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Midterm Review Oct. 2013 PS260 Cognitive Psych

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Wilfrid Laurier University
Anneke Olthof

PS260 Cognitive Psychology – Midterm Review Chapter 1: The Scope of Cognitive Psych – Example of research in cognitive psychological = Working memory – H.M. Example – Could not grieve for uncle who had died; always heard news as if for the first time – Shows that: – Without memory, there is no sense of self – Without memory, H.M. didn't know if he was lazy, ambitious, honourable, etc. – A Brief History: Introspection – Wundt + Thitchener = introduced experimental psych in 1800's – First time discipline separate from biology/philosophy – Focus on conscious mental events – Introspection: The process though which one “looks within” to observe and record contents of ones own mental life – Problems: – Much mental activity is unconscious/not available to method of introspection – Claims derived from introspection are subjective and not testable – A Brief History: Behaviourism th – Introduced first half of 20 century – Focus shifted to stimuli and behaviours that could be objectively studied – Introspection and other “mentalistic” approaches were avoided – Behaviourism: Uncovered principles of how behaviour changes in response to stimuli such as rewards and punishments – Problems: – Behaviour cannot be understood only in terms of stimuli and responses – Behaviour also depends on things like perception, understanding, interpretation and strategy – Ex. Passing the salt – Speech stimuli that are physically different can result in same response – Pass the salt? Please pass the salt? Do you have any salt? – Speech stimuli that are physically identical can result in different responses – Bad luck to say “pass the salt” during a thunderstorm – In both cases, it is the interpretation of meaning that determines the response – A Brief History: Cognitive Revolution – From introspection and behaviourism, experimental researchers learned that: – Introspective methods for studying mental events are not scientific – However, we need to study mental events in order to understand behaviour – Cognitive psychologists study mental events indirectly – Visible events are measured, such as stimuli and responses – Hypotheses are developed about the underlying mental events – Hypotheses are further investigated by designing experiments to gather further measurable events – Research in Cognitive Psych: Working Memory – Working memory: Storage system in which information is being held while it is currently being worked on – Span test: Used to determine the holding capacity of working memory – Can use performance on span test (behaviour that can be measured) to make inferences about underlying working memory system (mental events) – Example of indirect study of mental events – Working memory system is NOT a single entity – A central executive coordinates the activities in other “assistant components” – One assistant is the articulatory rehearsal loop – ARL has two elements: – Subvocalization: Silently pronouncing words – Phonological buffer: Auditory image of words – Evidence of working memory model – During span tasks, confusions are often made between letters that sound alike, not letters that look alike – Suggests that working memory system makes use of mechanisms that are used during speaking and hearing – Concurrent articulation: Reduces memory span dramatically – Suggests that model needs to incorporate speech mechanisms – Evidence from cognitive neuroscience is also brought into model – Testing of people with anarthia has shown that muscle movement is not necessary/needed for subvocal rehearsal – Anarthia: The inability to produce overt speech – Brain imaging suggests that same regions used for subvocal rehearsal are used during speech production and comprehension – Multiple lines of evidence must be used when hypothesizing mechanisms used to explain observable data – A single piece of data can often be explained by multiple hypotheses – Working memory is more than just span test – Mechanisms are important during reading, reasoning and problem solving – Rehearsal loop plays important roll in development as we learn new vocabulary – Conclusion – When we begin to understand a cognitive mechanism (working memory) in simpler experimental situations (span test), we begin to understand all of the broader contexts in which the mechanism plays a role Chapter 2: The Brain – The Principle Structures of the Brain – Capgras Syndrome – Illustrates how different parts of the brain perform different jobs – Researchers found this in the 19 century by studying cognition and behaviour of patients with lesions to the brain – Phineas Gage – Metal rod through frontal lobe; variety of cognitive and emotional changes – Localization of Function – The study of people with brain lesions helps us learn about the functions of these brain regions in healthy people – Referred to as the localization of function – Even for seemingly simple cognitive tasks, multiple parts of the brain are involved – Brain: three principle regions – Hindbrain – Sits directly atop the spinal cord – Controls rhythms of the heart/breathing – Regulates level of alertness – Includes the cerebellum (coordinates movement/balance) in addition to more recently discovered sensory and cognitive roles – Midbrain – Sits above hindbrain – Coordinates movement, especially eye movement – Includes parts of the auditory pathways – Regulates experience of pain – Forebrain – Comprises most parts of the brain that are visible from outer surface – Includes the: – Cortex: A thin, convoluted sheet of tissue – A variety of subcortical structures – Divided into left and right cerebral hemispheres by the longitudinal fissure – Commissures: Thick bundle of nerve fibres that connect the two hemispheres; the largest is the corpus callosum – Cortex is divided into anterior and posterior regions by the central fissure – Subcortical parts of the forebrain include: – Thalamus – Hypothalamus – Under thalamus – Motivated behaviours; sex, food, drink, sleep – Limbic system – Amygdala – Processes emotion – Hippocampus – Important in formation of new memories – The Lobes – Frontal lobes – Motor areas, reasoning, etc. – Parietal lobes – Spatial processing, sense of touch, etc. – Temporal lobes – Hearing – Occipital lobes – Vision – Neuroimaging allows researchers to take high quality, three dimensional images of the living brain – Computerized axial tomography (CT) – Takes x-ray of brain – Good to look at brain structure; what is located where – Positron emission tomography (PET) – Inject someone with radioactive substance – When person works on task, blood is sent to brain to work on task – Good to look at where activity happens – Magnetic resonance imaging (MRI) – Magnets are used – Different parts of brain have different magnetic properties – Used to pain detailed picture of someone's brain – Functional magnetic resonance imaging (fMRI) – Allows to see where certain activity is happening – Ex. Tong et al., 1998 – When viewing images of faces, the fusiform face area (FFA) is active – When viewing images of houses, the parahippocampal place area (PPA) is active – Using binocular rivalry, Tong and colleagues showed that the activation level in these two regions reflects what the person is conscious of, not just the presented visual stimuli – Note that the regions indicated by fMRI studies are not always necessary for the task in question – Instead, may be correlated with the task, in the way a speedometer is correlated with (but not needed for) the movement of a car – Another technique is the transcranial magnetic stimulation (TMS) – Can be used to ask whether an area of the brain is necessary for the task – Primary projection areas: The arrival and departure points for information entering (sensory areas) and leaving (motor areas) the cortex – The rest of the cortex has traditionally been considered association cortex – PPA is located in the posterior frontal lobes – More cortical space is devoted the regions of the body we move with the greatest precision (tongue, lips, etc.) – The more you have to use a function, the more brain space it is allotted – Primary somatosensory projection area is located in the superior temporal lobes – Primary visual projection area is located in the occipital lobes – Cortical maps represent sensory or other information in an orderly manner – Organization is by region of the body, region in space or auditory frequency – Cortical space is assigned disproportionately – Greater sensory acuity or motor precision is associated with larger cortical representation – Whatever is most sensitive receives the most cortical space – Ex. Middle of the eye – Cortical organization is contralateral – Neurological syndromes that reflect damage to regions of the association cortex include: – Apraxia: Problems with initiation or organization of movement – Angosia: Problems with identifying similar objects – Aphasia: Problems with language – Neglect syndrome: Problems in which half of the visual world is ignored – Ex. Only pay attention to the left side of everything such as brushing teeth, brushing hair, etc. – Prefrontal damage: Problems with planning and implementing strategies, inhibiting behaviours – The Visual System – Vision is the modality through which much of our knowledge is acquired – Vision provides and excellent illustration of how the close study of the brain can proceed and what it can teach us – The Structure of the Eye – Designed to project a sharp image onto the retina; the light sensitive tissue that lines the back of the eye – Retina is a neural tissue – Three layers of neural tissue: 1. Photoreceptors – Two types of photoreceptors – Rods – Higher sensitivity – Lower acuity – Colour-blind – Found in the periphery of the retina – Sensitive to light – Cannot pick out visual detail well – Ex. Ability to see stars – Cones – Lower sensitivity – A lot of light has to hit cones to go off – Higher acuity – Very detailed – Colour sensitive – Found in the fovea; middle of the eye, when eye moves, image lands on fovea – Crispest image, detail rich – Blind spot occurs when leaves to go to brain – Series of neurons communicate information from retina to cortex – In the eye – Photoreceptors – Bipolar cells – Ganglion cells and the optic nerve – In the thalamus – Lateral geniculate nucleus (LGN) – In the cortex – Area V1; aka the primary visual projection area, or primary visual cortex – Located in occipital lobe – Processing and analysis begins in retina – Patterns of lateral inhibition between neighbouring cells of the retina leads to edge enhancement – Edges of things look brighter, better, clearer – Ex. Mach bands – Lateral inhibition – A stimulus affecting all three neurons, but which affects B strongest or first, can be sharpened if B sends lateral signals to neighbours A and C not to fire, thereby inhibiting them – Lateral inhibition is used in vision to sharpen signals to the brain – Much of what we know about the visual system comes from a technique known as single-cell recording – To understand this we need to look into neurons – Parts of a neuron – Dendrites – Detect incoming signals – Cell body – Contains nucleus and cellular machinery – Axon – Transmits signals to neurons – Communication between neurons is done via chemical signals – Neurotransmitters: Chemicals released by one neuron to communicate with another neuron – Synapse: The space between two neurons – First neuron is called presynaptic neuron, second is called post-synaptic neuron – Communication within neurons is done via electrical signals – Neurotransmitters affect post-synaptic neurons by changing ion distributions and resulting electrical potentials – If post-synaptic cell reaches threshold, an action potential is fired and propagates down the axon, releasing neurotransmitter that affects the next neuron – In single cell recording, a neuron's firing rate or frequency of action potential is reached as various kinds of visual stimuli are presented to the subject – Using these methods, researchers map out the receptive field for various cells of the visual system – Receptive field: The kinds of stimuli to which the neurons best respond – Receptive fields of bipolar cells, ganglion cells and cells in lateral nucleus have a centre- surround organization – Stimulus in centre leads to faster firing rates – Stimulus in surrounding area leads to slower firing rates – Receptive fields of V1 are lines of particular orientations – These cells are sometimes called edge detectors – Certain corners, movements, shapes, sizes, etc. – Neurons in V1 are each specialized for a particular type of analysis – Ex. of parallel processing – A system in which many different steps or kinds of analysis occur at the same time – Another example is found earlier in visual pathways in ganglion cells, optic nerve and LGN – Opposite of this is serial processing – Steps are carried out one at a time – Parvocellular cells: Have smaller receptive fields and tend to continue firing as long as the stimulus is present – Magnocellular cells: Have larger receptive fields and respond more strong to changes in stimulation – Better with depth, movement – Parallel processing is also demonstrated by higher visual pathways – From area V1, information is sent to many secondary cortical visual areas for future parallel processing – Secondary visual areas lead to two major processing streams; what systems and where systems – What systems – Concerned with the identification of objects – Involves and occipital-temporal pathway – Damage to this system can result in visual agnosia – Where system – Concerned with determining the location of objects and guiding our actions in response – Involves occipital-parietal pathway – Damage to this system can result in problems reaching for objects – Parallel processing splits up problem -> we do not see world as disjointed -> binding problem – Elements that help solve binding problem – Spatial position: Visual areas processing features like shape, colour and motion each know the spatial position of the object – Neural synchrony: Visual areas processing features of the same object in a synchronous rhythm with each other – Attention is also critical for the binding of visual features – When attention is overloaded people will make conjunction errors – Correctly detecting the features present on a visual display but making errors regarding how the features are bound together – Ex. Someone might be shown a red “t” and a blue “h” but recall seeing a blue “t” and red “h” – Our account of vision requires both lower-level activities – E.g. What happens in individual neurons and the synaptic connections between themselves – As well as higher-level activities – E.g. The influence of attention on neural activity Chapter 3: Perception, Recognition – How do we perceive and recognize objects? – Form perception: The process though which the basic shape and size of an object are seen – Begins with the detection of simple visual features – Our perception of the visual world goes beyond the information given – Early 20 century movement (Gestalt psychology) captured this idea as “the whole is different from the sum of its parts” – World is different than visual input (our interpretation is off of what actually is) – Ex. We see it as a stop motion film, when really it's completely like a smooth movie – Necker cube is an example of perception going “beyond the information given” – Two different perceptions of depth are possible, given the lines on the page – Stimulus input is the same, interpretation determines what we're looking at – Face-vase figure – Two interpretations are possible, each based on a different figure/ground organization – This again shows that perception goes “beyond the information given” – Examples might suggest that perception proceeds in two stages: – One where visual features are processed – A later stage in which perception goes “beyond the information gi
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