University:
College
Course:
College Psychology
Academic year:

2024
Views:

473

Pages:

38
Author:

micikaax

Psychology Sensation, Perception and States of Consciousness Essential Task 4-1: Discuss basic principles of sensation/bottom up processing with specific attention to sensory transduction, absolute threshold, difference threshold (Weber's Law), signal detection, and sensory adaptation. Gestalt Principles Perceptual Constancies Basic Principles Visual Illusions Depth Perception Perception We are here Sensation Vision Theories The Eye Pain Other Senses Taste Hearing The Ear Smell Theories Stages/REM Meditation Circadian Rhythm Hidden Observer Disorders Sleep Hypnosis Dreams Altered States of Consciousnes s States of Consciousness Daydreaming and Fantasy Drug-Altered Consciousnes s Stimulants Waking Consciousness Substance Abuse Depressants Hallucinogens Actor Essential Task 4-: Outline • Sensation/bottom-up processing • Perception/top-down processing • Transduction • Absolute threshold • Difference threshold – Weber's Law • Signal detection • Sensory adaptation Sensation Perception 6-8% Sensation vs. Perception Outline • Sensation – The experience of sensory stimulation (sight, hearing, touch, taste, smell) – Detecting physical energy from “outside” • Perception – The mental process of creating meaningful patterns from raw sensory information What do you see vs. what do you perceive? Outline What do you see vs. what do you perceive? Outline What do you see vs. what do you perceive? Outline II. Bottom Up vs. Top Down Processing (analyzing information) Outline Perception Bottom-up Processing (sensation) Works with the details and moves out to the whole. Stimulus -> perception • Inductive reasoning • Based upon current knowledge / potentially biased Example: Since 100% of biological life forms depends on liquid water to exist on earth, therefore life forms in other planets require liquid water. Top-Down Processing (perception) Outline Information processing is guided by higher-level mental processes as we construct perceptions, drawing on our prior experiences and expectations. Background knowledge -> Perception THE CHT We look at the whole to find a pattern to make meaning in the details. Top-Down Processing What do you see as a whole? Example of Top-Down Processing Outline • Aoccdrnig to rscheearch at Cmabrigde Uinervtisy, it deosn't mttaer in waht oredr the ltteers in a wrod are, the olny iprmoetnt tihng is taht the frist and lsat ltteer be at the rghit pclae. The rset can be a total mses and you can sitll raed it wouthit a porbelm. Tihs is bcuseae the huamn mnid deos not raed ervey lteter by istlef, but the wrod as a wlohe. Stroop Effect: Tell me what colors you see below Red Green Purple Red Black Bottom-up Processing Outline Analysis of the stimulus begins with the sense receptors and works up to the level of the brain and mind. Letter “A” is really a black blotch broken down into features by the brain that we perceive as an “A.” Perception without Sensation? Phantom limb is the sensation or pain that an amputated or missing limb is still attached. • Even though your limb might be gone, your neural connection is still present—allowing one to still experience the limb Perception without Sensation? • sensory deprivation can result in extreme anxiety, hallucinations, bizarre thoughts, and depression. result of the brain amplifying neural noise in order to look for the missing visual signals • Psychotic hallucinations Sensation without Perception? • Prosopagnosia (face-blindness) • Inability to recognize faces • They see eyes, nose, ears, and mouth, but they are unable to put those them together • Sensation is present but perception is not! https://www.youtube.com/watch?v=q8c Xus7SNQY Attention • Selective Attention – Your conscious awareness focuses on a particular stimulus • Inattentional Blindness – Failing to see visible objects when our attention is directed elsewhere – https://www.youtube.com/watch?v=Ahg6qcgoay4 (basketball) – https://www.youtube.com/watch?v=GZGY0wPAnus (misdirection) – https://www.youtube.com/watch?v=ubNF9QNEQLA (who done it?) Change & Choice blindness Change Blindness • observers fail to notice changes in their visual field (environment). – https://www.youtube.com/watch?v=diGV83xZwhQ – https://www.youtube.com/watch?v=VkrrVozZR2c Choice blindness • refers to a short-term memory phenomenon that causes people to be unable to accurately recall choices made. – https://www.youtube.com/watch?v=wRqyw-EwgTk Cocktail Party Effect • phenomenon of the brain's ability to focus one's auditory attention (an effect of selective attention in the brain) on a particular stimulus while filtering out a range of other stimuli III. Transduction 1) Receptor cells • Specialized cells that respond to a particular type of energy 2) Transduction • external energy is converted to neural signals. • Conversion of one form of energy into another. Transforming stimulus energy (sight, sound) into neural impulse. • then sent to the thalamus, which sends them to other parts of the brain • exception: smell The Basic Process Outline • Receptor cells – Specialized cells that respond to a particular type of energy • Transduction – external energy is converted to neural signals. • Doctrine of specific nerve energies – One-to-one relationship between stimulation of a specific nerve and the resulting sensory experience – For example, applying pressure with your finger to your eye results in a visual experience (flash of lights) IV. Absolute Threshold Outline • Minimum stimulation needed to register a particular stimulus 50% of the time – Smallest detectable LEVEL of a stimulus. Absolute Thresholds Outline • Taste: 1 gram (.0356 ounce) of table salt in 500 liters (529 quarts) of water • Smell: 1 drop of perfume diffused throughout a three-room apartment • Touch: the wing of a bee falling on your cheek from a height of 1cm (.39 inch) • Hearing: the tick of a watch from 6 meters (20 feet) in very quiet conditions • Vision: a candle flame seen from 50km (30 miles) on a clear, dark night Detection must be 50% of time. Outline Absolute Threshold Intensity No No No Yes Yes Observer’s Response Detected Tell when you (the observer) detect the light. Subliminal Threshold Outline Subliminal Threshold: When energy of the stimulus is below one’s absolute threshold for conscious awareness. What do we perceive then? V. Difference threshold Outline – Minimum difference between two stimuli required for detection 50% of the time, also called just noticeable difference (JND). – The smallest detectable CHANGE in stimulus Example: – 1 once is added on 10 ounce weight vs – 1 ounce is added to 100 ounce weight VI. Weber’s Law Outline Two stimuli must differ by a constant minimum percentage/proportion (rather than a constant amount), to be perceived as different. More than just sensation it has to do with scales. Weber fraction: k = dI/I. https://www.youtube.com/watch?v=wVhiezByMSU Stimulus Light Weight Tone Constant (k) 8% 2% 3% VII. Signal Detection Theory (SDT) Outline Predicts how and when we detect the presence of a faint stimulus (signal) amid background noise (other stimulation). SDT assumes that there is no single absolute threshold and detection depends on: • Person’s experience • Expectations • Motivation • Level of fatigue Examples of Signal Detection • Important vs. Irrelevant – Baby crying for new parents – Driving a new car – hear an odd noise VIII. Sensory adaptation Outline • An adjustment of the senses to the level of stimulation they are receiving – Ever forgotten you are wearing a watch? – Ever gotten used to a smell? How does your car smell? – Adopting to hot or cold water – Eyes adjusting in a darkroom Outline Sensory Habituation • After a frequent and repeated exposure of the stimuli leads to reduced response • Reduced response to something that used to elicit a strong response – Response to drugs (tolerance) – Not being able to hear traffic noise or subway