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Psychology Day 13.docx

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Lawrence Murphy

Psychology Day 13 Chapter 6 Lecture: Monday, October 29 Sensation and Perception  Sensation o The detection of physical energy emitted or reflected by physical objects o Occurs when energy in the external environment or the body simulates receptors in the sense organs  Perception o Process by which the brain organizes and interprets sensory information Separate Sensations?  Sense receptors o Specialized cells that convert physical energy in the environment or the body to electrical energy that can be transmitted as nerve impulses to the brain o Dendrites of sensory neurons responsible for smell, pressure, pain and temperature o Specialized cells for vision, hearing and taste  Doctrine of specified nerve energies (Muller) o Principle that different sensory modalities exist because signals received by the sense organs stimulate different nerve pathways leading to different areas of the brain  Could essentially if technology existed allow you to see things as a result to noise o If possible allows for sensory substitution o Sensory crossover also occurs in synesthesia where simulation of one sense consistently evokes the sensation of another Measuring the Senses  Psychophysics o Field concerned with how the physical properties of stimuli are related to our psychological experience of them  Absolute threshold o The smallest quantity of physical energy that can be reliably detected by an observer (50% of the time) o Senses are sharp but only tuned into narrow band of physical energies  Think of all the different wave lengths we cannot see  Difference threshold o Smallest difference in stimulation that can reliably be detected by an observer when two stimuli are compared  Think of clapping demo in class o Also called the just noticeable difference (JND) o Weber’s law: size of JND is proportional to size of initial stimulus th o JND for weight is 1/30  So you could tell the difference between 300 grams and 310 grams  Signal detection theory o Divides the detection into a sensory process and a decision process o False alarm is type 1 error (false positive) o Miss is type 2 error (false negative)  Can manipulate people into giving false positives and false negatives Sensory Adaptation and Sensory Deprivation  Sensory adaptation o Reduction or disappearance of sensory responsiveness when stimulation is unchanging or repetitious  The noise of a fan or smell of a room goes away, you can hear/smell it but youre not perceiving it  Frog in kettle metaphor o Useful as it spares us from responding to unimportant information  Sensory deprivation o The absence of normal levels of sensory stimulation o Varied responses somewhat dependent on expectation and interpretations (hallucinations) o Common torture method Sensing Without Perceiving  Selective attention o Focusing of attention on selected aspects of the environment and blocking out the others  Unintentional blindness o Failure to consciously perceive something you are looking at because you are not attending to it  Background noise at a party, seeing someone you haven’t seen in a long time in a crowded area won’t recognize them Vision: The stimulus  Light is the stimulus=electromagnetic radiation o Amplitude: perception of brightness o Wavelength: perception of colour (hue) o Purity: mix of wavelengths  Essentially the saturation or richness of colours  Light stimuli (waves) have physical characteristics o Hue  Perception of colour, wavelength o Brightness  Amplitude of wave length o Saturation  The richness of colours, how intense the colour is, white light is no colour, fully saturated is really rich colour An Eye on the World  Cornea: protects eye and bends light toward eyes  Lens: focuses on objects by changing shape  Iris: controls amount of light that gets into eye  Pupil: widens or dilates to let more light in The Retinal Image  Image is displayed upside down on retina and blind spot is filled in by brain if object is continuous  Retina: o Neural tissue lining the back of the eyeball’s interior, which contains the receptors for vision o Rods: visual receptors that respond to dim light (also focus on black and white)  120-125 million concentrated in the periphery of the retina  Highly sensitive to light (used for night vision) o Cones: visual receptors involved in colour vision  low sensitivity to light  7-8 million located in centre of the retina The Retina  We experience chemical changes in rods and cones when our eyes adjust fully to dim illumination o Commonly called dark adaptation  Retinal processing also involves ganglion cells o Neurons in the retina that gather information from receptor cells o Axons form the optic nerve which forms the optic disk Vision is Not Like A Camera  Visual processing is an active process and involves many types of cells in different brain regions o Cortical cells respond to lines of specific orientations, others respond to properties of shapes and arrangements (spirals, faces and greebles)  Feature Detector Cells o Cells in the visual cortex that are sensitive to specific features of the environment Constructing the Visual World  We rely on Gestalt principles to organize visual input o Figure: item of interest that stands out from the rest of environment o Ground: environment or background  Gestalt Principles: o Proximity:  Elements that are close to one another tend to be grouped together o Closure:  Viewers tend to supply missing elements to close or complete a familiar figure  Circle with a piece missing is still a circle in my mind o Similarity  Elements that are similar tend to be grouped together o Simplicity  Viewers tend to organize elements in the simplest way possible o Continuity  Viewers tend to see elements in ways that produce smooth continuation Visual Constancies  Another important perceptual skill is perceptual constancy o The accurate perception of objects as stable or unchanged despite changes in the sensory patterns they produce  Best studied are: shape, location, size, brightness and colour constancies Psychology Day 14 Lecture: Wednesday, October 31 Chapter 6 How we See Colour  Trichromatic theory o Proposes three basic types of cones each sensitive toa certain range of wavelengths (red, blue, green) o Interaction of activity in three cones assumed to produce all the different experience of hue (colour) o Colour blindness- typically a genetic variation causing the absence or dysfunction of one or more of the cones  Most are actually colour deficient meaning the person is unable to distinguish red and green (see everything as blue, yellow, brown and grey  Occurs most often in white male and is rare in women  Opponent-process theory o Assumes that the visual system treats pairs of colours as opposing or antagonistic o Occurs in the ganglion cells and neurons in thalamus and visual cortex o Three opponent pairs:  Red and green  Yellow and blue  Black and white  Cells that are inhibited by one colour, produce burst of firing when opponent colour is presented o Often leaves people with a negative afterimage  The cells that are inhibited by opponents still fire after the opponent colour is removed o The idea is related to the fact that you have a variety of cones that interpret colour with wavelengths not by pure colour which creates opponent pairs Visual Illusions  Our systems are sometimes fooled when making sense of the world  Perceptual illusions give us information about perceptual strategies used by brain and how misleading messages are interpreted  Muller-Lyer illusions have to do with outside and inside corners and which looks taller or longer  Ames room uses the assumption that the brain will automatically assume a room is parallel and floors are flat and are able to fool the brain into seeing a really short and tall person Hearing  Audition refers to our sense of hearing  Three physical characteristics of sound waves that alter psychological experience of sound o Loudness: intensity/amplitude of pressure wave (dB) o Pitch: Frequency of pressure waves (Hz); height or depth of tone o Timbre: complexity of pressure way distinguishing NOTES An Ear on the World  Cochlea o Snail-shaped fluid filled organ in the inner ear containing the structure where the receptors for hearing are located  Organ of Corti o Structure in the cochlea containing the hair cells (cilia) that are the auditory receptors  Basilar membrane o NOTES Structures of the Ear  Eardrum o Oval shaped membrane  Hammer, anvil and stirrup o Three bones that intensify the force of the vibration  They increase the power of the intensity  The information from the eardrum (sound) gets transferred to these bones  Gets translated into electronic data which gets sent along auditory nerve Constructing the Auditory World  Patterns of sound also organized to construct meaningful patterns  Gestalt principles can also relate to sound perception o See textbook for auditory scenes  Sound localization- relies on loudness and intensity of stimuli to tell us where a sound is coming from o Happens because of when the sound appears in each ear and brain localizes it based on difference in time o The head behaves like a shadow for the sound so sound is stronger on one side or even depending on where sound is coming from Taste (Gustation)  Papillae o Knoblike elevations on the tongue o Contains taste buds (contain the taste receptor cells) o 5 main tastes:  Salty  Sour  Sweet  Bitter  Umami o Genetic differences in amount of papilla and the insensitivity of taste buds o Culture, learning and food attractiveness influence preferences  In Japan they focus on texture and flavour is minimal  Culture explains the differences in cuisine  We cringe at the thought of eating dog which is normal in some parts of the world o Supertasters  Individuals who have more taste buds and smaller papilla  Find some foods unpleasantly bitter Smell (olfaction)  Receptors in each nasal cavity respond to chemical molecules in air o Receptors react to volatiles in the air and the information goes straight to the cortes  Only one of our main senses that does not get processed first by thalamus  This is why we think smell can recall memories o Trigger reactions in olfactory bulb and then straight to cortex with no intermediate processing  We can distinguish between roughly 10 000 smells  Smell is so critical because it is essential in detecting danger (smoke, food, spoilage, gas leak, etc.)  Sense of smell sometimes lost through infection, disease, injury, or smoking  Smokers (2 packs a day) must abstain 10 years for smell to return to normal  Psychological effects of smell include evoking memories and emotions but may also include evoking behaviours Skin Sensations  Basic skin senses: o Touch (pressure), warmth, cold and pain o Certain spots on skin especially sensitive to 4 basic sensations  Hands, feet, face, the D etc. o Pain differs from other skin senses  When stimulus producing pain is removed, the sensation may continue (chronic pain)  Hard to get out of bed, bad mood, depression Theories of Pain  Gate-control theory of pain o The experience of pain depends in part on whether pain impulses get past a neurological “gate” in the spinal cord and reach the brain  Neuromatrix theory of pain o Matrix of neurons in the brain is capable of generating pain (and other sensations) in the absence of signals from sensory nerves  This generally is when the placebo effect works o Accounts for phantom pain The environment within  Kinesthesis o Sense of body position and movement of body parts  Equilibrium o Sense of balance o Influenced by semicircular canals: sense organs in the inner ear that contribute to equilibrium by responding to rotation of the head Perceptual Powers  Is perception hard-wired or influenced by learning o Inborn abilities:  Infants born with basic sensory abilities rapidly develop  Depth perception and visual cliff experiments  Babies will crawl out over cliff (plexiglass) up to a certain age o Critical periods:  Crucial windows of time during which a person must have certain experiences or perception will be impaired  Classic studies with kittens in controlled environments (visual perception) Psychology Day 15 Arden’s Gay and Chapter 14 Lecture: Monday, November 5  Phantom Pain o Pg 220 o Continuous pain experienced by amputees o Using a mirror they found a cure that made it seem like they had2 limbs and the brain thinks you have 2 legs and there is no pain magically o It tricks the brain out of pain permanently because once the brain realizes once the sensation never returns o Cognitive neuroscience  Neuroscience (science with biology of the brain) as well as cognitive research (psychology)  Measures brain waves and relates them to certain behaviours o Parkinson’s Disease  Tremors  Rigidity  Slowness of movement  Impaired balance  Shuffling gait (weird walk)  Speech and swallowing issues  Fatigue  Mask-like face (no emotions)  Impaired motor control  Impaired cognition  Usually occurs in elder years  Can be fatal  People with Parkinson’s  Slowed though process  Poor problem solving  Mood swings o Anxiety, depression  Poor spatial skills  Dopamine levels in a Parkinson’s patient are lower and do not operate properly  Although it is associated with motor skills there are also many issues with problem solving and thought process o His Undergraduate Thesis  Politics and psychology  Personality traits o Analyzed how certain personality traits affect our political ideology  Stuff you own  Brain anatomy o Size of certain cortex’s in brain that correlate with political ideology  Genetics o Friends in high school and parents beliefs affecting political ideology  The goal  To create a new way to measure political beliefs  What do eye movements have to do with politics?  Dissonance theory o Much more motivated to search for things that support your political views  Motivated gaze o More likely to look at stuff that you agree with  Subjects reflexively follow the gaze o Will follow the gaze of your political leaders o Research in biopsychology  Animal research  Must go through an animal ethics seminar o Cocaine  Stimulant  Alertness, euphoria, energy, mania  Prolonged use can result in itching, hallucinations, heart problems and addiction  Coca leaves were chewed upon in South
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