Psych 120A Midterm I

Attention

"Everyone knows what attention is. It is the taking possession by the mind, in clear and vivid form, of one out of what seem several simultaneously possible objects or trains of thought. Focalization, concentration, of consciousness are of its essence. It implies withdrawal from some things in order to deal effectively with others, and is a condition which has a real opposite in the confused, dazed, scatterbrained state." (William James, 1890)

Propositional Representations

"My claim, that the theoretical construct required to explain the phenomena surrounding mental imagery had almost none of the characteristics associated with pictures, met with enormous and widespread resistance. I soon realized that what was at stake was a serious misunderstanding of what one had access to through conscious introspection. When you introspect and you see an image of a large heavy green tree-shaped thing there is nothing in your head that has any of the properties 'large,' 'heavy,' 'green,' or 'tree-shaped'—those are properties of the thing you are thinking about." - Zenon Pylyshyn

fMRI: Cons

- Although temporal resolution (1-4 sec) is much better than PET scans, still much slower than measuring actual neural activity - Very expensive - Scanner noise is very loud

PET: Pros

- Decent spatial resolution (5-10mm3) - Can also measure neurotransmitter metabolism. - Can aid in diagnosis of disorders such as Alzheimer's disease Carbon 11 binds only to amaloids in brain, amyloid plaques seen in Alzheimer's disease - Very quiet (good for auditory experiments)

PET: Cons

- Invasive (radioactive injection) - Very expensive - Poor temporal resolution - Cannot detect the neural response to discrete cognitive events.

PET: Cons

- Invasive (radioactive injection) - Very expensive - Poor temporal resolution bad ability to pinpoint time - Cannot detect the neural response to discrete cognitive events.

Top-down effects of context

- a stimulus looks perceptually identical 13 and B, some info coming in interpretation is different, dependent on context - blobs of ink d and b are identical, r and p

Effects of cell phone use on driving performance

- driving while talking w/ passenger -driving while conversing via cell phone -is it the act of holding it in your hand? -even hands free is distracting -passenger vs. cell phone more distracted when the person isn't there, might mentally be taking more effort, passenger might alert you to problems but cell phone can't

illusory motion

- due to effects of tiny eye movements (microsaccades) -periphery shows the effect as you make microsaccades

- fictions

- fictions: perception of things that are not there

Adjusting the "beam of attention"

- globally see the skull, zoom in narrowly and see the woman in the mirror

Focusing attention involves a trade-off

- looking at display broadly -can tell certain characteristic (horizontal/vertical lines, black and red colors) -get the idea that there are both colors and lines, acnnot ask if all vertical ones are red or ask a specific question, people feel like they percieve it accurately but they guess Focusing your attention involves a trade-off: If you focus your attention broadly, you can take in many inputs at once, and this is faster (because you don't have to search through the items one by one). But, since you're taking in multile inputs simultaneously you may ot know which feature belongs with which. In contrast, if you focus your attention narrowly, you'll be slower in your search (because now you do have to search item by item), but, with information coming from just one input, you'll know how the features are combined.

paradoxes

- the penrose triangle -all features make sense locally, but figure doesn't work when processed globally -disconnect between local and global

Patient PV: single consonant memory task

-100% correct when visual C on screen -auditory: says C and repeat it back but if you wait 3 seconds its up to chance (not 0 because it gave her a choice)

Search times can be influenced by set size

-As number of stimuli in display increase, conjunctive search (serial) time increases -As number of stimuli in display increase, disjunctive search (parallel) time stays the same But... the story is actually a bit more nuanced ̈ As the similarity between target and distracter increases, so does the difficulty in detecting the target stimuli ̈ Factors influencing search: ¤ Similarity between the target and the distracters ¤ Similarity among distracters ̈ It's NOT about the number of features per se, but just about the confusability of items

Memory in Amnesia: Working Memory vs. Long-Term Memory

-HM had iparied long term memory but intact working memory, tesitng memory shortly after -normal controls showed recency and primacy effect -amnesic patients show the same pattern, normal recency effect because that doesn't depend on hippocampus at all, remembers almost none in the middle, some primacy effect but it is imparied by hippocampal damage effects middle too

Decoding Individual Mental Images From fMRI Activity

-PPA (Parahippocampal place area) responds to landscape scenes and landmarks etc -FFA (fuisiform face area) -85% of the time could predict what stimulus they were to imagine from the fMRI graph But the propositional theorists were still not convinced ̈ "...so desperate are those who seek a neurophysiological explanation of the bankrupt picture theory of mental imagery that they take almost any neuroscience finding as support" - Zenon Pylyshyn (2002)

Cerebral Hemispheres

-allow left and right side of brain to communicate with each other - 2 hemisphere seem to have biases in how they process information Stimulus is a big M made out of z's or a triangle made out of rectangles -damage to right hemisphere: sees the z's, damage to left hemsiphere: sees M but misses the Z (global) if left hemisphere is damaged miss analytic aspect to fine details, right hemsiphere damage focus more on fine grain detail and miss the holistic -no neural correlates of being "left-brained" or "right-brained"

Neural Processing of illusory contours

-an edge that's not there -illusory lines "detected" by V1 neurons because line is not presented in stimulus, must be due to top-down feedback signals from higher cortical areas -neural response to illusory line is weaker and delayed relative to regular visible lines -actually looking at line: neuron has high response -looking at grey square against white background: neuron has slighly lower response -white square against grey background: biggish response ^^^ real edges the neuron is detecting -illusory contour-V1 is saying that there's nothing there, but if fires around 120 ms b/c top-down feedback signals that they think there is a square or edges -feedback signal, that's why the peak is delayed

Double dissociation within WM

-can get damage that impairs one and spares the other - Suggests that working memory is not a unitary function

Cueing Sleep-Dependent Consolidation

-concentration style matching game -learn where objects are, during learning they were presented with an odor or not (vehicle-puff w/o smell), have them sleep in scanner where they monitor sleep stages, does giving odor during retrieval help context and learning?, sleep w/ odor, unconscious, during retrieval do much better with odor -odor triggers memory retrieval in hippocampus -same odor during learning and sleep then boosts memory a lot -odor only during sleep didn't boost learning -the possibility of targeted memory reactivation during sleep -certain sounds or smells during sleep: targeted memory reactivation spontaneous reactivation: less control over what you want to actually commit to memory during sleep (salience, intention, novelty, reward, instruction)

Hemispatial Neglect- Objected-centered neglect

-diagonal object, attention zoomed in on object, with respect to the object, the left side is ignored, not the left side of the visual field Patients can neglect the left side of the object, rather than the left side of space. Black lines show expected left-sided person-centred versus red lines showing actual point where the patient neglected

The human hippocampus

-hippocampus: in medial part of temporal lobe, sea-horse shaped structure,

Inattentional blindness

-inattentional blindness -task is asked to pull their attention here, at center point, they can be asked to move attention independently of your eyes in the corner, -in some trials the circle changes shapes, asks does the circle change shape, if no warning that something changed, they would not detect it, if you were warned more likely to detect change Participants were instructed to point their eyes at the dot and to make judgments about the cross shown just off to the side. However, the dot itself briefly changed to another shape. If participant were not warned about this (and so were not paying attention to the dot), they routinely failed to detect this change--even though they had been pointing their eyes right at the dot the whole time. If participants were warned, though, and therefore alert to possible changes, then virtually all participants detected the change. -radiological scan -weren't expecting gorilla so didn't detect it, weren't processing it ̈ Only 4 out 24 radiologists saw the gorilla ̈ Eye-tracking data showed that radiologists spent 5.8 seconds looking at the scan with the gorilla ¤ Out of the 20 radiologists who did not see the gorilla, 12 had looked directly at it

The "Modal Model" of Memory

-info from world comes into mind through sensory registers (haptic = touch), things you pay attention to will enter STM -some may make it into LTM, most is just used to navigate through the world Atkinson & Shiffrin (1968) Input -> (Sensory registers (visual, auditory, haptic)) --attention--> (Short-term Mem. (STM) temporary working memory, Control Processes: -rehearsal, -recoding, -retrieval strategies) <---> long-term mem. (LTM) Permanent memory store ̈ Sensory memory trace: ¤ The initial sensory trace contains more information than we can ultimately remember! ¤ Iconic memory traces decay by 300 to 500 msec ¤ Echoic memory traces might last ~2-4 sec ̈ Short-term memory (STM): ¤ Longer lasting than sensory stores (~18 sec without rehearsal) ¤ Available to 'conscious access' ¤ Processes to regulate flow of info to & from LTM

Event Retrieval: Reconstructing Past Neural Patterns

-later on, if one goes back to las vegas, see the sign, triggers some bisual memory, when you activate node part of original experience, activates other nodes part of the experience, re-activated, nodes send signal back out to cerebral cortex, revisiting past experience and thinking back the details perceptual qualities are all reconstructed, reactivating past, PATTERN-COMPLETION

Contextual effects on memory: A changed environment can hurt recall

-learn words on land or underwater -data tested in similar environment than context of study does best internal cues part of context, even though not testing context, reexperincing context can activate the memory -statistically significant but not huge effects -study with noise do better with noise

Modularity vs. Networks

-localize regions with fMRI -look at how areas of the brain communicate with each other Functional Segregation - Localization of category-specific visual processing regions (LO, PPA, FFA) Functional Integration -Statistical modeling of functional interactions between brain regions

Memory Formation (Event Encoding)

-memory: sensory organs recieving info, details encoding the experience, dorsal and ventral stream processing, bottom up and top down signals, what happens in hippocampus? all areas in the brain part of the experience, context is, time, temporal info, professor dressed up as waldo feeding into hippocampus, info arrives simultaneously and hippocampus binds it together, indexing different parts of the experience

Attention is...

-selective: selectively focused -divisible: need to attend to multpile things -shiftable: you can move your attention to other spatial locations -sustainable: attend to one thing or place

State-dependent recall

-study drunk, do better drunk at recall ̈ Eich et al. also did a version of this experiment where subjects either smoked normal or marijuana cigarettes during study and/or test. State-dependent recall: Effects of Mood ̈Easier to remember happy memories in a happy state and sad memories in a sad state. ->mood primes certain memory contents

Hippocampus & memory consolidation: Transferring memories to neocortex

-what happens to memory over time? -less and less important over time?, it's importance diminishes, hippocampus isn't needed at all, specultive, over sleep, hippocampus synchronizes ewith cortical regions and form connections between the regions and hippocampus becomes unecessary, it can be used to encode new experiences but not needed to retrieve memory

What's so special about the hippocampus?

-wiring diagram of brain of cat monkey -circuit model -bottom: early visual areas -top: hippocampus at top b/c it's wired in such a way that even though doesn't directly connect many regions it receives info from all different parts of the brain, highly processed info

Henry Molaison (H.M.) & the Amnesic Syndrome

1942 first major seizure (age 16) 1953 bilateral medial-temporal lobe resection (hippocampus & nearby structures) 1955 first report of pervasive & profound amnesia 1962 neuropsychological examinations characterizing the amnesic syndrome -epilepsy, so debilitating so pursued surgery, took area where seizure started from, hippocampus more or less missing, could talk and walk after surgery but couldn't remember experiences, living in their moment, short-term memory is accessible but once that info fades from working memory doesn't seem to be stored -hippocampus wasn't completely removed,

Patients with damage to the cerebellum are impaired at mirror-tracing (but perform normally on declarative memory tasks)

=cerebellum: important for motor coordination -double dissociation!!! -if damage to hippocampus affects one thing (declaritive memory) but spares another (procedural memory) it's a single dissociation, but is declaritive memory harder than proceduarl memory, compelling evidnece against that -damage to cerebellum effects procedural memory but not declaritive

Magnetic Resonance Imaging (MRI)

A 3.0 Tesla MRI Scanner (like many of the scanners we have here at UCLA) 1 Tesla (T) = 10,000 Gauss Earths magnetic field = 0.5 Gauss 3 Tesla = 3 x 10,000 ÷ 0.5 = 60,000 X Earth's magnetic field

Magnetic Resonance Imaging (MRI)

A 3.0 Tesla MRI Scanner (like many of the scanners we have here at UCLA) 1 Tesla (T) = 10,000 Gauss Earths magnetic field = 0.5 Gauss 3 Tesla = 3 x 10,000 ÷ 0.5 = 60,000 X Earth's magnetic field Magnets attract metal objects Send pulse of radio wave that tips the H2O molecules out of alignment

What are visual images?

A kind of mental representation, sharing certain properties with pictures: 1) Preserves metric spatial information 2) Changes with viewpoint 3) Empty space explicitly represented 4) Experienced using spatial attention q Mental imagery may involve any of the sensory modalities qImagine a sight, sound, taste, touch, or smell - not only visual images, can have auditory images too - golfer using motor and visual imagery - imagery is important in meditation PTSD: vivid, negative imagery come back easily Depression: imagery of positive experiences are weak

Inattentional blindness and unconscious perception

A) subjects looked at these display, lights flickered around, which line is bigger? some trials had top/bottom bigger or the same, dark dots arranged randomly, didn't notice on some trials dots lined up and made B) illusion, particpants weren't consciously aware of the orientation but reported the top line bigger, unconsciously illusion incresaes the estimate of the top line

Potential difficulties with RBC model

A. Structural description not enough, also need metric info, length of geons matter too B. Difficult to extract geons from real images C. Ambiguity in the structural description: most often we have several candidates D. For some objects, deriving a structural representation can be difficult, shoe is hard to make with geons ̈ RBC model also does not include a mechanism for contextual influences on object recognition THE CAT where the symbol for H and A are the same but percieved differently same stimulus but contxt of letters surrounding it influences perception

Anterograde amnesia

Anterograde Amnesia - the inability to remember events you experience (episodic memory) and facts you encounter (semantic memory) after the brain injury -everything after is anterograde amnesia, can't learn new declarative memory after amnesia

Hemispatial Neglect and mental imagery

Bisiach & Luzzatti asked Italian neglect patients to imagine themselves in the a particular location at Piazza de Duomo and to report what they could "see" - neglecting retrieving memory of imaging things in space, even mental images you pull out of memroy shows bias of attention to 1/2 of visual field

Event-Related Potentials (ERPs)

Characterizing electrical activity changes evoked during specific cognitive events ERP example: The face-selective N170 component

The logic of "cognitive subtraction"

Cognitive subtraction is founded on the assumption that it is possible to find two tasks (an experimental and baseline task) that differ in terms of a small number of cognitive components. The results show several regions of activity but only the main results on the left lateral surface are depicted here.

Conjunctive search

Combined Feature (Conjunctive search) ̈Acombinationof features need to find the target. ̈ Done by checking each item (serial) ̈ Demands attention -combined feature search: scan throw and check each one -ex. Look for something red AND O

Contralateral Organization of Vision

Contralateral vision and motor, info from left visual feed is sent to right and vice versa Each eye sees both sides of the world but once you get to the optic chiasm it gets lateralized

Implicit processing of unattended hemifield: Patient P.S.

D. "What do you see?" PS: "A house" D. "And now?" PS: "A house" D. "Are they the same or different?" PS: "The same" D. "Anything wrong with either?" PS: "No" D. "Which one would you live in?" PS: "They are the same" D. "Choose one" PS: "The top one" [9/11 times] - D = doctor - PS = patient - even though patient is unaware that a fire was draw, the info coming into visual system is influencing them unconsciously

Decoding much finer-grained mental images from fMRI activity

Decoding imagery of X's vs. O's Imagery Decoding Results: Activity patterns in left lateral occipital region could predict what the subject was imagining 62% of the time (significantly better than chance) when actually looking at X's and O's there are certain areas that activate, they learned the pattern of the brain Decoding more complex mental images: Imagining specific paintings Reconstructing visual experiences from fMRI brain activity patterns measured during movie viewing

Summary: The hippocampus and memory

ENCODING: • The hippocampus plays a critical role in the formation of new declarative memories (both episodic and semantic) • Facilitates binding of many different types of event details into a coherent episodic memory • Damage results in anterograde amnesia • But, non-declarative (implicit) knowledge can still be acquired RETRIEVAL: • By indexing the inter-relationship between event elements, the hippocampus can contribute the recollection of episodic memories (not typically involved in semantic memory retrieval) • As time passes, episodic memories become gradually consolidated in cortex and depend less on hippocampal indexing • Damage results in temporally graded retrograde amnesia -basal ganglia and cerebellum can leran implicit knowledge independent of hippocampus -damaging hippocampus doesn't usually effect semantic memory -damage to hippocampus usually effects both retrograde and anterograde amnesia

The Kanisza Triangle

Famous fiction example

The lobes of the brain

Frontal lobe Central fissure Parietal lobe occipital lobe cerebellum temporal lobe lateral fissure

Tissue types

Gray and white matter white matter: bundles of axons covered in myelin sheath (insulating wires of electric signals, keeps it from losing strength) gray matter: cell bodies heavily packed in, cerebral cortex? • The gray matter of the brain contains the cell bodies of the neurons • The white matter contains the axons - Axons are covered with myelin, which insulates and increases the speed of conduction

Hemodynamic Response Function (HRF)

Hemodynamic Response Function (HRF)

Hippocampus & memory consolidation: The importance of sleep

Hippocampus "teaches" the cortex during sleep -hippocampus linked to memories -in sleep, hippocampus training cortical regions -waking up (maybe takes more than 1 night) frees up hippocampus to do other things, not indexing things, just keeping track of recent experiences

Contextual effects on word recognition

I cnduo't bvleiee taht I culod aulaclty uesdtannrd waht I was rdnaieg. Unisg the icndeblire pweor of the hmuan mnid, aocdcrnig to rseecrah at Cmabrigde Uinervtisy, it dseno't mttaer in waht oderr the lterets in a wrod are, the olny irpoamtnt tihng is taht the frsit and lsat ltteer be in the rhgit pclae. The rset can be a taotl mses and you can sitll raed it whoutit a pboerlm. Tihs is bucseae the huamn mnid deos not raed ervey ltteer by istlef, but the wrod as a wlohe. Aaznmig, huh? ̈ Not entirely accurate, but nicely illustrates the powerful role of contextual support

Disjunctive search

Isolated Feature (Disjunctive search) ̈Singlefeatureenough to find target (not shared with distractors) ̈ Done in parallel ̈ Not attention demanding ("preattentive") - disjunctive search: doesn't need a lot of attention -done in parallel (doesn't have to search stimulus by stimulus, can look at the entire picture at once) -1 feature map

Two types of search

Isolated Feature (Disjunctive search) ̈Singlefeatureenough to find target (not shared with distractors) ̈ Done in parallel ̈ Not attention demanding ("preattentive") Combined Feature (Conjunctive search) ̈Acombinationof features need to find the target. ̈ Done by checking each item (serial) ̈ Demands attention - disjunctive search: doesn't need a lot of attention -done in parallel (doesn't have to search stimulus by stimulus, can look at the entire picture at once) -combined feature search: scan throw and check each one

Modern Brain Imaging: MRI and fMRI

MRI studies brain anatomy. Structural MRI scans are useful for clinical imaging (diagnosis) Functional MRI (fMRI) studies brain function. -get fMRI image every 2 seconds more blood flow disrupts magnetic field giving us a correlate of neural activity fMRI Blood Oxygenation Level Dependent (BOLD) signal indirect measure of neural activity higher neural activity -> higher blood oxygen -> higher fMRI signal -As the ratio of oxygenated to deoxygenated hemoglobin increased, BOLD fMRI signal increases -Contrasting BOLD activation across conditions (cognitive subtraction) BOLD signal change during presentation of static and moving visual stimuli -primary visual cortex Doesn't care if moving or static -Area MT Area sensitive to moving stimuli

Retrograde amnesia

MTL damage impairs not only new learning, but also disrupts memories acquired before the injury (Retrograde Amnesia) -retrograde amnesia is a gradient not a solid color, taking out hippocampus, couldn't remember things closest to injury date, later memories are consilidated which takes time and not dependent on hippocampus, gradient has a range for levels of damage -Ribot's Law (1881): the vulnerability of a given memory is inversely related to the time of its intitial formation. (recently formed memory is more vulnerable than older memories) -normal memory vs. anterograde amnesia A) Normal memory - things that happened today will be easier to recall than something happened year ago, straight-ish line increasing with slope of 1 B)anterograde amnesia - things you happen forward won't rembmer, before injury would show a normal curve C) anterograde and retrograde amnesia retrograde amnesia is graded (time-dependent) gradual over time), graded decline closer to time of damage

Other ways to improve memory: Spaced vs. Massed Encoding

Massed encoding: table table table apple apple apple fair fair fair Spaced encoding: table... apple... fair... table... apple... fair... etc. Which is better? Massed encoding: massing it together spaced encoding: is better? spacing out interweaving (study history then chem then etc) is better, waitining a little bit, spacing apart will be advantageous

Single-unit recording (usually in animal studies)

Measure activity of a single neuron with electrode probe -- map out the cell's receptive field V1: 1st level of cortical processing, move stimulus around in space and see the neuron's receptive field, not every neuron in visual cortex will receive info about everything in space - every time you see a line is an action potential, when certain things happen fires more rapidly - neurons will fire at baseline rate so always will get some spikes, don't get no spikes - some cells sensitive to orientation-specific -ex. cell responds more to vertical bars - some cells are sensitive to center-surround cells -B. cells firing rate goes up when stimulus presented in the middle of cell's receptive field C. below baseline rate when stimulus presented at edge of the cell's receptive field useful contrast of outside world, surrounding region may inhibit neuron D. stimulus presented in both center of receptive field and edge, cell's firing rate does not change from baseline

Patient H.M. could learn new skills (procedural memory)

Mirror Tracing Task wat about non-declarative memory? -skill training task, mirror tracing task trace start without going out the border, data shows how many times you go out of bounds, mirror reflects opposite, so you must do opposite of what you see so it takes skill learning, doesn't depend on hippocampus, first day after 10 trials gets a lot better, comes back day 2, doesn't remember doing the experiment but does better, by 3rd day almost no errors

The first cognitive PET study

Passively viewing words: activation in visual region Listening to words: temporal lobe? Speaking words: motor region Generating verbs: temporal and frontal lobe

The "short" of short-term memory

Peterson and Peterson (1959) A central idea regarding short-term memory is that information is only available for a very brief period if not rehearsed. The confusion of recent "long-term memory" with "short-term memory" -psychologists reserve the term short-term memory to refer to information that you hold actively in mind on a moment-to-moment basis -generally lasts less than 20 seconds -misuse of the phrase "short-term memory" -the only thing that Dory can do well is shot-term memory she doesn't have short-term memory loss, she can't form long-term memories, she has hippocampal amnesia -with verbal info, you can keep rehearsing it, maybe goes into long term memory -not rehearsing, info lost in short-term memory -background counting = distracting -in study rehearse letters, doesn't matter at 8 of 18 seconds, -counting ties up working memory system, prevents rehearsal, without rehearsal can only remember about 20% at 18 seconds

Primary sensory cortices and association cortices

Primary site: where senses initially arrives Associative site: nearby area Primary -> Association EXCEPT for motor cortex because dictated by brain telling muscle groups what to do Central Sulcus/Fissure divides motor and somatosensory cortex

Representations and Processes

Representation: A set of objects that stand for another set of objects by virtue of having the same causal relational structure. Processes: operations that transform one representation into another. Representations: set of objects that stand for another set of objects by virtue of having the same causal relational structure (represented world: external objects, representing world: internal representation) o Version of something in different format (e.g., maps as representation) o Mental representations: o 1. Are formed in the mind o 2. Make it possible to think about objects/events in their absence o 3. Reliably activated by objects/events in world Processes: Operations that transform one representation into another (1:1 or many to 1, clock -> visual, time that is left) o Mental processes: operations performed on mental representations o Creation, storage, retrieval, use for action, transformation, evaluation

H.M.'s Reflections on Memory

Right now, I'm wondering. Have I done or said anything amiss? You see, at this moment everything looks clear to me, but what happened just before? That's what worries me. It's like waking from a dream; I just don't remember. - H.M., 1970 -could remember things before surgery but not after

Key distinctions between STM and LTM

STM Active contents of consciousness Active nodes in LTM Fast access to contents Limited capacity Fast forgetting Transiently increased neural firing relative to baseline LTM Not currently in consciousness Inactive until cued Slower access Unlimited capacity Slower forgetting Plastic changes in synaptic connection strength -if you remember a past memory then it's in working memory -STM is active nodes in LTM -giving set of numbers to rehearse, each number has a representation in LTM like a node in long term knowledge -active thinking: increase in firing -LTM: changes in wiring

Support for RBC

Support for RBC: We can recognize partially occluded objects easily if the occlusions do not obscure the set of geons that constitute the object.

Taxonomy of long-term memory

Taxonomy of long-term memory

Solving the binding problem through temporal synchrony of neural ensembles

Temporal binding model - single face with candle stick in front or 2 people facing each other -4 hypotehtical neurons in receptive field -if single face, 1 and 2 (eyebrows are part of the same object) and 3 and 4 (candlestick are part of the same object -neurons are firing at the same time to bind these together, attention i binding this together -not the same thing as spatial spotlight attention -percieving it as 2 faces, now 1 and 2 are firing asynchrosingly 1 and 3 are in synchrony because they look like points of the same face and 2 and 4 fire in synchrony (dance t the same beat) synchronized firing patterns -best guess of how attention binds things together -synchrony binds features together from feature maps to make a single object

The Face Inversion Effect [a.k.a. "The Thatcher Effect" (1980)]

The face inversion effect illustrates that ...Our visual processing mechanisms for integrating facial features only work properly for upright faces.

What is cognitive psychology?

The scientific study of knowledge and thought: -Problem solving, decision making, reasoning, language, memory, attention, perception ̈ How is our knowledge of the world represented? ̈ What mental processes are involved in acquiring, accessing, and using this knowledge? ̈ How can we measure behavior to make inferences about mental representations and processes? ¤ Need carefully designed experiments! • The scientific study of knowledge and thought: o Memory, problem solving, decision making, reasoning, language, perception, attention • How is our knowledge of the world represented? • What mental processes are involved in getting, accessing, and using this knowledge? • How can we measure behavior to make inferences about mental representations and processes? o Use carefully designed experiments

Ventral stream lesion in patient D.F.

Top: Lesion reconstruction in DF in 2003 (hypoxia in 1988) Bottom: Region activated in fMRI in normal individuals during object recognition task (Objects - Scrambled Shapes) Apperceptive Agnosia: copy line-drawing -> drawn from models (dorsal stream guided) vs. drawn from memory (memory guided) line-drawing model of a spoon, when asked to draw from model, looks like a line with a upside down u in the center, when drawn from memory, better spoon

the primary projection areas

Topographic/ map-like association in these cortex -hands have a lot of cortex associated to them -assymetric some are over represented and under represented -the primary motor projection area is located at the rearmost edge of the frontl lobe, and each region within this projection area controls the motion of a specific body part, as illustrated on the top left. The primary somatosensory projection area, receiving information from the skin, is at the forward edge of the parietal lobe; each region within this area receives inputfom a specific body part. The primary projection areas for vision and hearing are located in the occipital and temporal obes, respectively. Tese two areas are also organized systemitcally. For example, in the visual projection area, adjacent areas of the brain receive visual inputs that come from adjacent areas in visual space

The Great Imagery Debate

Two differing viewpoints as to the nature of mental images The Analog Viewpoint: Visual mental images are analogous to pictures in the head ("functional equivalence") *** Championed by Stephen Kosslyn *** -image is a picture The Propositional Viewpoint: Although we may believe we experience images as "pictures," the underlying mental representations are actually non-pictorial abstract concepts. **** Championed by Zenon Pylyshyn *** -image is a description - propositional: state and fact of objects and how they're related to each other - Analog viewpoint: pictures in the head, should share same properties as viewing image - The propositional viewpoint: subjective mechanism of pictures is not really true, but abstract concepts

The history of functional brain mapping

Ventricular theory of brain function * Anterior ventricle controls perception * Middle ventricle controls cognition * Posterior ventricle controls memory Started with Galen came up with ventricular theory of brain fucntion -don't need to memorize this ventrical: fluid filled space, no info processing in ventrical

Hierarchical organization of visual perception

Visual Input -> Low level vision (Oriented bars/edges, Motion, Texture, Depth) <-> High Level Vision (Object/Face/Scene/Word recognition) <-> Knowledge low level vision -> mid level -> high lievel low level: basic features of visual world high level: what are we actually seeing, V1 -> V2 -> V4 -> IT pattern of converenge V1 has small receptive fields, V2 is recieving info from lots of V1 cells, so V2 gets info from a larger visual world, gets more abstract features like angles, V2 processes shape features like angles, V4 also has convergence, measuring from V4 cells some V4 cells might like certain shapes like triangles, IT cells have the largest receptive fields, don't care where the 'tea kettle' is, high level integrated features - one step further in the hippocampus, sensitive to certain objects, may have cells that respond when shown people such as jennifer aniston

Diffusion Tensor Imaging (DTI)

White matter: a more colorful view color coded shows direction of transmission

History of memory

William James (1890): postulated two forms of memory ¤ Primary memory n The immediate contents of consciousness n Effortlessly available and fleeting n Limited capacity ¤ Secondary memory n Memories of the past n Permanent but available with effort n Unlimited capacity Donald Hebb (1949): proposed distinction between short-term memory (STM) and long-term memory (LTM) mechanisms ¤ STM: relies upon temporary activation ¤ LTM: relies upon structural changes in neurons / connections -primary memory -can't keep track of too much stimuli -short term memory -secondary memory -long term memory -Hebb (looked at mechanistic, neuro perspective) -STM: firing constantly, keep neurons consistantly firing to keep things in mind -LTM: plasticity of neural connection, Taxonomy of memory -short-term memory (a.k.a working memory) -maintains and manipulates information relevant to one's current goals -Note: sometimes the term STM is reserved for simple information maintenance, whereas WM is used to imply maintanence plus manipulation -

White/gold Blue/black dress

assume it's in the shadow -> white/gold assume it's in bright light -> blue/black

Making sense of an ambiguous visual world

bottom up processes (data-driven) top-down processes (conceptually driven)

Top-down modulation of visual processing

bottom-up processing: object recognition top-down modulation: send signals to influence processing

The role of similarity

different distractors, harder have to find the template when distrators are more similar, easier

Converging Methodolgies:

fMRI guided-TMS with ERP recordings

Split Brain Patients

fixate on dot so each eye sees only one visual field, What word do you see? Ring Right visual field processed by left hemisphere controlling speech left hemisphere doesn't Reach for what you see AND use their left hand: Key, reads the word key but can't speak it

Split Brain Patients

fixate on dot so each eye sees only one visual field, What word do you see? Ring Right visual field processed by left hemisphere controlling speech left hemisphere doesn't Reach for what you see AND use their left hand: Key, reads the word key but can't speak it -In this experiment, the patient is shown two pictures, one of a spoon and one of a fork. If asked what he sees, his verbal response is controlled by the left hemisphere, which has seen only the fork (because it's on the right visual field). If asked to pick up the object shown in the picture, however, the patient--reaching with his left hand--picks up the spoon. That happens because the left hand is controlled by the right hemisphere, and this hemisphere receives visual information from the left-hand side of the visual world Visual stimulus with horse on left visual field (LFV) Examiner: what was it? what goes on it? Verbal response: i don't know Left-hand drawing: (saddle)

What is an Illusion?

il·lu·sion (î-l¡1zhen) noun 1. a. An erroneous perception of reality. b. An erroneous concept or belief. 2. The condition of being deceived by a false perception or belief. [The American Heritage® Dictionary of the English Language, Fourth Edition copyright ©2000] ̈ Latin root of illusion is illudere which means "to mock" ¤ Optical illusions mock our trust in our senses ¤ Suggest that the eye is not a passive camera ̈ Perception is an active process that takes place in the brain and is not directly predictable from simple knowledge of physical relationships As with many aspects of science, our knowledge of optical illusions can be traced back to the Ancient Greeks The Greeks appreciated the importance of visual angle

Early neuroimaging evidence (fMRI) for involvement of visual processing areas during visual imagery

imaging stimulus activates the visual cortex not as strongly but top-down influence

Viewpoint invariance

less neural activity to recognize object second time you see it -in fusiform gyrus regardless of same or different view in right occipital area =activates just as much as new object if it is in different, rotated orientation, sensitive to lower level, lower activation if in same orientation

The human visual system

low level vision starts in the retina, luminance, intensity, etc. -> optic nerve -> LGN (Lateral Geniculate Nucleus) -> V1 (Primary Visual Cortex)

corpus callosum

major white matter pathway that connects the two hemispheres of the brain

• How good/precise is memory?

o DVD analogy: • Encoding • Record on an electronic disk • Maintenance • Store the DVD in a drawer • Retrieval • Play it back o File drawer analogy • Index files away, searching files o Most people believe that memory records the events of our life much like a video camera o Video memory: "human memory works like a video camera, accurately recording the veents we see and hear so that we can review and inspect them later" not everyone strongly agree witht his but most do

• The effects of the DRM Paradigm

o Deese-Roediger-McDermott (DRM) experiment results • High percentage of recalling words from actual list but also mistaken "recall" of theme words, lower percentage of almost none unrelated words recalled, activating 'chair' concept with swivel, sit, etc even though it wasn't on the list

o Brain in the cloud

o Googling, relying on siri o Don't need to retrieve info from memory as much because of devices, readiness of knowledge, google changing the way we use information o Everything is a click away nowadays, remember where we get it, offloading the need to store all the knowledge o Memorization -> learning how to think, remember where to find it o Socrates had concerns about the advent of written language

Practical applications for cog psy:

o Human factors: cars, cell-phones, web pages, airplanes.. o Does talking on the phone impair driving ability? • Dual-tasking? • Hands engaged? • Hands-free phone better? o Education: understand how ppl learn o Treatment of brain damage: alzheimer's stroke... o Legal system: eyewitness testimonies o Using brain activity as an "eyewitness" • i.e. the murder trial of Aditi Sharma • will neuroimaging tech become the new polygraph test • Neurolaw • Neuroethics

• What does the front of a penny look like?

o Lincoln face right or left? o Anything above his head? o Below his head? o Spot the real penny • Really hard • 8 features of a penny • head of Lincoln, in god we trust, etc. Lincoln faces to right o ask people to draw a penny • people bad at drawing it, draw it many different ways

• Memory error

o Memory is not like a video camera • We often remember on the 'gist' of what we experience rather than the veridical details • Experts strongly disagree with the video camera idea

• Misinformation effects

o Misleading information can affect memory for the actual event o Important for courtroom/eye-witness testimony o "Miss Misinformation" • dr. Elizabeth Loftus wrote many books about misinformation o loftus & Palmer (1974): subjects watcha f ilm on traffic safety and later asked questions about the video o on 1 question, subjects asked: About how fast were the cars going when they hit each other? o Other subjects given same question but with "hit" replaced by "contacted" or "smashed" o Asking how fast cars were goin in video, people got contacted estimated in low 30s, but smashed estimated in upper 40s, question changed memory o Did the question affect memory or other aspects of the accident? • 1 week later asked if they saw broken glass? • For those who gto "smashed - "yes" - 32% • For those who got "hit" - "yes" - 14% o Immediately after viewing slides, subjects filled out a questionnaire • Half subects got "did another car pass the red..stop sign" • Other half "yield sign" • Subjects given misleading information after encoding had false memories for the details of the visual scene • Most people change their memory based on the question they got • Half subjects got stop sign/ half got yield sign o Can implant memories in ¼ or 1/3 of subjects • Lost in shopping mall: planted memory study • Accident at family wedding • Viscious animal attack • Nearly drowned and rescued

Neural Evidence for Early Selection

o Plot electrical wave form with EEG o Around 80 ms, whether they attend or not, when you attend then the signal gets an advantage as early as 80 ms o Reduce neural activity for unattended stimuli o Checkerboard flickers and report whether something changes on left or right side (attending to left or right?) when attending to left side of space more activation in right o In LGN (first stage of visual processing happening beyond retinal system) in thalamus, right LGN shows slightly more activity (remember contralateral) o See this even more in the visual cortex but as early as the thalamus Participants were instructed to pay attention to the signals arriving in one ear, but to ignore signals in the other ear (Panel A). During this task, researchers monitored the electrical activity in the participant's brains, with a special focus on a brain wave termed the N1 (so called because the wave reflects a negative voltage roughly 100 ms after the target). As can be seen in Panel B, the N1 effect is different for the attended and unattended inputs within 80 ms of the target's arrival--indicating that the attended and unattended inputs are processed differently from a very early stage -fMRI study of spatial attentio effects in the lateral geniculate nucleus (LGN)

Change Blindness

o Requires spatial attention o Doesn't pop out o Flickering slowly ̈ Why is it hard to notice the change (initially)? ̈ When motion detection is disrupted, it is very difficult to observe changes to unattended image locations ̈ Brain makes reasonable assumption that things do not change unexpectedly (in the absence of motion cues). ̈ Humans' interpretation of the visual field is much sparser than the subjective experience of "seeing" suggests. - happens in real life too, not only flickering images, people missed the change of person asking for directions

• Memory is a reconstructive process

o We take whatever comes back to mind and fill in gaps o Retrieving a past event (autobiographical memory) engages the same brain mechanisms as imagining a future event o Recalling the past and invisioning the future has lots of overlap, o Past involves reconstruction, probably getting some things right but details may be different o Patients with hippocampal damage show an impaired ability to also envision the future • Less experiential details and spatial coherence

lightness constancy

our brain does not directly perceive the true brightness of objects in the world, but instead compares the brightness of a given item with others in its vicinity -mentally brighten things under the shadow

color constancy

our brain does not directly perceive the true color of objects in the world, but instead compares the color of a given item with others in its vicinity

fMRI study on The Dress

ppl looking at the dress and seeing white/gold had more activation in parts of the brain prefrontal, parietal cortex (white/gold brain working harder) than blue/black

The Deutsch-Norman Selection Mode

q AttributedtoDeutschandDeutsch(1963)andNorman(1968). q Proposedasecondstageofselectionthatoccurslaterintheprocessingsequence. q Late selection model q Selection at this later stage is based on the semantic content of the message q "It is as if attention provides the key that unlocks the gate dividing unconscious perception... from conscious processing. Without this attentional key, there is simply no awareness of the stimulus." (Mack & Rock, 1998) o Information gets through, if sematnic info is relevant to you, you will select it o All info gets processed perceptually, late stage filtering based on which ear its coming in and semantic info

Feature Integration Theory (Treisman)

q During the preattentive stage, features pop out effortlessly. q Search occurs in parallel. q Attention is not required. q During the focused attention stage features are combined together to create object representations. q Search is serial. q Attention is required and serves as the "glue" that binds spatially associated features. q The question of how attention fulfills this role is called the "binding problem" - when you allocate spatial attention to one area, all the feature maps converge -nowhere in your brain where green square is necessarily, map of all these features -"binding problem": we send all these signals out to different parts of the brain to process these features and spatial attention is the glue

The Attenuation Model (Treisman)

q Formulated by Treisman (1964). q Unattended message is not blocked completely but attenuated (i.e., weakened) q The likelihood of information getting through is determined by its threshold. q Threshold = minimum amount of activation required to produce conscious awareness q Important words (e.g., your name, "fire", "help!") have lower thresholds o Instead of blocking it completely, it's more like a filter or faucet so you can adjust the flow o Instead of being blocked completely it's attenuated, o Why does it sometie get through and sometimes doesn't? have to do with threshold o Low threshold - doesn't take much to get noticed This graph shows the thresholds that might exist for three words. The person's name has a low threshold, so it will be easily detected. The thresholds for the words rutabaga and boat are higher, because they are used less or are less important to this particular listener.

Sensory Registers

q Information from the different sensory modalities is initially stored in separate sensory registers. q Iconic memory is a visual sensory store qShort duration (less than one second) q Echoic memory is an auditory sensory store qLonger duration (several seconds) -iconic memory: visual sensory store -flashing image on screen can access it for ms, less than a second -echoic memory: can last for a few seconds, spacing out can repeat back last couple of sentences

Broadbent's Filter Model

q Information is selected on the basis of physical characteristics (e.g., which ear's input to attend to). q The selected information is allowed to pass to later stages where it undergoes further processing. q Unselected information is blocked completely. q An example of an early selection model. o Filter on physical characteristics like which ear is the sound coming in o Applies to visual and other systems too o Blocks out unattented info quite early o Like 2 different channels, one gets thwarted by filter (selective filter), other info gate is open, then processed perceptually

Serial Position Effects

recency and primacy effect -recency: remember words at the end -primacy effect: words at the beginning ̈ Recency effect ¤ Better memory for the last few items on the list ¤ Based on working memory primacy effect only about 3 items recency effect contains abuot 4-5 -info is still in working memory ̈ Primacy effect ¤ Better memory for the first few items ¤ Based on retrieval from long-term memory -primacy effect -motivation at the beginning -more rehearsal, 30 seconds not enough to eliminate the recency effect Another intervening task is needed to do so -3 different curves -immediate recall -30-second unfilled delay is about the same as immediate recall -keep rehearsing items -30-second filled delay -something to distract them -gets rid of recency effect, nothing happens to primacy effect though -everthing except last couple of items are in "long-term" memory § Slower presentation yields better memory for early and middle list items, due to enhanced encoding /rehearsal opportunities. § More rehearsala->Better storage in long-term memory § Presentation rate has no influence on recency effect -more time you have for each word, better you remember (can imagine more, rehearse it more, more robust coding) -slowing presentation -improves beginning and middle but not improving working memory

Object recognition the brain: The dorsal and ventral streams

ventral stream: red and purple region, responsible for infering what we are seeing, temporal (V4-> IT) dorsal stream: travel along to parietal lobe to find where objects are spatial, where?? info travels in parallel through both streams, simultaneously

Problems with Template Theory

when cannot find a perfect match for stimuli in memory ̈ Too many views possible ¤ Would require an implausibly large database of templates stored in LTM

surface reflectance

white paper: reflects 90% light black paper: reflects 10% light if lighting conditions are different bright outside more units reflected, in dim lighting less units of light reflected -same ratio but different # of photons stimulating your retina

Hemispatial neglect

¤ A disorder of attention in which stimuli or parts of stimuli presented to contralesional side are undetected and not responded to. -damage to right pareital area of brain produces failure to attend to opposite side of space, not attending to anything on the opposite side Hemispatial neglect is most often associated with damage to the right parietal lobe Right parietal damage leads to neglect of the left side of space - patients fail to ettend to left side of space -impaired attention to contralegional side of space (left), not just visual space copy half of it, they can see the other side of the space but not attending to it, spontaneous drawing: leaves out eye, hair, clock Neglect - Attention Bias ̈ Attention is biased towards the ipsilesional side ̈ e.g., line bisection task(s) -process things more on the same side -get the lines on the right side of the picture -not fully atrneding to size of horizontal lines, doesn't bisect it corretly, slightly to right side -all of it is going into their visual system but blind to it at a conscious level ̈ e.g., reading a text passage -failure to read words on left side of page ̈ e.g., writing sentences are complete thoughts but gradually skews to the right side of the page (ipsilesional side) Gradual recovery from neglect - patient recovering from stroke, @ 3 months left side is empty, it seems to be improving though across the months -as the brain heals itself and the swelling goes down the attentional system recovers and adapts

Template + transformations approach

¤Matching process involves an initial transformation step: nMental transformations n Rotation n Translation n Scaling nThen compute correlation nAllows for invariance to retinal position, size, and orientation -changes in transformation and translation and scaling presents challenges for template theory Problem: Still not enough invariance (so many fonts so so many different ways to type a)

Slezak figures

Ø Pick one of these animals and memorize what it looks like. Ø Now rotate it in your mind by 90 degrees clockwise and visualize what it would looks like. selzak figures rotated 90 degrees Ø None of Slezak's subjects could identify the new animal produced by the mental rotation Ø Argued that images are intrinsically bound to an structural interpretation

The "central executive" system

̈ A set of control processes involved in the processing of information from the phonological and visuospatial stores ̈ Goal management ¤ Keeping track of goals at various levels ̈ Selection ¤ Choosing which aspects of a particular piece of information to work with ̈ Scheduling ¤ Deciding the order in which to perform a set of operations ̈ These executive control functions are thought to depend on the prefrontal cortex! The "central executive" is actually a complex network of brain regions

Types of illusions Richard Gregory's taxonomy

̈ Ambiguities ̈ Distortions ̈ Paradoxes ̈ Fictions

Analog Representations

̈ Anecdotal evidence: ¤ The experience of imaging feels very much like seeing a picture in one's mind ̈ But can the existence of analog mental images be demonstrated experimentally? Mental rotation ̈ Task: ̈ Are objects on left and right same? Shepard & Metzler's results -reaction time increases linearly with distance as if have image in head that can gradually update analgous to real physical rotation these results are observed even without instruction to use imagery, suggesting that participants spontaneously form mental images and scan them -evidence for analogous theory -can be rotation in picture plane, rotation in depth

Testing as Learning

̈ Being tested for information serves to boost memory. ¤ Retrieval is a form of learning! n Learning effective mental routes to recover the information n Strengthening the memory trace n Weaving new contextual details into the memory ¤ The testing effect n The deep processing needed to take a test helps create longer lasting memories of the material. -retrieval is a form of learning! -like the quizzes we take -must retrieve information -make memory a little stronger update it -testing effect -read a passage -study-study (read twice) then test -study-test (read once then test) then test again -5 minute: better to study twice (cramming) but better retention 2 days after to study-test

Change blindness vs. Inattentional blindness

̈ Both are failures of visual awareness. ̈ Change blindness is the failure to notice that some aspect of a scene has changed. ¤ Focused attention to a given feature is needed to notice that the feature is changing over time. ̈ Inattentional blindness is the failure to notice the existence of an unexpected yet fully-visible item. ¤ Unless an item is distinct enough from its background to "pop- out", focused attention is necessary to perceive it -Change blindness: requires 2 ormore different aspects are changing, search arond until your attention focuses in on the right place or feature -Inattetional blindness: open refrigerator, looking for ketchup and it's right in front of you but can't find it ̈ Inattentional blindness is similar to change blindness in that people fail to 'see' an object. ̈ Unlike change blindness, inattentional blindness occurs while attention is engaged in some demanding task. ̈ Where change blindness reflects an inability to identify how the visual world changes over time, inattentional blindness refers to the failure to notice that a fully- visible item exists at all. One practical take-home message ̈ Our attentional window at any moment in time is quite limited ̈ Many hazards to multitasking

Imagery & Ambiguous Figure

̈ Chambers & Reisberg (1985) ¤ Showed ambiguous figures for 5 seconds and asked for first interpretation ¤ Removed picture, asked people to form a mental image ̈ Results ¤ People were unable to discover a second interpretation from the image ¤ Then drew the figure from memory and could then find the other interpretation ̈ Conclusion ¤ A propositional code may override the imaginal code in some circumstances once they drew it and asked if they could find another interpretation, they could fine it, need to actually look at a picture, not just using your mental images

Context and Memory

̈ Context helps retrieval ¤ Context may be many different things n Other words on list n Environmental cues (e.g., visual, auditory, or olfactory) n Internal mental state at the time of encoding ¤ The more similar the retrieval situation is to the encoding situation, the better retrieval

Mental processes are operations performed on mental representations

̈ Creation ̈ Storage ̈ Retrieval ̈ Use for action ̈ Transformation ̈ Evaluation

Double Dissociation in Support of the Two-Stream Hypothesis

̈ Double dissociations in neuropsychology ¤ Lesion in brain structure A impairs function X but not Y, and a lesion to brain structure B impairs function Y but spares function X ¤ Strong evidence for functional independence! ̈ Optic ataxia ¤ Impairments of visually guided reaching despite normal object recognition. ¤ Lesions of parietal lobe. neuropsychology- studying cognitive processes by studying patients with brain damage Double dissociation: lesion to one part of the brain (damage) impairs one function but not the other if it is found that damage imparis one function not the other and another region does the inverse than evidence for functional independence lesion overlap of ppl who experience optic ataxia, optic ataxia: difficult for patients to reach for objects, not getting right info of where it is in space ̈ What about the flip side? ¤ Impaired object recognition / spared reaching ability ̈ Visual agnosia ¤ Patient D.F. had diffuse damage throughout the ventral stream as a result of carbon monoxide poisoning. ¤ Could not judge even basic aspects of the form or shape of objects. ¤ Could not even describe a line as vertical, horizontal, or tilted. n Normal visual acuity n Normal ability to name objects (when placed in her hand) - Visual agnosia: recognition impairment but normal visual acuity, through other senses could name objects like touch Perception condition: orient index card to line up with slot, could not do it Action condition: putting card in slot, could do it, dorsal intact so has info for action Memory: patient can remember what they did that was correct

Problem #2 for early selection theories

̈ Early selection theory predicts no semantic processing of information from the unattended ear ¤ But experiments have shown that some unattended words do get processed at the semantic level ̈ Anne Treisman's experiment: o Pay attention to right side but left side switches to also picnic items and will finish sentence with unattended ear info because it connects well symmantically with meaning o Not filtered out as we thought

The Propositional Theory's response to mental rotation

̈ Elaborate structural descriptions can explain rotation results. ¤ Angles of features are specified ̈ e.g., Partial description of Shepard & Metzler stimuli: In Pylyshn's own words... ̈ "The representation is not literally being rotated; no codes or patterns of codes are being moved in a circular motion. At most, what could be happening is that a representation of a figure is processed in such a way as to produce a representation of a figure at a slightly different orientation, and then this process is iterated (perhaps even continuously). There are probably good reasons, based on computational resource considerations, why the comparison process might proceed by iterating parts of a form over successive small angles (thus causing the comparison time to increase with the angular disparity between the figures) rather than attempt the "rotation" in one step.

The Self-Reference Effect Rogers, Kuiper, & Kirker (1977)

̈ Encoding information with respect to oneself increases memory ¤ another form of deep processing memorable = relate it to yourself -doesn't really matter how you answer yes or no, just thinking about if it describes you helps you

The relationship between WM capacity and general intelligence

̈ Evidence suggests that general fluid intelligence is closely tied to WM capacity ¤ Individual differences in intelligence are much more strongly correlated with performance on WM tasks requiring maintenance + processing, than on tasks requiring mere maintenance

Let's Test Your Visual Imagery Ability!

̈ Form a mental image of this picture ¤ Which of the pictures on the next slide are part of this picture? ̈ Reed & Johnsen (1975) found that subjects only succeeded 55% of the time ¤ Suggested that visual images often lack sufficient details for direct comparisons of part-whole relationships. ¤ Perhaps subjects don't really store images as "pictures"

Compensating for optical illusions

̈ Front of temple as the architects wanted it to appear ̈ Temple's appearance if it were built without compensations for optical illusions ̈ Temple as actually built with physical corrections to make it appear to the eye as it does Hardly a single straight line or right angle in the Parthenon! For the sight follows gracious contours; and unless we flatter its pleasure by proportionate alterations of the modules—so that by adjustment there is added the amount to which suffers illusion—an uncouth and ungracious aspect will be presented to the spectators. -Vitruvius (27 B.C.)

Recognition by components (RBC) theory

̈ GEONS: geometric elements of which all objects are composed ¤ 36 different different geon shapes sets of constituent elements called geons, briefcase is like geon 1 and 4 Irving Biederman what geons are present in objects? long term memory stores geons and relationships, structural description of object

What is the capacity of STM?

̈ George Miller (1956) ¤ The maximum number of items recalled without error is 7 ± 2 n But what is an item? ¤ Memory span is not limited to a certain number of items per se, but rather by the number of chunks n Chunking: Grouping a series of apparently random items into a smaller number of meaningful segments to enhance recall UFOIBMTNT ̈ Nelson Cowan (2000) ¤ When rehearsal and long-term memory are factored out, our true STM capacity is actually only about 4 chunks -what is an item? a word or a letter, a number or a year -7 +- 2 chunks -UFO/IBM/TNT takes up 3 slots -using long-term memory to lighten load (grouping into UFO) -most people can only maintain about 4 chunks

Levels of Processing (LOP) Craik & Lockhart (1972)

̈ Gus Craik & Bob Lockhart proposed a processing framework for memory ̈ Highly influential view of levels of processing (aka LOP) Evidence for Levels of Processing Craik & Tulving (1975) ̈ Encoding of information into memory is a dynamic process ¤ what we remember is a function of how we process information -not just case we encoutner things in world and store them into memory, the connections we make in our mind makes a difference in how we remember it later -deep processing more elaborate -give participants diff tasks -shallow: is this capital letters? -judging upper or lower case < does it rhyme? < fit in this sentence -retrieve more if deeper processed -hyde and jenkins did a similar study -2 shallow and 2 deeper (find the 'e', count letters vs. how pleasant? learn these)

Sir Francis Galton (1880)

̈ Had subjects use introspection to study mental imagery n Self-reportssuggestedtheycouldinspectmentalimagesaspictures n Exampleinstructionsgiventohissubjects: n "Before addressing yourself to any of the Questions on the opposite page, think of some definite object -- suppose it is your breakfast-table as you sat down to it this morning -- and consider carefully the picture that rises before your mind's eye." n 1. Illumination -- Is the image dim or fairly clear? Is its brightness comparable to that of the actual scene? n 2. Definition -- Are all the objects pretty well defined at the same time, or is the place of sharpest definition at any one moment more contracted than it is in a real scene? n 3. Colouring -- Are the colours of the china, of the toast, bread-crust, mustard, meat, parsley, or whatever may have been on the table, quite distinct and natural?

Attentional deficits following brain damage

̈ Hemispatial neglect ¤ A disorder of attention in which stimuli or parts of stimuli presented to contralesional side are undetected and not responded to. -damage to right pareital area of brain produces failure to attend to opposite side of space, not attending to anything on the opposite side

We almost always use both WM and LTM to accomplish a task

̈ How is memory involved in doing mental arithmetic? ¤ Long-term memory n rules of arithmetic n learned strategies for solving problems ¤ Short-term memory / Working memory n Holds information about the particular problem n Applies the rules and strategies retrieved from long-term memory to the present information n Transiently stores intermediate outcomes and final solution -2 digit multiplication problem -using strategies you learned and hold intermediate terms in short-term memory

Hemispatial Neglect- Attention deficits are not sensory

̈ Impairments manifest in mental imagery ̈ Impairments also apparent at multiple frames of reference ¤ Space-based (environmental) coordinates ¤ Object-based coordinates - relative to the object, the left side will be ignored when attention is zoomed in on object, then the attention is skewed

The process of object recognition

̈ In order to recognize an object, we must: ¤ Represent the physical stimulus in short-term memory (STM) ¤ Find a representation in long-term memory (LTM) that matches the current one taking what you see, representing in transitory state of short-term memory, trying to match it to long term memory, do a search of all the things you know about in the world

Evidence for Levels of Processing

̈ Incidental learning ¤ Deep processing leads to learning, even in absence of an intention to learn ̈ Intentional learning ¤ Usually ensures deep processing will occur ¤ Not necessarily any better than incidental learning with deep processing ̈ Memory is a byproduct of processing -incidental learning: just learning as you go not trying to memorize, recall based on depth of processing -intentional learning: in lab or class trying to use memory strategies, can be worse -memory byproduct of processing (deeper processing = remember better)

Scaling of Mental Images

̈ Kosslyn (1975) ¤ Examined how participants scan and use mental images ¤ Some participants imagine a rabbit next to an elephant ¤ Others imagine a rabbit next to a bee ¤ Then answer questions about the rabbit: n Does the rabbit have whiskers? n Does the rabbit have ears? n Does the rabbit have a beak? ¤ Reaction time to answer is measured Just as in visual images, level of detail in mental images can vary -primed by objectrelationship -zooming in takes time -zooming in and out and changing focus to location to location takes time ̈ It took longer to respond to rabbits paired with elephants than to rabbits paired with bees

Perception of groups - Gestalt principles

̈ Law of Prägnanz: we tend to perceive any given visual array in a way that most simply organizes the different elements into a stable and coherent form 1922 - Max Wertheimer, Kurt Koffka and Wolfgang Köhler ('Prägnanz' is the German word for 'pithiness', which means concise and meaningful. ) Law of Pragnanz: faced with visual stimulus, operating assumption that simplest explanation is the most likely ̈ Figure-ground ¤ Elements are perceived as either figures (distinct elements of focus) or ground (the background on which the figures rest). ̈ Proximity ¤ Things that are close to one another are perceived to be more related than things that are spaced farther apart. ̈ Similarity ¤ Things that are similar are perceived to be more related than things that are dissimilar. ̈ Good continuation ¤ Elements arranged on a line or curve are perceived to be more related than elements not on the line or curve. ̈ Closure ¤ Incomplete objects will tend to be perceived as wholes.

Resolution of the imagery debate?

̈ Lots of evidence for analog visual images ̈ But propositional theory never completely ruled out ¤ Assumes that the mind can rapidly work with extremely elaborate structural descriptions ̈ Can neuroscientific data weigh in on the debate?

Mental representations

̈ Mental representations: 1) are formed in the mind 2) make it possible to think about objects/events in their absence 3) are reliably activated by objects/events in world

Word recognition

̈ 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. (horizontal, vertical lines, curves) ̈ Subsequent layers detect more complex patterns like letters, and then words. -proposed in the 50s -100s or 1000s of neurons distributed over the visual cortex designed to look out for feature detectors, send to letter detectors looking for letter 'c' then sending info over to word detector ̈ Visual words can be recognized with extremely brief presentations (e.g., <40 ms) under the right conditions: ¤ Words that are more frequent in the language are better recognized. n Their "detectors" may have stronger pathways and/or higher starting activation levels ¤ Words that have been recently seen are better recognized, a phenomenon known as repetition priming. n Priming = facilitated processing (e.g., faster reaction time) following a prior encounter ¤ Words in general are better recognized compared to nonsensical strings of letters. - brief presentations to challenge the subject to get interesting data - intuitive properties of word recognition -

The word superiority effect

̈ People are more accurate in recognizing a letter in the context of a word than when the letter is presented in isolation, or in the context of a non-word ̈ Experiment example: Flashed lxvd load Task d?k d?k Performance worse better Flashed d load Task d?k d?k Performance worse better -do better because the context helps you know what letter stirng you just saw with a word ̈ To explain the word-superiority effect, we must add another layer to the network that detects bigrams, or letter pairs. ̈ Here, only some letter O features were detected, but this is compensated for by the higher baseline activity of the CO detector. ̈ The bigram layer helps the system recover from confusion about individual letters. - extra layer: - bigram detector: pair of letters, bigram detector for every possible pairing of letters - not all features, when flashing words, are going to be processed, fill in the blanks with common letter strings, bigrams best guesses ̈ One downside to this organization is that it leads to errors of over-regularization. ̈ Here, the presented stimulus is CQRN but is likely to be misread as CORN. ̈ However, the network's biases usually help achieve correct perception. since CO has a higher baseline state than CQ, system will make a guess that the word is CORN Context effects revisited ̈ A similar mechanism explains why an ambiguous stimulus can be perceived as an A in some contexts and an H in others. - TH is a more common bigram HE is also CA and AT too

The psychology of visual perception: How do we make sense of the visual world?

̈ People resolve ambiguity in everyday situations ¤ To do this, we rely on a few basic principles - can percieve that lines are background - see what fruit is in front of what

The importance of context

̈ Perception is not automatic ̈ Extensive processing is needed to build a coherent percept ̈ Top-down processing occurs involves making inferences based on past experiences and/or surrounding information ¤ Conceptually-driven as opposed to data-driven - always making guesses and assumptions about what is likely to be there in a particular context - bottom up and top down

What illusions teach us about perception

̈ Perceptions are indirectly related to the objective world ̈ Perceptions are guesses (predictive hypotheses) ¤ Often are wrong! ̈ Phenomena of illusions can be used to discover principles of perception ¤ Physiological adaptations n What happens when feature-selective neurons get tired out? ¤ Bottom-up vs. top-down processing n Effects of expectation/context ¤ Cognitive rules and assumptions (heuristics) n Learned from our experience living in a 3D world we use predictions based on lots of factors to make sense of what we are seeing

Geons and object recognition

̈ Perceptually degraded pictures are better recognized if geons are preserved.

Biederman Experiment

̈ Pictures of geometric objects ̈ Priming methodology ¤ Faster to recognize something the second time around (facilitated processing based on prior experience) ¤ Had subjects name objects twice; some rotated ̈ Hypotheses: ¤ Priming occurs because structural description in long- term memory is "active" ¤ Structural description does not change as object is rotated - priming occurs because structural descirption in longer term memory is "active" Structural descrption: which geons and how they are connected ̈ Prediction: If structural description is the same when object rotates, then priming should be unaffected by rotating object between 1st and 2nd trials. ̈ Measure Priming: ¤ Reaction time difference between Block 1 and 2 n For identical and rotated versions of objects for rotated objects if it is view point independent it should be as fast if not, not as fast Biederman's Result • Relativelylittleeffectofrotationonpriming! mostly viewpoint independent 2nd time you see it, much faster when it is rotated there is a little slowing but in general relatively little effect of rotation on priming evidence for viewpoint independent

So is attentional selection early or late?

̈ Psychological and neural evidence for both ¤ Some information may be filtered out at an early stage of processing, while other information may be processed more deeply before it is selected against o Both? o Elements of maybe all 3 models

Geons & structural descriptions

̈ Relations are spatial and approximate e.g. Ice-cream = sphere on-top-of cone bucket vs. mug geons related spatially influences what object it is bucket Geon #4 on-top-of Geon #2 mug Geon #4 Attached-to-the-side-of Geon #2

The Baddeley & Hitch (1974) model of working memory

̈ Replaced the concept of a unitary "short-term store" with a multi-component "working memory" system -short term memory is not just one thing -system with multiple storage components that feed into a processing component Phonological loop: holds auditory, verbal information -visual-spatial buffer: holds visual, spatial info in mind -sends to central executive, chooses which one is important , coordinate process, chooses to continue to loop or if asked to reogranize it in an order, helps with that

Template Theory

̈ Representations are mental images ¤ Those in LTM are templates \ ̈ Matching process is correlational ¤ Overlay input and template ¤ Highest correlating template wins See stimuli (cat) search memory for a match (cat out of other animals) ex. check reader

Distortions

̈ Roger Shepard's "Turing the Tables" Illusion ̈ The Müller-Lyer illusion (1889)

Taxonomy of memory

̈ Short-term memory (a.k.a. working memory) ¤ Maintains and manipulates information relevant to one's current goals ¤ NOTE: sometimes the term STM is reserved for simple information maintenance, whereas WM is used to imply maintenance plus manipulation n However, we will use the terms STM and WM interchangeably ̈ Long-term memory ¤ Holds the stored record of prior experience ¤ Declarative memory = memories that can be verbally expressed n Episodic memory n Memory for specific life events (with spatial and temporal context) n Semantic memory n Memory for facts and general knowledge (acontextual) ¤ Nondeclarative memory = memories that cannot be verbally expressed n Procedural memory n Memory for skills and habits; demonstrated by doing (e.g., riding a bike) -Declarative memory -can declare or verbally express -Episodic memory -episodes/events in life ex. h.s. graduation, wedding -semantic memory -facts, Trump is president, -nondeclarative memory -procedural memory -skills, tying a shoe

Spacing effects

̈ Spaced practice is better than massed practice ¤ Cramming for exams is bad! n Unless you have no desire to remember the info after the exam. ¤ Spacing of study sessions leads to better long-term retention of the material ̈ Why? ¤ In massed practice, the context at encoding is similar for all repetitions ¤ In spaced practice, the context will differ on each repetition ¤ Some of this context is likely to match what is encountered at retrieval time (i.e., more potential "retrieval paths") comes down to context, massed practice (mind mood environment all the same), when spaced context changes, as things differ more and more contextual variability and retrieval paths

Dissociation between phonological loop and visuo-spatial buffer

̈ Stroke Patient P.V. ¤ Damage to left hemisphere temporal lobe and frontal lobe regions ¤ Normal intelligence ¤ But unable to repeat back even short sequences of spoken digits ¤ And unable to perform mental arithmetic P.V. -impairment that damages phological loop but not visual=spatial -mental arithmetic requires thinking about numbers and keeping track of things

The Generation Effect Slamecka & Graf (1978)

̈ Subjects learn pairs of words, either read them: rapid-fast, lamp-light ̈ OR generate the second item in the pair: rapid-f_ _ _ , lamp - l_ _ _ _ ̈ LATER: Given a cued recall test, and people do much better with generation than mere reading ̈ HINT: How to study for exams? -retrieve associative letter -one condition: given pairs of words -second condition: generating the second item yourself (strengthens the learning) -> generation effect ensures deep encoding -cued recall: give rapid and ask for other, generating associative itself much better

Patient E.L.D. (Hanley et al., 1991)

̈ Suffered stroke to right hemisphere frontal/temporal lobe region ¤ Reported difficulties in finding her way home, and memory problems for unfamiliar material ̈ Severe deficit in visuospatial memory ¤ Impaired at Corsi blocks (spatial span task) ̈ Normal auditory short-term memory -spared phonological loop but damage visio-spatial -looking at side without number, has to repeat it back, couldn't do it

Feature Integration Theory

̈ Suggests that we have distinct feature maps ¤e.g., orientation, shape, color, size ¤Each map has info about the location of its feature nLoaded without attention nIn an isolated feature search, you only have to consult your feature map. -we have distinct feature maps ̈ In a combined feature search we must bind information from 2 (or more) maps. nBinding the 2 maps requires attention, which takes longer. need to find presence of 2 features (oval and diagonal line) -shape and line information

What are not mental images?

̈ Symbolic or linguistic representations ̈ e.g., Structural description • ListofFeaturesandRelationships • e.g., Dog: don't really need imagery to answer questions about a dog Pointy ears on-top-of head Head on-top-of body Four legs beneath body Fur covering ears, legs, body

Kosslyn's image scanning experiment (1978)

̈ Task: 1) Memorize map 2) Map taken away 3) Focus attention on named location 4) Hear other location 5) Press button when attention at 2nd location Results of image scanning experiment ̈ "Scanning" farther takes longer ̈ Support for analog representation hypothesis ¤ Mental images are internal representations that operate in a way that is analogous to the functioning of the perception of physical objects n Functional equivalence

Ambiguities

̈ The Necker Cube (1832) ¤ Example of a "bistable" perception - toggle in your mind which way the box faces

Does the Müller-Lyer illusion depend on experience?

̈ The carpentered world hypothesis: ¤ Our perception of this illusion is due to our extensive life experience using corners and angles as distance cues ¤ Country-dwelling Zulu people who live in round huts with rounded doors and windows DO NOT experience this illusion ¤ City-dwelling Zulus are fooled by the illusion like everyone else

Problem #1 for early selection theories

̈ The cocktail party effect ¤ e.g., People notice when their own name is spoken at a noisy party, even when they're not paying attention ¤ Doesn't have to be your own name; anything you're interested in can capture your attention -shadowed ear: "Mary had a little lamb" -unattended ear: " [john smith] you may stop now" Result w/o own name: 6% notice w/ own name: 33% notice

The phonological loop and visuo-spatial buffer

̈ The phonological loop (a.k.a. articulatory rehearsal loop) maintains linguistic information in a phonological form ¤ e.g., rehearsing a phone number ̈ The visuo-spatial buffer (a.k.a. visuo-spatial sketchpad) aids in the temporary maintenance of visual and/or spatial information ¤ e.g., glancing at a map and then holding the routes in mind while looking at a fork in the road

The problem of inverse optics

̈ The world is 3-dimensional ̈ The retina is 2-dimensional ̈ How can the brain reconstruct the 3D world based on a 2D retinal image? ¤ It can't! (at least not perfectly) ̈ The problem is fundamentally ill-posed ¤ There are an infinite number of 3D worlds that could produce the same 2D image ̈ A round object appears on the retina... ¤ Is it small and nearby or large and far away? ¤ Is it a disk, a sphere, a cylinder, or a cone? ¤ There is no way for the eye to know! view of impossible object, but in the mirror is the possible, actual object

Basic properties of geons

̈ They are sufficiently different from each other to be easily discriminated ̈ They are view-invariant (look identical from most viewpoints) ̈ They are robust to noise (can be identified even with parts of image missing)

Carmichael, Hogan, & Walters (1932!)

̈ Verbal labeling of visual materials ¤ Participants were shown simple figures with one of two verbal labels ex. sun vs. ship's wheel ̈ Later participants were asked to draw items seen ̈ Participants distorted the images to fit the labels ̈ These results support the idea that images may be stored propositionally, not as original analog image

Encoding and Episodic Memory

̈ We remember different kinds of things: ¤ Specific events or episodes n Can often later recollect the source (context) of the information n But sometimes we later only experience a sense of familiarity ̈ How do we learn? ¤ Maintenance rehearsal (a.k.a. item-specific rehearsal) n Simply focus on the to-be-remembered items themselves ¤ Elaborative rehearsal n Thinking about what the to-be-remembered items mean and/or how they're related to each other and to other things you know n Why is this better? -specific events or episodes -not only what happened, how were you feeling, who are you with, etc. (what is on the list? is not recollection necessarily unless they remember specifics) -only sense of familiarity (don't know where i know you from but familiar) -elaborative rehearsal: associating it with other info, making it more memorable for you

Theories of attentional selection

̈ What determines which aspects of our moment- to-moment experiences rise to the level of conscious awareness?

Feature Nets

̈ 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. - nodes looking for features, but network knowledge of the dictionary depends on how often combinations get stimulated ̈ McClelland and Rumelhart's (1981) model of word recognition included two additions: ¤ Excitatory and inhibitory connections between detectors. ¤ Top-down connections from words to letters and letters to features. -80s of computational modeling - thinking you saw TRIP will send inhibitory singals to thinking you saw the word TRAP, diminish the likelihood of other combination -works for bigrams too

Electroencephalography (EEG)

• Because fMRI only measures blood flow, it does NOT provide precise info about the timing of neural activity. • EEG can record electrical activity from large populations of simultaneously active neurons at the scalp with millisecond resolution. • EEG is a direct measure of neural activity. • EEG systems are much cheaper than MRI scanners

Transcranial Magnetic Stimulation (TMS)

• Brief powerful electrical charge is created in coil • Creates a 1.5-2.0 Tesla magnetic field capable of inducing eddy currents in tissue 1-2 cm deep - Disrupts normal neural function by adding noise - In essence, TMS creates a temporary virtual patient - Unlike fMRI and PET, TMS can assess the causal influence of a region on behavior. - Unlike naturally-occurring lesions, TMS gives researchers more control, better temporal resolution, and the ability to create multiple virtual patients in the same individual.

The Brain: Somatosensory cortex

• Cortical representations of information is weighted by "importance"

The Brain: Motor cortex

• Cortical representations of information is weighted by "importance" -asymmetry

Dichotic listening / Shadowing tasks

• Dichotic listening (listen to what's in your left ear) can play something in right ear, what gets through? • People almost entirely block out info from ear they don't pay attention to • Can say yes or no if they hear the voice, changes of the gender of the voice, but not change of language • Ability to filter out auditory info from one space to another is pretty good What gets through? What happens to unattended message? à Not much, we seem to remember mostly low-level information (whether or not there is a human voice, changes in gender of voice, but not a change in language) à The same word can be repeated without even being noticed

Event Related Potentials (ERPs): Limitations

• Limited spatial resolution, despite high temporal resolution - Poor anatomical localization, but great ability to determine precise timing of neural events • Skull and brain tissue distort electrical fields • Largely blind to subcortical activity(too deep to measure on the scalp) • But some ways to overcome these limitations...

Neural impulses

• Neurons process information by electric impulses that travel down the axon • When the input to the dendrites reaches a threshold level, the neuron fires - Sends an electrical impulse known as an action potential - Action potential propagates along axon due to the entry and exit of ions through channels in the cell membrane

fMRI: Pros

• PROs - Good spatial resolution (1- 3mm3) allows precise localization of brain activation - Lots of information represented within spatial patterns of brain activity - Non-invasive (no known harms to subjects) - MRI scanners are widely available at medical centers and research universities.

Positron Emission Tomography (PET)

• Subjects injected with radioactive isotope, which emits positrons • Positrons collide with electrons, emitting two photons (gamma rays) in opposite directions • Detectors surrounding brain register simultaneous photons and compute likely source • Neural activity -> increased metabolic demanda->local increase in blood flow the active region injected in blood stream Radioactive Carbon Oxygen, because unstable, decays and emits positron, when collides with free electrion, gives off 2 photons (light energy) • Compares regional cerebral blood flow (rCBF) between cognitive states (experimental conditions) • Integrates signal over 45-60 sec • Need to wait a number of half-lives before next injection

Mental imagery can be sufficient to trigger context reinstatement

• Subjects learn words in a distinct room; tested in 1 of 3 conditions: 1) Same context 2) Different context 3) Different context, but imagine encoding context ØResult: imagining the encoding context almost as good as being there -say you had to take final exam in different room, isn't too bad, can imagine yourself in context -same context tested than leraned -different context tested than leraned -different context tested than learned but imagine yourself in context you learned, it's better

Example of a simple TMS experiment

• TMS coil placed over target brain region • Stimulation applied at different points in time relative to stimulus onset • Cognitive failures recorded

The Neuron

• The basic parts of a neuron are: - Dendrites, which detect incoming signals (input) - The cell body, which contains the nucleus and cellular machinery (decision making) - The axon, which transmits signals to other neurons (Transmit within neurons) -axon terminal (Transmit across neurons)

The First Brain Imaging Experiments

• The case of Michele Bertino, a 37-year-old farmer who had a wide skull fracture (Mosso, 1880). • The fractured skull bones were removed and a 2 cm cerebral mass was exposed in the right frontal region. • When patient was asked to multiply 8 x 12, brain pulsations increased.

The First Brain Imaging Experiments

• The case of Michele Bertino, a 37-year-old farmer who had a wide skull fracture (Mosso, 1880). • The fractured skull bones were removed and a 2 cm cerebral mass was exposed in the right frontal region. • When patient was asked to multiply 8 x 12, brain pulsations increased. [In Mossos experiments] the subject to be observed lay on a delicately balanced table which could tip downward either at the head or at the foot if the weight of either end were increased. The moment emotional or intellectual activity began in the subject, down went the balance at the head-end, in consequence of the redistribution of blood in his system. -- William James, Principles of Psychology (1890) delicate balancing, when cognitive thinking, more blood flow, would tip the table Key Insight: Increased brain activity leads to increased blood flow

Representations

• Version of something in a different format - e.g., maps as representation San Francisco (google image) The represented world Map of San Francisco (The representing world)

Synaptic neurotransmission

• When the action potential reaches the axon terminal, it causes the release of neurotransmitters into the synapse - space where the axon terminal contacts the dendrite - each neuron has ~1,000-10,000 synapses • Neurotransmittersbindto receptors on the post-synaptic dendrite and influence its activation state