductal gray matter reduces the perception of pain  How smell triggers memory Olfactory cortex Very close with the memory centers of the brain like the hippocampus and amygdala Characteristics and Nature of Perception Subjective reality Influenced by beliefs, feelings rather than basing on facts Not constant Very dynamic, always changing Changes with age, life events, or a new piece of information Influenced of your expectations, prior knowledge, Age, gender, ethnicity, culture, values, beliefs, personal characteristics, and background experience, religion, and other factors of the human condition The Gestalt Laws of Organization The Phi Phenomenon alternately flashing lights, such as neon signs or strands of lights, can look like a single light that is moving back and forth Discovered by German psychologist Max Wertheimer Basis for Gestalt psychology our mind fills in missing information series of still images appearing in rapid succession to form a seamless visual experience Wolfgang Köhler and Kurt Koffka, developed a set of rules to explain how we group smaller objects to form larger ones Gestalt laws of perceptual organization Pragnanz (Law of Good Figure / Every stimulus pattern is Law of Simplicity) seen in such a way that the resulting structure is as SIMPLE AS POSSIBLE people will perceive and interpret complex images in the simplest form  possible in a way that demands less cognitive effort Figure and Ground Figure - images we see and focus on Ground - blurred in the background or in our peripheral vision We can easily and readily shift our focus Are and condensity Developed by Edgar Rubin (1915), the now popular Rubin Vase Similarity Objects in our environment are grouped together and perceived as one entity based on similarity: color, shape, size, texture, etc. Ex. We tend to describe this image as alternating rows of triangles and circles instead of columns of triangles and circles Closure Tend to see a whole and complete image even if it is not because some parts are missing We combine parts to form a simpler whole human tendency to seek and find patterns Proximity We also group entities in our world based on proximity or nearness in space or distance asserts that visual elements positioned close to each other are perceived to be related or grouped  Common Region Another way to show a connection between elements is to enclose them in some way Everything inside the enclosure is seen as related Good Continuation Objects arranged in either a straight line or a smooth curve also tend to be seen as a unit Common Fate Seeing objects move in the same direction at almost the same speed, we perceive the entire group of these objects as a unified whole Meaningfulness or Familiarity things that form patterns that are familiar or meaningful are likely to become grouped together Perceptual Constancies Our ability to understand that an object’s size, shape, brightness, or orientation will stay the same even though it has a different retinal image Size Objects are perceived to have the same size no matter how far or near it is from us Shape Regardless of the angle of your view of an object, its shape is constant in your perception  Brightness Refers to our tendency to see brightness as remaining at the same intensity even when illumination is changing The lightness or darkness of an object remains the same regardless of the intensity of light bouncing off it Color a process that allows the brain to recognize a familiar object as being a consistent color regardless of the amount or wavelengths of light reflecting from it at a given moment The visual system's ability to perceive the stable color of an object despite changes in illumination, relying on responses from multiple objects and a broad range of wavelengths to maintain consistent color appearance Categories of Perception Depth Perception Monocular Cues Require the use of only one eye Binocular Cues See the depth by using both eyes Monocular Cues  Relative Size If an image contains an array of similar objects that differ in size, we interpret the smaller object as being farther away Superimposition / Interposition If one object is positioned so that it obstructs the view of another, we perceive the overlapping / blocking object is nearer Relative Height Among similar objects, those that appear higher are perceived as being farther away Linear Perspective When parallel lines appear to converge, they are perceived as vanishing in the distance Motion Parallax The relative movement of objects at different distances from the observers Aerial Perspective Faraway objects often appear less clear in color and detail Texture Gradient Distant objects have a smoother texture that nearby objects Fine details in nearby objects can be seen clearly, whereas such details re not visible on faraway objects  Binocular Cues Disparity Based on the difference between the retinal images on the two eyes when we look at an object from a distance Retinal disparity - the merging of slightly different images coming from two eyes Convergence It results from the fact that our eyes are a couple of inches apart Motion Perception We perceive motion using certain cues in the environment as well through the natural movements of the eye When we look at a passing plane in the sky, our eyes tend to follow the plane across the background of the sky. Therefore the image perceived by our eyes would have a stationary airplane because our eyes are following it creating a stationary image projected on the retina and perceived by the brain. The movement of the eyes provides the important clue for the brain that what its perceiving is moving since the eyes are moving to follow the object Stroboscopic Effect Wherein two different sources of light are flashed in fast succession We do not see to light sources but on light moving back and forth Subliminal Perception “Below threshold” Perceptions that are formed even if they are based on sensations that do not go above the absolute threshold Subliminal Messages Targeted to influence people without them noticing, rendering them unable to make conscious decisions about the messages they are consuming Backmasking An audio recording of speech, whisper, or singing is played backwards into the original recording and is therefore not detectable consciously Sub-visual Messaging Frames that are flashed quickly in a video for a fraction of a second “priming” Embeds Static images that are embedded into another image, hidden in plain sight Subtle cues to get some message across, that you don’t recognize immediately but your brain might still store them  Extrasensory Perception Sensing or receiving information beyond normal sensory channels such as telepathy and telekinesis Parapsychology - study of variety of proposed psychic phenomena by scientists and scholars Clairvoyance The ability to see things and events that are happening far away and locate objects, places Precognition The ability to perceive or gain knowledge about future events without using induction or deducting from known facts Telepathy The ability to transmit or receive thoughts supernaturally Telekinesis Move, manipulate or otherwise interact with matter/energy without physical means 2 Kinds Of Errors Hallucinations Where an individual perceives some stimulus, even when it is not present This person may see an object, person, etc. They may listen to some voices though there are no objects and sounds in reality Schizophrenia, emotionally disturbed, alcoholics, and those who are in confused states Anaesthesia - no sensation Hyperesthesia - excessive sensitivity Paraesthesia - distorted or wrongly localized sensation Illusions False perceptions on which an individual perceives a stimulus incorrectly It can be a visual, auditory, or cognitive phenomenon that tricks our brain into perceiving something that is not actually there Arises from mismatch between the brain’s interpretation and the reality of the natural world Something that deceives or misleads our senses or perception of reality Types of Illusions Literal Illusions Illusions that are seen in daily life Physiological Illusions Illusions that use color and motion to create an after-effect image Cognitive Illusions Our mind makes assumptions about the environment around us and therefore leads to unexplainable events Types of Cognitive Illusions Ambiguous Illusions Images that shift on the perception of the viewer Impossible images → you can’t have two things exist in one picture  Paradox Illusions Impossible objects Physics and the 3-dimensional space can’t explain how the objects are possible Distorting Illusions Geo-metical optical illusions Distort size, length, curvature, and position to create an image that seems contorted In Fiction Illusions Viewer created an object that doesn’t actually exist in the image Which exists entirely as a product of the mind that is only visible to one individual