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PSYCH 101 CHPT. 9

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Department
Psychology
Course Code
PSYC 101
Professor
Barbara Cox

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PSYCH 101 007 CHPT. 9 CONSCIOUSNESS I. Consciousness as a Social Phenomenon Can We Understand Consciousness?  Historically, 3 philosophical positions about nature of consciousness: 1. Consciousness is not a natural phenomenon, it is something supernatural, not to be understood by human mind 2. Consciousness is a natural phenomenon but we cannot understand it b/c of various reasons  Consciousness exists b/c of the nature of human brain but just how this occurs is not known  Our brains may not be simply able to understand biology of subjective awareness  Lack means to study it scientifically 3. People are conscious, this consciousness in produced by the activity of the human brain  Advocated by Donald Hebb The Adaptive Significance of Consciousness  Consciousness is the awareness of mental processes, not the processes themselves  Consciousness is a characteristic that exists in addition to functions such as perception, memory, thinking & planning so why do we need it?  Consciousness is a private experience that cannot be shared directly  We are not conscious of everything about ourselves  We are not equally conscious if the same thing all the time  Blindsight- ability to interact behaviourally with objects while remaining consciously unaware of them Consciousness and the Ability to Communicate  Consciousness can be viewed as by-product of our ability to communicate symbolically  By using words or signs  Physiological basis is activity of the language mechanisms of the brain  Private use of language (thinking to oneself) is clearly conscious  Private non-verbal processes are conscious if we can describe them  We are conscious of external events only if we can think & verbalize about our perceptions of them  Provides us with self-awareness Consciousness and the Control of Behaviour  Our perceptions may differ from the our actions towards external events  Our awareness of voluntary movements may reflect a by-product of other brain activities that initiate behaviour II. Selective Attention  The process that controls our awareness of, & readiness to respond to, particular categories of stimuli or stimuli in a particular location  Attention may be controlled automatically, controlled by instructions or controlled by demands of a particular task we are performing  Attention to visual events tends to act like a spotlight or zoom lens that highlights the events within some spatially contained area  Our attention mechanisms enhance our responsiveness to certain stimuli & tune out irrelevant info  We do not simply process all the info gathered by our sensory b/c brain mechanisms responsible for conscious processing of info have limited capacity  Selective attention acts as the gatekeeper that controls the flow of info Auditory Information  Dichotic listening- task that requires a person to listen to one of 2 different messages being presented simultaneously, one to each ear, through headphones  Shadowing- act of continuously repeating verbal material as soon as it is heard  First experiments on attention used dichotic listening & shadowing  Participants were made to pay attention to only the message they shadowed  The info that entered the unattended ear is lost within a few seconds unless something causes us direct attention to it  Some info by its nature can break through into consciousness  Unattended info undergoes some verbal analysis  we are able to store info temporarily as it comes in  Filtration of the unattended info occurs after the sounds we hear are identified as words Visual Information  Studies using visually presented info indicate that attention can focus on: 1. Location of the info  If a stimulus occurs where we expect it, we perceive it more quickly  If it occurs where we do not expect it, we perceive it more slowly  People can follow instructions to direct their attention to particular locations in the visual field  Mechanism of selective attention sensitizes neural circuits that detect visual stimuli in a particular region 2. Nature of the info (form or physical attribute of the info)  We can only watch one of 2 events happening closely & ignore the other 3. Meaningfulness of the info (its relevance to us)  Change blindness- failure to detect a change when vision is interrupted o Show that we are more sensitive to relevant stimuli than to irrelevant ones so meaningfulness is an important factor in attention  Inattentional Blindness- a failure to perceive an event when attention is diverted elsewhere o Possibly b/c visual stimulation is so complex o People often don’t see a change even when its blatant, once you can see it, you are astonished how obvious it is o It’s shocking how little of the world we actually perceive o Missing the gorilla in the video! (50% of people do) Brain Mechanisms of Selective Attention  Activity of particular regions of the brain is enhanced when people pay attention to particular characteristics of visual stimuli  Found by brain imaging techniques Why is consciousness wrong?  Many reasons….  For one thing, there’s a constant blind spot in your vision  Also, the image on your retina is 2D but you perceive the world in 3  The goal of conscious access isn’t truth, but usefulness-> not a camcorder, doesn’t have to be perfect  Usually there aren’t gorillas, your consciousness assumes stability in the world III. Consciousness and the Brain  Human consciousness is related to speech so then it is related to brain mechanisms that control comprehension & production of speech  For us to be aware of a piece of info, the info must be transmitted to neural circuits in the brain responsible for communicative behaviour  Supported by some cases of human brain damage  Brain damage can disrupt a person’s awareness of perceptual mechanisms without disrupting other functions performed by these mechanisms Isolation aphasia- a language disturbance that includes an inability to comprehend speech or to produce meaningful speech without affecting the ability to repeat speech & to learn new sequences of words  Caused by brain damage that isolates the brain’s speech mechanisms from other parts of the brain  Appear to completely lose awareness of oneself & the environment  Ability to still repeat words & learn new words suggests that consciousness is not simply activity of brain’s speech mechanisms  It is also activity prompted by info received from other parts of the brain concerning memories or events presently occurring in the environment Visual agnosia- inability of a person who is not blind to consciously recognize the identity of an object visually  Caused by damage to the visual association cortex  Not directly aware of one’s own visual perceptions  If pick up object, then can identify it  Visual system still works well enough to initiate appropriate non-verbal behaviours  Hands talk to you, telling you what you had just seen  Ex. cannot recognize object in picture is a gun, but hand makes movements of shooting a gun Split Brain Syndrome  In people with severe epilepsy that cannot be controlled by drugs  Violent storms of neural activity begin in one hemisphere & are transmitted to the other by the corpus callosum  Both sides of the brain engage in wild neural firing & stimulate each other, causing an epileptic seizure  Cutting the corpus callosum of the people to disconnect the 2 cerebral hemispheres reduces frequency of seizures -> called split-brain operation  Normally, cerebral cortexes of left & right hemispheres exchange info through corpus callosum  Each hemisphere receives sensory info from the opposite side of the body & controls muscle movements on that side  With exception of olfactory system  Person sniffing flower only through left nostril, only left brain receives sensation of the smell  Corpus callosum coordinates this so each hemisphere knows what is going on in the other  When the 2 hemispheres are disconnected, they operate independently, cannot exchange info  A person with split brain can make perceptual judgements with right hemisphere but he are she cannot talk about them & appears to be unaware of them b/c the left hemisphere controls speech  Split brain patients also report that their left hand seems to have a mind of its own  Effects of cutting the corpus callosum reinforce that consciousness depends on ability of speech mechanisms in left hemisphere to receive info from other brain regions  If this communication is interrupted as in split brain patients, some kinds of info can never reach consciousness IV. Hypnosis  A specific & unusual form of verbal control that apparently enables one to control another’s behaviour, thoughts & perceptions  Provides insights about the nature of consciousness  Has applications in medicine & psychotherapy  Modern phenomenon of hypnosis or mesmerism was discovered by Franz Anton Mesmer  Does not cure physical illnesses  No single way to induce hypnosis & responses depend on what hypnotist says Characteristics of Hypnosis  Person undergoing hypnosis can be in a variety of states: alert, tense, relaxed, exercising, etc.  Only essential feature is participant’s understanding that he or she is to be hypnotized  Hypnotized people are very suggestible  3 types of hypnotic suggestions: 1. Ideomotor suggestions suggests that a particular action will occur without awareness of voluntary action 2. Challenge suggestions suggest that the hypnotized person will be unable to perform a normally voluntary action 3. Cognitive suggestions suggest that the hypnotized person is undergoing distortions of sensory or cognitive experiences, such as not feeling pain  Post-hypnotic suggestibility- tendency of a person to perform a behaviour suggested by the hypnotist some time after the person has left the hypnotic state  Post-hypnotic amnesia- failure to remember what occurred during hypnosis; induced by suggestions made during hypnosis  Studies show that when changes in perception are induced through cognitive suggestions, changes occur in people’s verbal reports about their perceptions, not in their actual perceptions  The visual system continues to process sensory info during hypnotically induced blindness Theories of Hypnosis  Sociocognitive approach  Hypnotic behaviours are social actions that reflect what the hypnotized individual believes or expects to be characteristic of hypnotized trance  Hypnotized person willingly adopts a role & enacts the role according to certain rules  being hypnotized is similar to participating vicariously in a narrative  Similar to being engrossed when reading a novel or watching a movie  We experience genuine emotions even though the situation is not real  Dissociation approach  Consider hypnosis as a specialized state in which awareness & conscious control centers of the brain become isolated from those controlling behaviours V. Sleep  Universal behaviour characterized by an altered consciousness The Stages of Sleep  Sleep research takes place in sleep laboratories  Polygraph-most important instrument of sleep laboratories that record changes in physiological processes such as brain, activity, heart rate & breathing  Standard psychophysiological measures of sleep recorded & produced by polygraphs: 1. Electroencephalogram (EEG)- measurement & graphical presentation of the electrical activity of the brain (brain waves)  recorded by means of electrodes attached to the scalp 2. Electromyogram (EMG)- measurement & graphical presentation of the electrical activity of muscle cells  recorded by means of electrodes attached to skin above them 3. Electrocardiogram (EKG)- measurement & graphical presentation of the electrical activity of the heart  recorded by means of electrodes attached to the skin 4. Electro-oculogram (EOG)- measurement & graphical presentation of the electrical activity caused by movements of the eye  recorded by means of electrodes attached to the skin adjacent to the eye  wires connected to the electrodes are plugged into amplifiers of the polygraph  a pen on the polygraph moves up & down on a continuous sheet of paper recording the output of each amplifier  EEG record distinguishes between alert & relaxed wakefulness  Cycle through initial stage 1 to stage 2,3, 4 of sleep  Beta activity- In a state of alertness or arousal, the EEG record shows irregular high-frequency, low amplitude electrical activity (polygraph pen does not move ve
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