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McGill University
PSYC 213
Jelena Ristic

Cognition Ch.1- Introduction What is Cognition  Cognition has no precise definition o action and faculty of knowing  it’s about the processes + the different divisions of our mind  Folk psychology= a set of assumptions and theories based on everyday behaviours of ourselves and others  Cognitive concepts o Awareness- consciousness o Intelligence- quickness of understanding/ info/ sagacity o Intuition- immediate insight o Personal acquaintance- social knowledge o Recognition- categorizing what we’ve seen/ reviewing and revising o Skill- reasoning/ practice knowledge/ expertise o Understanding- judgment, decision-making/ comprehension Cognitive psychology and information-processing theory  Everyday we are thinking and processing info: attending/ comprehending/ remembering / problem-solving  Info-processing theory derived from basic coms theory (Shannon & Weaver) o sender: encodes a message o communication channel: delivers the message o receiver: decodes (translates) the message  info from a message is not solely determined by the signal itself but also the whole array of possible messages Information theory  = information reduces uncertainty in the mind of the receiver o the amount of info provided in a message is proportional + inversely related to he probability of that message occurring  the less likely a signal is, the more information it conveys  bit= “binary digit”/ an even that occurs in a situation with 2 equally likely outcomes provides one ‘bit’ of info o the number of bits go up when the number of alternatives to the events doubles o ex. in a game where one has to guess one’s number between 1-8, you only need 3 questions to answer it Early tests of info theory  (Merkel) people respond more slowly to less likely signals  i.e. response time increases when number of alternatives increase (slower to answer)  (Hick) “information is intimately concerned with response time” (RT)  (Hyman) study showing also that: o RT to frequent (infrequent) signals was reduced (longer) o RT was faster as the signal’s probability increases o Shows that RT is not determined just by signal but by the complexity of the situation too Information-processing limitations  1) the amount of time it takes info to be processed in the nervous system  2) the amount of visual info that a person can transmit has limits  3) NS has a capacity limitation too for the amount of into that it can take in at one given time o ex. the more info a visual signal conveys, the longer the RT o (Webster and Thompson) Study on auditory messages  pilot-to-tower communication  results: control tower operators can identify 2 different call signals but process 1 of 2 simultaneous word message  = dichotic listening  difficulty in dealing with 2 stimuli at once shows how we’re limited in the amount of info we take in o when info-processing capacity is loaded, studies show we select only some of the total info (usually messages with similar properties)  we are active selectors of information Models of information-processing  Broadbent’s filter model (theory of attention) o Based on the idea that info-processing is restricted by channel capacity (= the maximum amount of info that can be transmitted by an info-processing device) o The NS seen as a single channel with limited capacity channel to transmit messages  This is preceded by a filter/ selective device that only passes along some of the incoming information  selects on the basis of physical characteristics only (if for instance 2 info comes at the same time)  Preceding this is a capacity-free sensory buffer/ short-term memory store  (preceding this is the input channels) o Study showed where there was a difference in recall performance, it was deduced that it was because ears function as separate channels for info input  Different physical locations for 2 messages are stored first in the short-term memory + selective attention (the filter) determines which channel to recall first  Switching attention between ears require time  decays info  1st condition of recalling all items from one ear to the next = one switch of attention  BUT 2 condition of recalling items in order played in both ears= at least 3 switches of attention  Waugh and Norman’s Model of info-processing o Influenced by James’ insights on introspection= act of observing one’s own thoughts and feelings as they seem to oneself o Theory states when we’re stimulated with info, we experience primary memory= what we are aware of in the ‘immediately present moment’ (immediate/ short-term memory)  Allows us to remember our most recent experiences o These memories are quickly forgotten unless they are rehearsed  Once rehearsed it can enter your secondary memory= knowledge of mind after awareness (long-term memory) o These memory distinctions were based on introspective evidence, but experimental evidence came with the Brown-Peterson task  = a paradigm in which subjects are given a set of items and then a number. Subjects immediately begin counting backward by threes from the number. After a specific interval, subjects are asked to recall the original items  ex. hear “ B-Q-R” and then “107” and have to count backwards like “104, 98…” o then after a few seconds they’re asked to recall the initial letters o since they never rehearsed it, it was forgotten  As the number of interfering items increased, Ps ability to recall decreased Ecological validity  Lot of interest in making the stimulus meaningful  (Gibson) argued that stimuli used in info-processing experiments did not reflect those of the real world developed an ecological approach = a form of psychological inquiry that reflections conditions in the real world o believed that the meaning of objects and events can be perceived by affordances= potential functions/uses of stimuli in the real world  ex. stairs afford climbing, food affords eating o it is a theory of information pickup= process whereby we perceive info directly  learning becomes more attuned with our env.  (Neisser) argued against with the perceptual cycle= the process whereby our schema not only guides exploration of the world, but also is shaped by what it finds there o schema= our expectations concerning what we are likely to find as we explore the world  we possess a schema as perceivers  it is our cognitive model of the environment made over time o if we see something unusual (ex. a balcony tilting upwards), we automatically impose our expectation (that the balcony be square) leading us to exploration of the object o the OBJECT modifies the SCHEMA, which directs our EXPLORATION to better understand the object. o This model increases our rationality toward dealing with the env.  Lab-based vs. ecological-based research has paved way for cognitive ethology= a new research approach hat links real-world observations with lab-based investigations Metacognition and cognitive psychology  Metacognition= the knowledge people have about the way certain cognitive processes work; how accurately you can assess your own cognitive processes o Study of cognition seen as process of developing our metacognition o Matures the mind as we all o Formulate and test hypotheses about how the mind works o Thinking about thinking Range of cognitive psychology o Human experimental psychology  Memory / attention/ problem-solving/ language o Computer analogies and information-processing approach  Artificial intelligence  Computer simulations o Cognitive neuroscience  Brain damage and effects on cognition Ch. 2 – Cognitive Neuroscience  Cognitive neuroscience= cognitive psychology + neuroscience (simply) o Goal is to discover brain mechanisms that give rise to mental fnxns  Neuroscientists assume the mind is composed of modules= sections of the brain, each responsible for a particular cognitive operation The Brain as the Organ of the Mind  Gall & Spurzheim promoted phrenology= study of shape, size and protrusions of the cranium as a relation to mental abilities o Brain is sole organ of the mind/ basic intellectual traits are innately determined/ where there is variation in fnxn, there is for structure  Localization of function= attempt to discover correspondences between specific cognitive fnxns and specific parts of the brain, based on a strict one- to-one relationship o Franz: expert in ablation  Discovered activities aren’t due to independent parts of the brain, but the brain working as a whole  Later used Histology= microscopic analysis of tissue structure o Lashley: Brain mechanisms and intelligence  Law of mass action= learning and memory depend on the toal mass of brain tissue remaining rather than the properties of individual cells  Law of equipotentiality= even though some areas of the cortex may become specialized, within limits any part of an area can do the job of any other part of that area  Metaphor of an electric sign: depending on which bulbs are lit, different messages are displayed The relation between Mind and Brain  Consciousness vs. mind distinction o Consciousness= narrower concept/ what we are aware of at any time o Mind= broader concept/ INCLUDES consciousness + other processes  Brain as the ‘organ of the mind’?  Interactionism= mind and brain are separate substances that interact with and influence each other o Descartes  postulated pineal gland as site of interaction  Epiphenomenalism= ‘mind’ is a superfluous by-product of bodily fnxning o Mind has no causal role in determining behaviour o Analogy w/steam engine  see steam but don’t know about engine  Parallelism= ‘mind’ + brain are 2 aspects of the same reality /flow in parallel o Fechner mental events being correlated to brain events o Having one introspect at the same time recording events in brain: gives insight into those brain events  Isomorphism= mental events and neural events share the same structure o Gestalt theory= form or configuration Gestalt psycs ex. Kohler o Consciousness is not just one event after another, but a coherent whole o An experience + corresponding brain process share the same pattern o Diff between parallelism and iso iso more than point-to-point mental correspondences  Necker Cube different views of the lines when seen as whole  External stimulus is constant, but internal/ subjective experience is different  Suggested- Due to different cortical processes  Kohler’s specific hypothesis was rejected  Don’t need to decide mind/brain issue for discovering the brain (for now) Methods in Cognitive Neuroscience  Animal models o = indirect route to studying human brains o use of lesions and single/multiple unit recordings o big weakness in animal models= full understanding of another organism won’t lead to complete understanding of human brain  cross-species structure+ function limitations  homologous structures are difficult to identify  Behavioural studies o Combination of knowledge on normal sensory systems + precise stimulus presentation + response recording  Ex. (study) eye movement RT decreases as a fixated visual object on a screen is turned off before an eye target  Eye’s connection with SC (superior colliculus) o Brain injury studies (lesions)  Hard to collect evidence for localization of function  Broca’s aphasia= disability to produce speech due to damage in Broca’s area (left hemisphere)  His patient couldn’t speak but could understand him  Wernicke’s area= disability to understand speech due to damage in Wernicke’s area (left hemisphere)  Patients ramble words without any meaning  However, these iconic areas still cannot bear full explanations o Surgical intervention (Sperry)  Interhemispheric transfer= communication between the brain’s hemispheres is enabled largely due to corpus callosum  Initially worked with cats with split brain operation (severing the c.c.) o animal behaved as ‘if it had 2 separate brains’  showed that not only do both hemispheres have unique capabilities, but that together they provide a whole new unified state of consciousness  found that can’t simply divide left + right hemisphere functions  Sperry argued that consciousness is an emergent property= ‘’mind’ comes as a result of brain processes, but is not itself a component- meaning that the mind is not reducible to or predictable form other features of the brain  Once C does emerge, then it can have influence over lower-level functions = emergent causation  Mutual interaction between neural and mental events  Mind was seen as a supervenient= mental states may influence neuronal events while being influenced by them o Event-related Potentials (ERPs)  Earliest imaging technique= computed tomography (CT)  Detailed anatomical data  Magnetic resonance imagining (MRI)  Greatest with spatial resolution  Neither provide images for brain activity, only structures  Brain activation records provide sensory info pathways + response-related processes  ERP= electrical signals recorded form the brain that occur after the onset of a stimulus  Brain emits electrical signals, recorded by electrodes  Represented by wavelengths  Present P with different items, and record ERPs from each item  Problem: ERPs are good at recording activity, but not easy to determine the underlying cognitive processes o Positron Emission Tomography (PET)  Imaging technique where P is injected with a radioactive substance that mingles with the blood and circulates to the brain. A scanner is then used to detect the flow of blood to particular areas of the brain  Assumes that when a psych fnxn is engaged, then only those parts of the brain will be engaged/ needing more blood flow  Active parts of the brain use up O2 at a faster rate  Problem: limits to the amount of P’s radiation intake o Functional Magnetic Resonance Imagery (fMRI)  = a non-radioactive magnetic procedure for detecting the flow of oxygenated blood to various parts of the brain  taken over the method of PET  place P in a large magnetic field/ causes atoms in brain to become aligned with the magnetic field  changes of O2 in blood are thus picked up as alterations in the magnetic field = image of cortical activity  Ex. fMRI on reading- reveals brain areas active in language processing  wide indvl differences per P  View of the brain is no longer phrenological nor just localizatn  Marshall and Fink suggested that (to some extent) the interaction of different areas of the brain determine their function on a particular occasion  Neural correlates of cognitive functions overlap o Connectionist Models  Connectionism= theory that cognitive processes are regulated by complex systems consisting of a large number of interconnected elements  Recognized that information-processing level is independent of physiological explanational level  Based on models of neural networks= a system of connections between elements that models connections between neurons in the nervous system (interconnected neurons)  2 basic connectionist ideas:  info can be broken down into elementary units (neurons)  there are connections between these units  Connections have different strengths// network learns by modifying strength of connections  Hebb rule= theory that a connection between 2 neurons takes place only if both neurons are firing at approximately the same time cell A is near enough to excite cell B –repeatedly firing enough so that A’s efficieny is increased as 1 of the B cells fire  Another name for connectionist models= parallel distributed processing models:  Parallel processing= theory that many neural connections can be active at the same time  Serial processing= theory that only 1 neural activity can take place at any time  Big difference between connectionism and older info- processing approaches= knowledge is in the connections that make up our network (vs. a series of info-processing stages)  Summary points o Static imagining techniques= CT + MRI o Dynamic imaging techniques= ERP, PET, fMRI  Generally dynamic techniques/ functional neuroimaging studies give not only images of brain structure but also activity of cognitive functions  However we only focus on single cognitive functions, rather than capturing the overlaps Ch.3- Perception  3 examples of why perception is a fascinating phenomena o illusion of clarity  a pixelated photograph without a grid is harder to make out than one with a grid  normally expect grid to interfere with the image more o visual agnosia= a deficiency in the ability to recognize visual info despite being able to see it  due to brain damage (can see but not id)  associative agnosia= a form of visual agnosia marked by a difficulty naming objects  sometimes they guess right: visual recognition isn’t always impaired o time spaces= perceptual experience of time units (ex. day/ months) as occupying spatial locations outside of the body  ex. one patient, months are experienced in an oval form  usually occur unconsciously  perception= processing sensory info such that it produces meaningful understating of the info o perception depends on both the  external environment =the stimulus= an entity in the external env that can be perceived by the observer  internal knowledge of the observer Perception as a Function of the Environment  Gibson’s theory of ecological optics= the proposal that perception involved directly absorbing the visual information present in the environment o Extreme view that perception is a fnxn of the environment o Perception is accomplished through the senses (sensory organs) most  Ex. the ambient optical array (AOA)= all the visual info that is present at a particular point of view  We get a different view of light from each viewpoint of the light,  Ex. texture gradients= gradual changes in the pattern of a surface that is normally assumed to be uniform, which provides info about surface characteristics such as whether the surface is receding or curved  When two different textures intersect, they create a discontinuity of the pattern =topological breakage  Reflected light off a surface also tells us how smooth it is o Scatter reflection= degree to which light scatters when reflected from a surface o Gibson’s transformation theory= as the observer moves, the entire optical array changes, which equals changes in optical info on the eye  Concept of movement led to the optic flow field= the movement of objects or of the observer through the environment produces changes/transformatns in what is seen  Ex. moving dots on a screen : you can tell the motion  Gibson was against the idea of illusions explaining perceptn, and focused on the everyday visual info that we pick up Pattern recognition  Theories of pattern recognition differed from Gibson in 2 ways: o Don’t consider the array of light info reflecting off surfaces (rather, the focus is on specific objects/ patterns) o Don’t focus on how info is directly perceived (rather on how we build internal representations of objects)  Pattern recognition= ability to recognize an event as an instance of a particular category of event o Recognizing something involves both the emerging percept (=meaningful interpretation of sensory info) + memory  ex. forming a memory trace(=a trace an experience leaves behind in the brain) after seeing the letter ‘a’.  Hoffding function= when an experience (an emerging percept) makes contact with a memory trace, resulting in recognition!  Template matching o Template=a model against which a stimulus is compared to determine whether it belongs to a particular category o Idea is that we store templates in our memory. The prototype= a model that has all the characteristics of its class o Template matching theory states that when we compare a stiumulus with a template, and when they match, the stimulus is recognized as being in that category (ex. A a a a )  Problem is to match template with similar patterns too o Hintzman’s multiple-trace memory model= traces of each indvl experience are recorded in memory. No matter how often a particular event is experienced, a memory trace of the event is recorded each time  Accounts for prototypic effects too.  It distinguishes between primary (the present) + secondary memory (all the memory traces)  2ndary memory can be activated by means of a probe from the primary memory  the probe from 1 memory to 2 activates memory traces that are similar to the probe st  this returns an echo to the 1 memory  choir metaphor: you can’t trace one voice, rather a general impression of the whole  Study: prototypical patterns (with dots)  Distortions are made to the prototype and those are what are shown to the P  Without ever having seen the original, the P can tell which one is the prototype  Hintzman explained these results by saying the distorted patterns produce a collection of echoes that lead to the recognition of a particular prototype (even if never seen before)  Feature detection theory o Selfridge: detecting patterns on the basis of their indvl features o A simple version of his pattern recognition model= pandemonium= a model consisting of 3 levels  Bottom level: the data/ image  Image has features (=component of the stimulus) ex. size/ colour/ shape  2 level: cognitive demons= a feature detector that decides whether the stimulus matches the pattern  are like little elves that detect each indvl feature  if a demon recognizes something, it shouts  the more similar an image, the louder it shouts/ + many demons shouting= even louder!  Top level: Decision demon =feature detector that determines which pattern is being recognized o Contrast energy= degree of contrast between letters in a word and the background ; leads to relative ease with which a stimulus can be discriminated from (ex. black words on white)  the more letters in a word, the more contrast E required  squelching= tendency of the NS to inhibit the processing of unclear features (ex. in low contrast E)  Recognition by Components (RbC) o model based on subdividing objects into basic set of geometric shapes  an object on the retina gets de-segmented into any combination of the 36 types of geons= basic geometric shapes that comprise objects  object geons are compared with geons in the memory, and when there’s a match= recognition!  Various studies manipulate the number and/or complexity of the geons  More detailed objects were easier to identify  More complex objects were easier to identify o Recoverability =degree to which geons can be made out in a degraded object; geons that can’t be extracted, are so unrecoverable= can’t recognize object. Context and knowledge  Bottom-up/ data-driven processing= when perception/ cognitive processes are driven by expectations and knowledge o but this doesn’t explain illusions  top-down/ user-driven processing= when perception results from the combination of indvl pieces of sensory info o based on experience, user constructs a clearer picture of objects o context effects= influence that the situation plays on the perception of a stimulus o ex. Moon illusion= tendency for the moon to appear larger when n the horizon than when high in the sky  apparent-distance theory= an explanation of the moon illusion, that the moon appears larger due to ‘distance’ cues  angle-of-regard theory= another explanation of the moon illusion, stating that the zenith moon appears smaller than the horizon because a person has to raise his or her eyes to view it  Letters in context o Jumbled word effect= ability to read wrdos in steentces dspeite havnig the ltteers mxied up in the mddile of the wrods.  Due to expectations o Word superiority effect= easier to identify a letter (ex. D) if it appears in a real word (ex. WORD) vs. a non-word or even alone o Connectionist approaches of letter perceptions make use of parallel distributed processing (PDP)=a model of perception that proposes that different features are processed at the same time by different units (simpler processing elements) connected together in a network.  Colours in context o Purves and Lotto study on colour illusion of a cube: shows that perception of colour is influenced by the perceptual context  P&L: empirical theory of colour vision= that colour perception involves not only processing wavelengths of light but also the influence of prior experiences about how different lighting conditions affect the appearance of colours in objects  Cross-modal context o We’ve only considered the visual modality, but it can cross others too o Auditory info affected by visual processes  Ex. ventriloquism: we perceive something different from what there actually is due to prior experiences  McGurk effect= auditory experience of the syllable ‘da’ when seeing a mouth silently saying ‘ga’, while at the same time hearing a voice say ‘ba’ The Grand Illusion  Change detection o Our experience of a picture-like world may be just an illusion o Study: show 2 pictures, where only one detail is altered, and flash both images with a blank screen flash in between each image  result: many didn’t detect the change  However if blank screen flash is taken away, change is seen almost immediately  Therefore in real life, motion detection allows us to become aware of important changes in the environment o Change blindness= common failure to notice changes in object/scene o Grand illusion of perception= experience of a clear and detailed picture of the world in one’s visual field  Using a lot of top-down interpretation of fragmented info  Feature integration theory o FIT= before we can attend to objects in the world, we must extract the features that make up these objects (we do so almost automatically)  We do this through the process of preattentive processing  For an object to be perceived as a whole, there needs to be feature binding= combining visual features to a whole by attn.  Accomplished through attentive processing  Therefore, out of everything we see, only one or few objects are bound as a whole, and the rest is blurry  Objects/ features are recognized when they pop out =grab attn  Constraints of the visual system o Can’t have a high fidelity percept of world because  Visual info is degraded as it moves through organs  Information from all areas of viewed space have different represented spaces in the brain (physiological level)  Foveal vision= more details/ periphery= blurred  Perceptual filling-in o Blind spot= area in the eye where the optic nerve leaves; does not contain any photoreceptors! (light here doesn’t even get processed)  we don’t experience this blank spot due to the brain filling-in  =(aka) perceptual completion= when something is present in a visual scene, is actually absent from that spot, but present in the surrounding region Perceiving whole objects: Gestalt psychology  = a branch of psychology that focuses on dealing with wholes vs. parts o principles that combine features toward experience o bi-stable figures (=images where two separate percepts can be formed) show that what we see is not always so straight-forward  ex. image of odl/young woman, or duck/rabbit  Kohler: ‘gestalt’ = any segregated whole  Central ideas o Perception is holistic =focusing on the whole configuration  Vs. atomistic = focusing on the features o There are fundamental organizational principles (=rules that explain ways people can perceive whole objects), by which we group (=combine) visual elements into a whole  Organizational principles (6) o Principle of experience= states that elements are grouped based on the prior experience and knowledge of the observer  Least endorsed  Based on process of figure-ground segmentation= perceptual organization of a scene where one element becomes the foreground (figure) and one the background (ground)  Ex. with bi-stable figures  (Peterson &Gibson) study: used denotivity= degree to which an object is meaningful and familial to a person  used this to capture differences between the regions: high/ low denotivity (meaning/ familiarity)  results show experience does influence fore-ground  Gestalters then focused on 5 principles of grouping: o Principle of proximity= things that are near on another are grouped together  ex. parallel lines next to each other vs. further apart o Principle of closure= things that form closed shapes are grouped together we group things that would close an image o Principle of good continuation= group elements that form smooth and continuous lines  ex. a rectangle vs. a sharp/ jagged object o Principle of similarity =things that are similar are grouped together  ex. when pairing up shoes in a clustered closet o Principle of common fate= things that are moving in the same direction are grouped together  idea of motion detection  Percept of object can stay after the elements stop moving too  Showed that principles of grouping are rooted in neural fnxns o These principles have been shown to fnxn ceteris paribus  Limitations of the Gestalt perception o Gestalt doesn’t take into account complex situations of grouping elements- ex a forest, where a woman’s face is carved in a bark tree  Gestaltist’s error= assumption that whole objects should always dominate over the elements of an image  Processing of local elements sometimes overrides the hole pattern and determines what we perceive Dissociations of perception  Agnosics +other disorders have revealed more complex aspects of perception o Various disorders show there are distinct and dissociable visual processes that serve different or overlapping fnxns  Apperceptive agnosia= type of visual agnosia; difficulty matching or categorizing objects ; can’t properly copy drawings or judge orientation  Optic ataxia= neural deficit where subject can identify objects but can’t accurately reach for them / interact with them manually  Prosopagnosia= impairment in ability to recognize faces(but can w/objects) o Can’ consciously recognize faces, but can unconsciously through Skin conductance response= small increase in the conductivity of skin surfaces when an indvl is aroused from a familiar face  Capgras syndrome =condition marked by the belief that significant others have been replaced by imposters/aliens; have no skin conductance response Ch.4- The Varieties of Attention James’s Description of Attention  His book in 1890s: “attention is taking possession by the mind”  Now we no longer think the word ‘attn’ means one process o (Pashler): “attn refers to a variety of possible processes and methods” o no clear definition Selective Attention  (Broadbendt) dichotic listening task= when Ps are exposed to 2 verbal messages presented at the same time, and are required to answer questions posed in only one of the messages o in this task, Ps were good at selective attention= attending to relevant info and ignoring irrelevant info  i.e. when they knew which msg had the relevant info, they attended more accurately to it  cocktail party phenomenon= capacity for attending to one convo in a crowded room in which many other convos are going on  (Cherry) used the shadowing task= exposing a subject to 2 messages simultaneously while repeating one of them o 2 messages: 1 in EACH EAR o when the P is repeating one of the 2 messages as it is heard, he is shadowing the other message (attending to 1msg, ignoring the other)  people filter info they don’t attend to  = a stage of info-processing that admits some messages but blocks others  selective looking= visual version of dichotic listening/ occurs when one is exposed to 2 events at the same time, but only attends to one o ex. like watching 2 tv shows at the same time on one channel  Both selective looking+ dichoting listening demonstrate results of o early selection in attention= hypothesis that attn. prevents early perceptual processing of distractors (that are irrelevant)  We literally don’t see/hear irrelevant info to us o Late selection= hypothesis that both relevant and irrelevant data are perceived, but then we actively ignore the irrelevant stimuli in order to focus on the relevant ones  Other studies (ex.stroop test) are more consistent with this  The Stroop Task o = a list of colour names, each of which is printed in a colour other than its name  ex. names ‘red, green, blue’ are written in blue, red, green  the tendency to read the name often interferes with the tendency to read the colour o A typical stroop experiment + variations compares performance in an incongruent condition (ex. word ‘red’ printed in green + read colour) with control conditions (ex. non-word printed in green + read colour)  Incongruent RT > congruent RT condition o This task shows that Ps deliberately inhibit reading the colour (our reflex) in order to be able to name the colour o Stroop tasks demonstrate automatic vs. controlled processes=  Controlled= processes to which we must pay attention in order to execute them properly  = top-down, goal-directed, voluntary  vs. automatic=processes that runs itself without the necessity of our paying attn to it  = bottom-up, stimulus-driven, involuntary o hypnosis and the Stanford Hypnotic Susceptibility scale is one way of investigating the Stroop task: seeing how people vary in extent of being hypnotized  Ps given process ex. being annoyed by (non-existent) mosquito  Those who are highly suggestible= susceptible to hypno  Then they were given the stroop test, and the highly suggestible ones did not show the typical effect (the less did)  Possible suggestion: reading of words is suppressed in the highly sugg. Ps, enabling them to easily name the colour the word is printed in  Basically shows that automatic processes too can be susceptible to top-down influences ! o These studies compared blood flow to different brain regions involved in the incongruent/ controlled conditions :  Dorsolateral prefrontal cortex (DLPFC)= (dorse= top) top- down bias; favors selection of task-relevant info  Important for exerting control  Anterior Cingular cortex (ACC)= detects conflicting response tendencies ex. those in the stroop task  ACC has a lot of speculation in its function  Might be active simply when someone is aware of conflict  more responsible for ‘attnal control’  These areas aren’t involved in all such competing tasks, but are recruited at times  Attention Capture and inattentional blindness o Attention capture= power of some stimuli on some occasions to elicit attention in spite of the fact that we did not intend to pay attention to them  ex. when someone says your name in the hallway(not to you)  Ecological sense- in the environment we have our attn. captured on objects that are important: threat/ opportunity?  We are tuned to pick up such cues o Inattentional blindness= failure to attend to events that we might be expected to notice  many accidents can happen  C.f selective looking: study: showed a video where there were 2 teams (white + black tshirts), where one passed a bball  Only 50% of Ps noticed the random black gorilla  Study with focus on relative lines and suddenly added a black square that Ps failed to see simple categories aren’t detected  Study: same as above, but cartoon face instead of black square, and this was detected 85% of the time  Showed that FACES were more special  Flanker task= experiment which Ps may be influenced by an irrelevant stimulus beside the target o Congruent condition: picture of a famous face (ex. Bill Clinton) and have to find the name (Bill Clinton) in the list of words o Incongruent condition: pic of famous face (ex. Bill) and have to find another name (Ex. MJ) o Ps were told to ignore the face o Results: incongruent RT > congruent RT = faces weren’t ignored, interfered with RT!  When this flanker experiment was done with musical pictures + instruments (instead of names and faces), the opposite results occurred  Mandatory face attention, even when our goal is to ignore them  Same goes with other representations of the body o Domain-specific models= hypothesis that parts of the brain are specialized for particular tasks, ex. face recognition  Maybe it’s only the case with certain body parts  Person’s own name has the power to capture attn.  =highly meaningful stimuli are able to catch our attn.  ex. mom waking to her child’s cry o meaning is the first determinant of selective attention, and thus also of perceptual consciousness  Perceptual cycle= our expectancies guiding our exploration of the environment, but also our environment being capable of influencing our expectations. Dual Tasks and the Limits of Attention  How many things can we attend to at once?  Capacity model= hypothesis/ metaphor that attention is like a power supply that can only support a limited amount of attentional activity o the more tasks, the more fuel in the tank gets used up  Structural limits= hypothesis that attentional tasks interfere with one another to the extent that the share similar activities o If 2 tasks require the same activity, more likely to interfere  Ex. 2 verbal tasks at once = impossible  Central bottleneck= hypothesis that there is only one path through which information relevant to one task can pass at a time o Adding another task would make you have to switch your central processor to another tasks doing 2 things at once require you to be constantly switching and selectively only attend to one at a time o If you do succeed at attending more than one thing at a time = divided attention  with practice, attention could go beyond limits  Study on divided attn.: trained 2 people for 6 weeks to get them to read words and copy dictated words simultaneously  Were able to understand the topics of what they wrote down, while also understanding what they read  People usually make inferences about what they hear, and falsely write that down instead of the actual sentence  Keep in mind, these hypotheses don’t disprove the idea that we are just rapidly switching mental operations vs. 100% 2 tasks o Other studies with the central bottleneck idea show that no evidence was found where one could not be overcome by the bottleneck with the right amount of practice (where dual task performances were similar to if the tasks were done alone) Task Switching  Set= temporary, top-down organizations that facilitate some responses, while inhibiting others, in order to achieve the person’s goals o There are many types of sets: preparatory sets (ex. sprinters on the starting line), executive sets (guide organisms thru sequences, ex. driving), and goal sets (represents aims) o They act as temporary organizations in the brain to facilitate response  And thus preventing/ inhibiting other responses  Task switching= people must change from working on one task to working on another. Usually studied in situations in which the switch is involuntary o Ex. if typing an essay, suddenly get an e-mail to paying fees at an office, so you walk to the office and some friends stop by  3 tasks: essay, pay bill, talk to friends  each require an appropriate amount of mental resources, a ‘task-set’/ ‘schema’ o switch cost= finding that performance on a task immediately declines after a switch (vs. not switching at all)  time is required to reconfigure your cognitive system back  keep in mind boredom makes switching costs easier  studies allowing longer preparation time do not result in better performance – people are NOT aware when they’re ready  ppl can be aware of the goal, but not of the executions Attention, Awareness, and unconscious processes  people are not aware of all the things in their environment of which they cold be aware of  different people have different account of the same things o encoding= process of transforming info into one or more forms of representation; largely automatic, fast and unconscious  we code events without knowing, otherwise there’s tmi!  Ex. professional sports: don’t pay attn. to smallest routines  An event can be encoded multi-dimensionally  Perception without awareness o = a stimulus that has an effect even though it is below the Ps subjective threshold of awareness o Subliminal perception= when a stimulus has an effect on behaviour even though it has been exposed too rapidly or at too low an intensity for the persona to be able to identify the stimulus  Limen= threshold// Ps threshold for reporting the occurrence of an event // a stimulus ‘below threshold’= ‘subliminal’  Often involves semantics= study of meaning  Problems: how can we e sure that a stimulus presented below threshold was not actually seen?  Backward masking o =presenting a stimulus (the target) to the P and then masking it/ covering it with another stimulus o stimulus onset asynchrony (SOA)= time difference between the first and the masking stimulus o ex. showing a word, then masking it with a pattern o priming= tendency for some initial stimuli to make subsequent responses more likely to occur  the stimulus word shown before the pattern acts as a prime o indirect measures= measuring the effect of an undetected stimulus on a subsequent task  these show better perceptual processes o direct measur
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