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Department
Psychology
Course
PS260
Professor
Anneke Olthof
Semester
Fall

Description
Better retrieval • Chapter 1 • The scope of cognitive psychology • A brief history • Introspection • Behaviourism • Cognitive revolution • Research in cognitive psychology • Working memory • The Scope of Cognitive Psychology • - One way that we can define cognitive psychology is as the study of knowledge How do we study and memorize? How do we focus our attention and concentrate? How do we make decisions? • However, a much larger range of our thoughts, actions, and feelings depend on knowledge Understanding a story or conversation depends on knowledge the reader already has “Betsy wanted to bring Jacob a present. She shook her piggy bank. It made no sound. She went to look for her mother.” • H.M., a patient with amnesia, provides additional examples of how thoughts, actions, and feelings depend on knowledge Without the ability to form new memories, H.M. could not grieve for an uncle who had died, always hearing the news as if for the first time Without memory, there is arguably no sense of self. H.M. had no sense of whether he was honourable or dishonest, industrious or lazy • A Brief History: Introspection • Wundt and his student Titchener began the study of experimental psychology in the late 1800's For the first time, it was a discipline separate from biology and philosophy. The focus was on conscious mental events • Introspection – the process through which one “looks within” to observe and record the contents of one’s own mental life Problems with Introspection: Much of mental activity is unconscious and not available to the method of introspection Claims derived from introspection are subjective and not testable • A Brief History: Behaviourism • The desire to be more scientific led to changes in psychology during the first half of the twentieth century The focus switched 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 with Behaviourism Behaviour cannot be understood only in terms of stimuli and responses. Behaviour also depends on things like perception, understanding, interpretation, and strategy Example: passing the salt Speech stimuli that are physically different from each other can result in the same response Please pass the salt Pass the salt please Do you have any salt? Speech stimuli that are physically identical to each other can result in different responses It is bad luck to say ‘pass the salt’ in a thunderstorm In both cases, it is the interpretation of meaning that determines the response • Cognitive Revolution • From introspection and behaviourism, experimental psychologists 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, but do so indirectly Visible events are measured, such as stimuli and values to figure out how a crime was committed Or to a physicist studying electrons, which cannot be directly seen • Research in Cognitive Psychology: Working Memory • Working memory is the storage system in which information is held while it is currently being worked on We will use working memory as an example of how research in cognitive psychology works • The span test is used to determine the holding capacity of working memory. We can use performance on the span test (a behaviour that can be measured) to make inferences about the underlying working-memory system (mental events) This is an example of the indirect study of mental events • The working-memory system is not a single entity In one view, a central executive coordinates the activities in other “assistant” components One assistant is the articulatory rehearsal loop The articulatory rehearsal loop has two elements: Subvocalization – silently pronouncing words A phonological buffer – an auditory image of the words Evidence for the working- memory model During span tasks, confusions are often made between letters that sound alike, not letters that look alike This suggests that the working- memory system makes use of mechanisms that are used during speaking and hearing Concurrent articulation reduces memory span dramatically This suggests that the model needs to incorporate speech mechanisms Evidence from cognitive neuroscience is also brought into the model The testing of people with anarthria – the inability to produce overt speech – has shown that muscle movement is not needed for subvocal rehearsal Brain imaging suggests that the 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 Often a single piece of data can be explained by a variety of hypotheses Working memory is more than just the span task These mechanisms are important during reading, reasoning, and problem solving The rehearsal loop plays an important role during development as we are learning new vocabulary When we begin to understand a cognitive mechanism (like working memory) in simpler experimental situations (like the span task), 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 • The simplest fact illustrated by Capgras syndrome is that different parts of the brain perform different jobs • Researchers began to realize this in the 19th century by studying the cognition and behaviour of patients with lesions to the brain • Ex. Phineas Gage 1848; an explosion during the construction of a railway sent a tamping iron through his frontal lobes Resulted in a variety of cognitive and emotional changes Well respected man in the community, great reputation; after accident he couldn't make decisions very well, had no filter Animal instincts came out • Study of people with brain lesions also help us learn about the functions of these brain regions in healthy people • Referred to as localization of function • Even for seemingly simple cognitive tasks, multiple regions of the brain are involved • Ex. Pouring a glass of milk requires a lot of complex processes in the brain Three parts of the brain 1. Hindbrain • Sits directly atop spinal cord • Controls rhythms of the heart and breathing • Regulates levels of alertness • Includes the cerebellum Coordinates movements and balance + more recently discovered sensory and cognitive roles Damage results in difficulty handling spatial tasks such as finding a short route 2. Midbrain • Sits above hindbrain • Coordinates movement, especially eye movement • Includes parts of the auditory pathways • Regulates the experience of pain 3. Forebrain • Comprises most parts of the brain that are visible from the outer surface • Includes the cortex; a thin convoluted sheet of tissue • Avariety of subcortical structures Cortex is divided in to the left and right cerebral hemispheres by the longitudinal fissure Commissures, thick bundles of nerve fibers, connect two hemispheres Largest is the corpus callosum Cortex is divided into anterior and posterior regions Each hemisphere can be divided into four lobes Frontal lobes Motor areas, reasoning, etc. Parietal lobes Spatial processing, sense of touch, etc. Temporal lobes Hearing Occipital lobes Vision Subcortical parts of forebrain Thalamus Hypothalamus Under thalamus Motivated behaviours; sex, food, drink, sleep Limbic system Amygdala Processes emotion Hippocampus Important in formation of new memories - Recall that neuroimaging allows researchers to take high quality, 3D images of the living brain • Computerized axial tomography (CT) • Takes x-rays 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 paint detailed picture of someone's brain • Functional magnetic resonance imaging (fMRI) • Allows us to see where certain activity is happening • Example of fMRI study 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 the activation level in these two regions reflects what the person is conscious of, not just the presented visual stimuli • Regions indicated by fMRI studies are not always necessary for task in question May be only correlated with the task, in the way a speedometer is correlated with the movement of a car Another technique known as 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 the association cortex • PMPA is located in the posterior frontal lobes • More cortical space is devoted to 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 gets • Primary somatosensory projection area is located in the anterior parietal lobes • Primary auditory projection area is located in the superior temporal lobes • Primary visual projection area is located in the occipital lobes - Cortical maps represent sensory or motor 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 eye ⁃ - Cortical organization is contralateral Neurological Syndromes 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 pays 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 an excellent illustration of how the close study of brain and proceed and what it can teach us 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 neural tissue; three layers of neural tissue • First layer is photoreceptors Two types of photoreceptors, or cells that respond to light, are found on the retina Rods Higher sensitivity Lower acuity Colour-blind Found in the periphery of the retina Sensitive to light Cannot pick out visual details well Ex.Ability to see stars Cones Lower sensitivity Alot of light has to hit cones to go off Higher acuity Very detailed Colour sensitive Found in the fovea Middle of 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 info 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 the occipital lobe • Visual 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: Cell C is more inhibited than Cell B Cell A, B and C look at bright stimulus; get a lot of input coming into cells More input coming into cell, more to send on to neighbours Cell D, E and F doesn't get as much input; cannot laterally inhibit neighbours as much as A, B and C Cell B would not be as inhibited if it wasn't for cellAand C Cell C is getting a lot of inhibition from B, but cell D is sending more because it doesn’t have as much inhibition as cell B • Much of what we know about visual system comes from technique known as single-cell recording Neurons are crucial to SCR Communication between neurons is done via chemical signals Neurotransmitters are chemicals released by neuron to communicate with another neuron Space between two is called synapse First neuron is called presynaptic neuron, second is called postsynaptic neuron Communications within neurons is done via electrical signals Neurotransmitters affect postsynaptic neuron by changing ion distributions and resulting electrical potentials If postsynaptic cell reaches threshold, an action potential is fired and propagates down the axon, releasing neurotransmitter that affects the next neuron Aneuron's firing rate of frequency of action potentials is reached as various kinds of visual stimuli are presented to the subject Using these methods, researchers map out receptive field for various cells of visual system Receptive field: The kinds of stimuli to which the neuron best responds Receptive fields of bipolar cells, ganglion cells and cells in lateral nucleus have a center- surround organization 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 Example of parallel processing Asystem in which many different steps or kinds of analysis occur at the same time Another example is found earlier in visual pathway in ganglion cells, optic nerve and LGN 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 Also demonstrated by higher visual pathways From area V1, info is sent to many secondary cortical visual areas for future parallel processing Opposite of parallel processing is serial processing Steps carried out one of a time Secondary visual systems What system Concerned with the identification of objects Involves an 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 in occipital-parietal pathway Damage to this system can result in problems reaching for objects Parallel processing splits up problem -> we do not see the world disjointed -> binding problem Elements that help solve the 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 Conjunction errors: Correctly detecting the features present on a visual display but making errors regarding how the features are bound together • Our account of vision requires both lower-level activities: E.g. what happens in individual neurons and the synaptic connections between them • 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 20th 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 • Alater stage in which perception goes “beyond the information given” • However, this view presumes serial processing, not the parallel processing that characterizes the visual system • Our interpretation of the visual input influences how basic visual features are processed • Until interpretation is given to something, we cannot understand it • Examples given illustrate that the brain areas that analyze the basic visual features and the brain areas that analyze large-scale form are interactive, each sending information to the other • Example of parallel processing Bottom top and top down processes working simultaneously • Means that we we see is not just determined by the stimuli in front of our eyes, but also the brains interpretation of that stimulus The perceptual system operates as if it were gathering hypotheses about what objects are being perceived, given the available data Our visual system looks for the simplest understanding, avoiding interpretations that involve coincidences • Object recognition: The process through which the object is identified • Alot of our knowledge is based on our ability to recognize objects • First consideration about object recognition is that we can recognize objects when the information is incomplete E.g.Acat behind a tree is recognized even if only the head and one paw can be seen • The context in which objects are viewed can also have a large effect • Recognition might begin with the input pattern'sfeatures • Small elements out of which more complicated patterns are composed • Advantages of a features-based system Features could serve as building blocks, allowing a single object-recognition system to deal with a variety of targets Focusing on features might allow us to concentrate on what is common to otherwise variable objects Experimental tasks such as visual search suggest that features do have priority in perception Other data suggests that the detection of features is a distinct step in object recognition Adisorder called integrative agnosia, caused by parietal cortex damage, involves a preserved ability to detect whether certain features are present in a display but a disrupted ability to judge how features are bound together in objects Asimilar dissociation has been produced using TMS (transcranial magnetic stimulation) Some methodology for studying word recognition: The tachistoscope is a device for presenting stimuli for precisely controlled amounts of time Today, computers are used for this purpose • Word stimuli may be followed by a mask (a stimulus designed to disrupt further sensory processing of the words) such as a random string of letters • Visual words can be recognized with extremely brief presentations under the right conditions: • Words that are more frequent in the language are better recognized • Words that have been recently seen are better recognized Known as repetition priming • Words in general are better recognized compared to strings of letters • Known as word-superiority effect • In an experiment demonstrating the word-superiority effect, a procedure known as two- alternative forced choice might be used • Ex. A word such as “DARK” is briefly presented and the participant is asked whether an “E” or a “K” was present in the display • Participants are more accurate when the letters appear within a word than when they are by themselves as single letters • Feature nets • One possibility for how the visual system recognizes words is through a system called a feature net The initial layer, at the bottom, comprises detectors for features Ex. “CLOCK” (word detector) -> C.L.O.C.K (letter detectors) -> curves of letters (feature detectors) Subsequent layers detect more complex patterns like letters, and then words There are similarities to how neurons fire and send information to each other The detectors have receptive fields, they fire a signal when a threshold of stimulation is reached However, the detectors here are probably not individual neurons, but more complex assemblies if neurons Signal continues on to next step of processing (from feature detectors to letter detectors) • Feature net can explain two of the experimental results discussed earlier: • Words that are more frequent in the language are better recognized • Words that have been recently seen are better recognized (repetition priming) • In both of these situations, detectors that have fired more recently have a higher starting activation level • To explain the word-superiority effect, the finding that words in general are better recognized compared to strings of letters, we must add another layer to the network that detects bigrams (letter pairs) • Ex. “CLOCK” = “CL” “LO” “CK” = C.L.O.C.K = curves of letters Word detector, bigram detector, letter detector, feature detector • Bigram layer also helps the system recover from confusion about individual letters A similar mechanism explains why an ambiguous stimulus can be perceived as an “A” in some contexts and an “H” in others • One downside to this organization is that it leads to errors of over-regularization • Networks biases usually help achieve correct perception • Our visual system is more likely to go for the most obvious/likely answer • What the network “knows” about spelling, or what it “expects” or “infers” about the patterns it sees is not locally represented in any single detector, but rather is a property of the network as a whole • This is an example of distributed knowledge • Note that errors made by the network are produced by the same mechanisms responsible for its advantages • The ability to deal with ambiguous inputs and to recover from errors • The network sacrifices a small amount of accuracy for a great deal of efficiency • McClelland and Rumelhart's (1961) model of word recognition included two additions: • Excitatory and inhibitory connections between detectors Top-down connections from words to letters and letters to features • Similar feature nets may underlie our perception of objects • The recognition by components (RBC) model includes an intermediate layer that is sensitive to geons (basic shapes proposed as the building blocks for all 3-D forms) Only need 36 geons to form an object as conceivable • One piece of evidence supporting the representation of geons is that perceptually degraded pictures are better recognized if geons are preserved • Models of objects recognition differ on whether object recognition depends on viewpoint • In the recognition by components model, geons result in viewpoint- independent recognition • Other proposals are viewpoint-dependent, requiring the remembered representation to be “rotated” into alignment with the current view • Different Objects, Different Recognition Systems • Some evidence suggests that certain categories of objects are perceived using specialized mechanisms • In particular, the recognition of faces may involve principles different from those discussed thus far • One source of evidence for specialized face-processing mechanisms comes from prosopagnosia • Atype of agnosia in which the visual object-recognition deficit is specific to faces • Perception and memory for faces is also highly viewpoint-dependent, much more so than for other objects • Inverting faces causes a greater disruption in memory performance compared to houses • Ex.Altered photographs illustrate how viewpoint-dependent the perception of faces is Upside down, two pictures do not look that different even though on is distorted If image was right side up, the difference would be more obvious • Prosopagnosia and strong viewpoint-dependent suggests that faces are processed with specialized mechanisms • Similar effects have been found for other categories when: Expertise is high (e.g. Dog judges) Specific individuals have to be recognized Configurations of component parts are important • Bottom-up (data-driven) processing • Perceptual information triggers a response in feature detectors • Top-down (concept-driven) processing • Broader patterns of knowledge and expectation trigger responses in complex pattern detectors • Complex pattern detectors in turn excite and inhibit feature detectors Models that include both bottom-up and top-down processing are known as interactive models Chapter 4:Attention • Selective attention: The skill through which one focuses on one input/task while ignoring other stimuli • Attention studies sometimes employ a task called employing Using headphones, different information is presented to each ear Known as dichotic listening • - The participant pays attention to information presented to one ear (the attended channel) while ignoring information presented to the other (unattended channel) • Results suggest that unusual characteristics of the unattended channel go unnoticed • Similar effects occur in visual studies Ex. Gorilla on the basketball court/counting passes video • - Some important exceptions, where certain pieces of information will be noticed even if presented to the unattended channel • The participants own name, any words of high personal significance will be noticed in unattended channel • - Pattern is observed in real life situations, sometimes called the cocktail party effect - Applies with things you associate with (e.g. Hometown, favourite sports team, etc.) • - Sometimes effects of attention are so strong that we fail to see stimuli right in front of our eyes • Ex. If participants are asked to look at a fixation target, while attending to another part of the screen, they may fail to notice changes in shape to the fixation target • Referred to as inattentional blindness E.g. When looking for an object, and is right in front of your eyes but you overlook it Studies suggest that there is “no perception without attention” Other studies suggest that unconscious perception still occurs in the absence of attention Ex. Participants judgements of line length are influenced by presence of “fins” that case the Muller-Lyer illusion, even if they do not conscious see the fins • - Other studies of attention focus on a phenomenon known as change blindness • The inability of observers to detect changes in scenes they are looking directly at • Similar effects of change blindness occur when people fail to notice continuity errors in films Ex. Participants in study failed to notice when the person asking them for directions changed identity (following a brief interruption by two people carrying a door) Our brain processes very little of what goes through our eyes 75% of people failed to notice that the person switched They're not sure why some people can pick this up and some can't They think that maybe it's just coincidence that the person who noticed may have just been focusing on one characteristic of the person by instance that changed with the appearance of person two • - Early studies of attention focused on when the perceiver selects the desired input • According to the early-selection hypothesis, the unattended input receives little to no analysis • According to the late-selection hypothesis, all inout receives analysis but only the attended input reaches consciousness or is remembered Both hypotheses capture part of the truth The study discussed earlier showing unattended stimuli effects on perception seems to be a case of late selection However, electrical activity of the brain for attended vs. Unattended inputs differs within 70 ms of stimulus presentation, suggesting early selection • - Selection depends on resources • Complex stimuli involve more effort, leading to early selection • Easy stimuli involves less effort, leading to late selection • - Selection as a form of priming • Lower threshold leads to easier recognition Attended channel has lower threshold Your name is frequent and is primed even when unattended • - An experiment by Posner and Snyder (1975) illustrates that there are two kinds of priming related to attention • One kind of priming is stimulus-based, the other expectation-based • For this type if study, the dependent variable is the response time to make a decision about stimuli • Posner and Snyder found in the low-validity condition that the primed condition was faster than neutral Demonstrates an effect of repetition priming; the receptors were “warmed up” • - The misled condition was not any slower than neutral • Warming up the wrong detector does not take activation away from the correct one • - Posner and Snyder found in the high-validity condition that the primed condition was much faster than the neutral • Demonstrates an additional effect of expectation in addition to repetition priming • - Further, the misled condition was slower than the neutral conditioned • Expectation is limited in capacity; the “wrong” expectation interferes with activating the correct detectors • - Studies of spatial attention examines the ability to focus on a particular position in space and to be prepared for stimuli appearing in that position • - Ex. When detecting a stimulus on the right or left side of the screen, participants benefit if an arrow provides a cue indicating on which side the stimulus is about to • - Spatial attention is sometimes thought of as a “searchlight” • We can move this searchlight in space, as well as adjust the size of the “beam” • Do we attend to positions in space or to objects? Evidence from unilateral neglect syndrome, caused by the damage to the right parietal lobe, could be argued to attend to space-based; individuals cannot see let side of drawing Some experiments suggest that the deficit is also object-based Ex. Unilateral-neglect patients attend to the red circle, initially presented on the right, even after it rotated to the left side of the object Healthy participants also show a mixture of spatial and object based attention • - Summary of selective attention • Attention involves both facilitating the processing of desired input and inhibiting the processing of unwanted input • Attention can be directed to both what the job is as well as where it is in space • There is some flexibility in where the effects of attention will take place (early/late) • What we think of as attention is not a single process or a particular mechanism • - Divided attention: Refers to the skill of performing multiple tasks simultaneously • Only possible when the sum of the tasks' demands is within the “cognitive budget” • Julius Caesar was praised for this ability to multitask • Some cognitive resources are specialized Verbal and spatial tasks can sometimes be performed simultaneously because each draws upon different resources • - Other cognitive resources are general • Ex. Speaking on a cell phone interferes with the ability to drive, even through the two tasks are seemingly very different • Several task-general cognitive resources have been proposed, such as: A response selector that is required for both selecting and initiating responses, both physical and mental A central executive that sets goals and priorities, chooses strategies, and directs thefunction of many cognitive processes Executive control is strongly connected with working memory Also believed to inhibit automatic or habitual responses when a situation requires a novel response Kane et al. (2001) found that individual differences in working memory did not predict the ability to move the eyes towards a cue (the automatic response), but did predict the ability to move the eyes away form a cue (a novel response) • - Prefrontal cortex is especially important to executive control • - As a task becomes more practiced, it requires fewer cognitive resources • As the ability becomes more automatic, executive control and the response selector are needed less and less • - Why does practice improve performance? • Complex tasks (playing tennis, playing the piano, driving a car) can by themselves create problems in divided attention • With practice, components of the task change from being controlled processes to being automatic ones Controlled tasks are novel and require flexibility in one's approach These tasks require attention and cannot be carried out if the person is busy with another task Automatic tasks are well practiced and do not require flexibility • These tasks require little or no attention and can be carried out if the person is also busy with another task • The downside of automaticity is seen in tasks that require the participant to override an automatic response • The Stroop task illustrates the high automaticity of reading (“RED” is coloured yellow, asked to say colour instead of word) • - Summary of divided attention and practice: • Tasks require resources, and cannot “spend” more resources than you have • Some resources are task-specific, and others are task-general • If two tasks make demands upon the same resources, the result will be interference • Practice increases the automaticity of a task, resulting in the need for fewer cognitive resources Chapter 5 Introduction - One way to frame learning and memory: - Acquisition - Storage - Retrieval -Analogy to creating (acquisition), storing (storage), and opening (retrieval) a computer file - Virtually all mental activities require working memory (WM) - Reading - Goal-driven behaviour - Some tasks demand more WM resources than others - Individual differences in WM capacity predict some cognitive abilitiesWorking Memory - Digit-span task:Used to determine an individual’s working memory capacity - Participant hears a series of digits and repeats them back - The longest list length that can be reliably repeated back by the participant is his or her digit span - Working memory capacity is typically 7 plus-or-minus 2 (Miller, 1956) - Chunking refers to a repackaging of the information held in working memory - Aseries of letters HOPTRASLU can be chunked as the syllables HOP, TRA, SLU - Working memory can hold 7 +/- 2 chunks of information - Effort and attentional resources are required to repackage the input - Does not increase the size of working memory itself - One metaphor for working memory is a loading dock - Mechanically transfers input to and from long-term memory - Abetter metaphor is a librarian - Actively categorizes, catalogs, and cross-references new material - Reading span: Ameasure that captures the active nature of working memory - Participant reads a series of sentences and must remember the last word in each sentence - The number of sentence-final words that can be remembered is the operation span - Operation span:Another measure that captures the active nature of working memory - Participant determines whether an equation is true or false, and must remember a word paired with each equation - The number of words that can be remembered determines the operation span - Reading span and Operation Span correlate more strongly with test performance, reasoning, and reading ability than does the digit span - Working memory is often divided into three components: 1. Central executive – makes decisions, plans responses, and coordinates helper components 2. Visuospatial buffer – helper component that deals with visual material and imagery 3. Articulatory rehearsal loop – helper component that deals with verbal material - Executive control refers to processes that are needed to: - Control the sequences of our thought and action - Select and launch responses - Plan and set goals - Resist falling into habit or routine - The modal model continues to explain basic contrasts between WM and LTM: - WM stores information currently being thought about; LTM stores all information one knows - WM limited in capacity; LTM great in capacity - WM easily loaded and accessed; LTM less easily - WM fragile and easily displaced; LTM more enduring Entering Long Term Storage - Two Types of Rehearsal - Maintenance rehearsal – thinking about the material in a rote, mechanical way; repetition - Relational or elaborative rehearsal – thinking about the material in terms of meaning, relating the items to each other and to what one already knows - Relational or elaborative rehearsal is superior to maintenance rehearsal for establishing information in LTM - Even repeated exposure to information does not guarantee encoding in LTM - E.g., try to remember the design details of a penny - If we compare the brain activity for remembered and forgotten items at the time of encoding, activity in the hippocampus and prefrontal cortex predicts later retention - Shallow processing – engaging the information in a relatively superficial way - E.g., making a decision about a typeface - Deep processing – engaging the information in a more meaningful way - E.g., thinking about meaning - Deeper processing ensures better recall - Incidental learning – learning in the absence of any intention to learn - Intentional learning – learning with the intention to learn - Imagine an experiment in which cross depth of processing (3 levels) - Typeface task (shallow) - Phonological task (intermediate) - Semantic task (deep) - And intention to learn (2 levels) - Incidental learning - Intentional learning - Depth of processing has a strong effect - Compare rows of table - Intention to learn does not have a measurable effect - Compare columns of table -Any effects of intention to learn are indirect; it all depends on whether the participant chooses a deep-processing strategyElaborate Encoding - Depth of processing promotes recall by facilitating later retrieval - Cataloguing a book doesn’t ground it more firmly in the building but makes it easier to find later - Depth of processing promotes recall by facilitating later retrieval - Consider learning as a way to establish indexing, a path to the information - Connections between to-be- remembered items facilitates retrieval - Craik & Tulving (1975) showed that words appearing in more elaborate sentences: - “The great bird swooped down and carried off the struggling chicken ” - Were better remembered than the same words in simple sentences: - “She cooked the chicken ” - This benefit for words that were encoded in elaborate sentences may be the result of richer retrieval paths – paths that guide one’s thoughts towards the content to be remembered - Greater elaborative encoding creates more retrieval pathsOrganizing and Memorizing - Katona (1940) argued that the key to creating connections in the to-be-remembered material is organization - We memorize well when we find order in the material - Mnemonics are strategies used to improve memory by providing an organizational framework - The downside is not finding a richer understanding of the material by relating it to things already known - Peg-word systems : items are “hung” on a system of already well known “pegs” - “One is a bun, two is a shoe…” - First- letter mnemonics - Roy G. Biv - King Phillip Crossed the Ocean to Find Gold and Silver - Mnemonics help recall -Ambiguous passages are understood and remembered better if they are given a clarifying title (Bransford & Johnson, 1972)- Ambiguous pictures are understood and remembered better if they are identified (Wiseman & Neisser, 1974) - Memory for digits is enhanced if patterns can be discoveredLinks AmongAcquisition, Storage, and Retrieval - Memory is facilitated by organizing and understanding the materials, not by mere exposure - What the memorizer was doing at the time of exposure matters - The background knowledge of the memorizer matters -Acquisition, storage, and retrieval are not easily separable: - New learning is grounded in previously learned (stored) knowledge - Effective learning depends on how the information will be later retrievedChapter 6Learning as Preparation for Retrieval - Recall that when we learn, we make connections between the newly acquired material and representations already in memory - These connections serve as retrieval paths when we need to remember the new material. - Context-dependent learning – new material is most likely to be recalled when the person is in the same mental, emotional, or biological state as when the material was learned. - For example, materials learned while on land are best recalled while on land, and materials learned while underwater are best recalled while underwater - Context reinstatement , or recreating the context that was present during learning, will improve memory performance - Fisher & Craik (1977) presented participants with word pairs and asked them to remember the second word; the first word served as context - The word pairs were either semantically related or rhymed - During testing, the prime words were presented as cues or hints - Two effects were observed: - Depth of processing effect – thinking about meaning at the time of encoding provides an advantage, compared to thinking about rhyming at encoding - Context reinstatement effect – having the same kind of context during learning and retrieval provides an advantage, compared to different kinds of contexts. Encoding Specificity - Encoding specificity refers to the tendency, when memorizing, to place in memory both the materials to be learned as well as the context of those materials. - “The man lifted the piano.” [context: heavy] - “The man tuned the piano.” [context: music] -As a result, materials will be recognized as familiar later on only if they appear again in a similar context. - Encoding specificity also explains why memory for having seen an ambiguous figure depends on the interpretation being the same at encoding and retrieval. The Memory Network - Spreading activation travels from one node to another via the associative links - Similar to neurons - Input sums to reach a threshold, causing firing - We have seen this notion of networks and spreading activation earlier in the course in our discussion of feature nets - Networks suggest an explanation for why hints help us remember- State- dependent learning and content reinstatement - Different Forms of Memory Testing- Recall – the participant must generate the studied items, often in response to a contextual cue - “What was the name of the restaurant that we went to?” - Recall requires a search through memory and depends heavily on whether retrieval paths are available - Recognition – the studied items are presented to the participant, who decides whether they were encountered before - “Is this the name of the restaurant?” - If source memory is available, recognition responses are similar in mechanism to recall - “Yes, I saw this word before.” - In other cases, recognition responses are based on a feeling of familiarity. - “This feels familiar, so I must have seen it recently.” - Source memory and familiarity are also distinguishable neuroanatomically. - Participants are asked to make “remember/know” decisions, pressing one button if they recall the episode of encountering a particular item (“remember”) and another if they have a feeling of familiarity (“know”) - Activation in the rhinal cortex during encoding predicts later feelings of familiarity and a “know” response. - Activation in the hippocampus during encoding predicts later source memory and a “remember” response. Implicit Memory - Other ways of testing memory are more indirect. - We can expose participants to an event, later re-expose them to the same event, and assess whether the responses on the second encounter is different from those on the first - For example, the lexical-decision task can be used in such an experiment to demonstrate repetition priming – more efficient processing for repeated presentation of the same stimulus - This is observed even if the participant does not remember seeing the item before - Another example of repetition priming can be seen with word-stem completion. - Participants are given a string of letters and are asked to produce a word beginning with this string - E.g., “CLA-”; responses: “clam, class, or clatter” - If participants have encountered one of these words recently, they are more likely to provide it as a response in this task, even if they do not consciously remember seeing that word before - As another example of implicit memory, identification of these perceptually degraded images is easier if you have previously seen the intact images. - Results like these led to the distinction between two kinds of memory: - Explicit memory - Revealed by direct memory testing, such as recall or recognition. - Accompanied by the conviction that one is remembering a specific prior episode.- Implicit memory - Revealed by indirect memory testing, such as a priming task - No realization that one is being influenced by past experiences - “False Fame” Study by Jacoby et al. (1989) - Participants were first asked to read aloud a list of fictitious names - Some time later, they were asked to rate another list of names in terms of how famous each person was. - The list included real famous people, as well as fictitious names that had been read earlier - In some conditions, participants rated the fictitious names as famous - The familiarity of the name was misattributed - Illusion of Truth – an effect of implicit memory in which claims that are familiar end up seeming more plausible - In one study demonstrating an illusion of truth, participants first read a series of statements and were told that some of them were false - “Gail Logan says that crocodiles sleep with their eyes open.” - Later, participants saw the sentences again and had to judge whether they were true. - Statements that were heard before – even those that had been labeled as false – were later judged to be more credible than sentences never heard before - Another misattribution of a familiarity effect can be observed in frequently misspelled words. - Source confusion – where a bit of information was learned or where a particular stimulus was last encountered is misremembered - Eyewitness may select someone from a photo lineup based only on familiarity. Theoretical Treatments of Implicit Memory - In all of these cases we have seen people being influenced by memories that they are not aware of - In some cases, participants realize that a stimulus is familiar but have no memory of the encounter that produced the familiarity - In other cases, they do not even have the sense of familiarity, but they are nevertheless still influenced by the previous encounter with the stimulus. - One way to think about implicit memory is in terms of processing fluency - processing fluency – an improvement in the speed or ease of processing that results from prior practice in using those same processing steps - For instance, just as seeing a stimulus raises the activation level of the relevant detectors, perceiving a word or thinking about its meaning leads to a similar pre- activation or fluency in the relevant cognitive mechanisms - Processing fluency may underlie the feeling of familiarity for stimuli that we have previously encountered - There are many forms of implicit memory Amnesia - The distinction between explicit and implicit memory is also supported by evidence from cases of brain damage- Amnesia is a disruption of memory due to brain damage. - Retrograde amnesia is an inability to remember events that occurred before the event that triggered the memory disruption - Anterograde amnesia is an inability to remember experiences after the event that triggered the memory disruption. - Case study - The person known as H.M. was one of the most studied patients with amnesia -As a last resort in treating H.M.’s case of epilepsy, portions of the brain that caused the seizures were surgically removed -Afterward, H.M. had a severe anterograde amnesia and was unable to recall anything that took place after his surgery, as if nothing could get into long- term memory - Asimilar form of anterograde amnesia is observed in people with Korsakoff’s syndrome - This disorder is caused by a deficiency of thiamine (vitamin B1) in the diet and is associated with alcoholism. - Both H.M. and patients with Korsakoff’s syndrome have damage to the hippocampus and surrounding brain regions - However, note that damage to the hippocampus does not disrupt memories that are already established - Instead, the hippocampus is important for memory acquisition, or creating new memories - Cases of amnesia support the distinction between explicit and implicit memory. - Anterograde amnesia seems to be limited to explicit memory, while implicit memory is preserved - For instance, in 1911 Swiss neurologist Édouard Claparède performed an informal experiment with a Korsakoff-syndrome patient - When introducing himself to the patient, he hid a pin in his hand, which pricked the patient - Later, the patient could not explicitly remember Claparède but refused to shake his hand, vaguely saying “sometimes pins are hidden in people’s hands.” - Other examples of amnesic patients demonstrating preserved implicit memories: - Knowing the answer to a trivia question the second time around, even though not remembering being asked it before and given the answer - Preferring a musical melody that they had been exposed to before, even though not remembering having heard it before - People with anterograde amnesia also demonstrate improvements in procedural learning, which is another kind of implicit memory. - The patients we have been discussing demonstrate a dissociation between impaired explicit memory and preserved implicit memory. - What about the reverse dissociation, cases of impaired implicit memory and preserved explicit memory? - Collectively, finding data supporting both dissociations in two groups of patients would constitute a double dissociation. - Adouble dissociation between explicit and implicit memory (Bechara et al., 1995): - One patient had damage to the hippocampus but an intact amygdala, while the other patient had damage to the amygdala and an intact hippocampus - In the experiment, a blue light was followed by a loud boat horn, while other colours were not - The learned association between the blue light and the horn was probed both explicitly (with a question) and implicitly (by looking at conditioned fear) - Hippocampus damage disrupted the ability to report explicitly which light was associated with the horn, but this patient still demonstrated an implicit fear response to the blue light - Amygdala damage disrupted the implicit fear response to the blue light, but this patient could still report explicitly which light was associated with the horn - The data from amnesia echo an earlier point about the relationship between learning and memory retrieval - The nature of a disruption in the acquisition of new memories, depends on how the memories will be used or retrieved later on - What you are learning about memory is relevant for how to memorize the material in this course -At one level, you may want to learn the material in a manner that prepares you for the form of retrieval that is required for your exams - To make memory even stronger, the best strategy is to employ multiple perspectives, creating multiple retrieval paths for the material you want to learn Chapter 7 Introduction • Consider some of the errors that can arise when people try to remember episodes that are related to other things they know and have experienced • Also consider some factors that are directly pertinent to memory as it functions in day- to-day life • Memory Errors • Ex. of memory error Researchers interviewed nearly 200 people inAmsterdam several months after plane crash in city When asked if they had seen footage on television, over half of the participants reported they had No such film exists In follow-ups, many participants confidently provided details about crash • Similar effects are observed under experimental conditions Brewer & Treyens (1981) Found that participants who had been asked to wait in office recalled seeing books and other items typical of an office even though these items had not been present Associated "academic office" with "books" • Hypothesis regarding memory errors Memory connections link each bit of knowledge in memory to other bits of knowledge There are no clear boundaries separating the contents of one memory from others This organization plays a helpful role during memory retrieval However, it can be difficult to separate memory for a particular episode with associated knowledge in memory More connections lead to the spilling over of memories onto each other Boundaries become less distinct This observation of intrusion errors supports this hypothesis Intrusion errors: Errors in which knowledge intrudes into the remembered event Ex. When reading a story we may believe that propositions we inferred while reading the story were actually presented in the story itself Better memory, more intrusions in theme condition Worse memory, fewer intrusions in the neutral condition In the theme condition, a brief prologue set the theme for the passage that was to be remembered Inferred propositions allow room to make assumptions/add details The Deese-Roediger-McDermott (DRM) procedure is also used to demonstrate intrusion errors If a list such as "bed, rest, awake, tired, dream, wake, snooze..." is presented, participants are very likely to recall having studied the word "sleep" even though it was not on the list Other intrusions are due to schematic knowledge Schema: Refers to knowledge that describes what is typical or frequent in a given situation Ex. Schema for what goes in a toolbox, what happens when you go to the dentist, etc. If something goes against schema, we are more likely to remember it Schemata can help us when remembering an event Ex. The last time you went to a restaurant Schema of a restaurant includes script of events that typically occur (e.g. being given a menu) General knowledge may be helpful in reconstructing memory of this particular event Schemata can also cause us to make errors when remembering an event Ex. Imagine that you visit a dentist office where there are no magazines in the waiting area Your schema of a dentist office probably does include a waiting room with magazines This general knowledge may cause you to regularize your memory of this particular event and "remember" magazines that were not there Classic demonstration of the effects of schemata on memory was provided by Fredrick Bartlett (1932) Stories taken from NativeAmerican folklore were presented to British participants The gists of the stories were recalled correctly, but details were altered in memory Details that did not make sense from British perspective were left out or supplemented to make story fit better with the participants background knowledge/schemata The regularization of memories by schemata may explain the other memory errors we have discussed Book are remembered in an office because books are part of our schematic knowledge of offices Footage of a plane crash is remembered because major news events are learned about through such footage on television Memory connections are good and bad Good: Link related ideas/memories Bad: Makes us remember things that weren't there, make us envision things that never happened (plane crash) Another line of research has investigated the misinformation effect The participant experiences an event and is exposed to misleading information about how it unfolded Some time is allowed to pass On a later memory test, a substantial number of participants have incorporated the misleading information into their memory One study, participants viewed a series of slides, depicting a car accident Participants were asked "How fast were the cars going when they ___ each other?" Blank was filled in with words like "smash" "collided" "bumped" "hit" etc. Depending on word choice, influenced memory of crime "Smashed" = more likely to say broken class, say higher speed Other studies have shown that false autobiographical memories have been planted In certain cases, entire events can be planted into someone's memory, so that the person recalls - confidently and in detail - an event that never took place Ex. Having been hospitalized over night, spilled a bowl of punch at a wedding, etc. Study Researchers asked participants about events that happened in their childhood that they got from parents Some events actually happened, but some were made up 25% of participants recalled fake events in detail • Avoiding Memory Errors Other studies have demonstrated cases in which memories were surprisingly accurate What factors determine whether a memory will be accurate or subject to errors? Information that comes after event that clouds memory Experience event then something similar happens; get events mixed up Ex. You do something and your friend does something and they explain it to you so well that you think you were there or did it Amajor factor is the retention interval Retention interval: The amount of time that elapsed between initial learning and subsequent retrieval When an increased retention interval, more of the original event is forgotten and ha to be reconstructed with schematic knowledge This creates the source monitoring – which parts of the memory actually occurred and which parts are associated knowledge Three hypotheses for why memories weaken with time: Decay: Memories may fade or erode Interference: Newer learning may disrupt older memories Ex. of interference Baddeley and Hitch (1977) Found that the number of intervening games, and not the passage of time, predicted whether rugby players remembered the names of other teams Retrieval failure: The memory is intact but cannot be accessed Over time, change in perspective may make it harder to tap into retrieval cues There is some truth to all three hypotheses Aconcept related to interference is destructive updating Destructive updating: When new learning on a topic replaces old knowledge in memory, so that the old information is destroyed by newer input Contrary to popular belief, hypnosis does not help recover lost memories Hypnosis does make people more open to suggestion and more vulnerable to misinformation effect Instead, the method of recovering "lost" memories that is most grounded in research is to provide a diverse set of retrieval cues Ex. Context reinstatement, visualization This is because at least some forgetting is the result of retrieval failure, and this kind of forgetting can be undone However, these techniques cannot help someone recall details that were not noticed in the first place Memory confidence Research suggests that there is little relationships between our confidence in our memories This has been tested using the Deese-Roediger-McDermott (DRM) procedure as well as the misinformation paradigm discussed earlier Emotion and memory False memories can be just as emotional as memories for real events Thus, the degree of emotion experienced with a memory also cannot be used to detect false memories The feelings of "remembering" and "knowing" This distinction from Chapter 6 may provide some limited means for distinguishing real and false memories The feeling of "remembering" is more likely with real memories, whereas false memories may provide only a sense of familiarity or "knowing" However, this subjective distinction is a poor means for reliably discriminating real and false memories Summary of memory errors People sometimes confidently recall memories that never took place, in both the laboratory and real life These errors result from how memories for specific events are embedded in generalized schematic knowledge Schemata are normally helpful for remembering by providing organization and retrieval paths Forgetting may be a consequences of how our general knowledge is formed Specific episodes merge in memory to form schemata • Autobiographical memory • Autobiographical memory: Refers to memory of episodes in life • The self-reference effect is a tendency to have better memory for information relevant to oneself than for other sorts of material • The self-schema is a set of beliefs and memories about oneself • As before, memories about oneself are subject to errors Memories about ourselves are a mix of genuine recall and schema-based reconstruction Our autobiographical memories are also biased to emphasize consistency and positive traits Ex. 89% of students remember A's because it's consistent with self-schemata, only 29% remember the D's • Emotion and memory At a biological level, emotional events trigger a response in the amygdala that promotes consolidation Consolidation: The process through which memories are "cemented" in place through the creation of new or altered neural connections Amygdala will push memories to a more stable state if they are super emotional Several reasons why emotional memories are well remembered: Better consolidation Narrowing of attention More rehearsal Tend to play emotional things over and over in our head "What if" Flashbulb memories:Are memories of extraordinary clarity, typically for highly emotional events Are they accurate? Some flashbulb memories contain large-scale memories In one study, a group of college students were interviewed one day after the 1986 space shuttle Challenger explosion Five years later, confidence was high but there were many Other flashbulb memories are well remembered
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