Psychology 258 Midterm 1 Summary Sheet PDF

**PSYCH 258 Midterm 1 Summary Sheet** *15MC, 2 Blanks, 2SA* **Lecture 1 -- Introduction** *Indirect Inferences* - A main challenge in cognitive psychology is operationalizing -- turning abstract conceptual ideas into measurable observations. - Necessary because we cannot directly me...

**PSYCH 258 Midterm 1 Summary Sheet** *15MC, 2 Blanks, 2SA* **Lecture 1 -- Introduction** *Indirect Inferences* - A main challenge in cognitive psychology is operationalizing -- turning abstract conceptual ideas into measurable observations. - Necessary because we cannot directly measure someone's mental processes. - Cognitive researchers look to make indirect inferences about mental processes based on things that are accessible ∴ measurable. - Example: determining the temperature of an oven at a before it reaches the set temperature by rotating the dial back until you hear a click at the current heat. *Typical Experimental Approach* - The classical cognitive approach involves: - Measuring observable behaviour. - Example: reaction time, accuracy, etc. - Making inferences about underlying cognitive activity. - Considering what the behaviour says about how the mind works. **Lecture 2 -- Introduction Continued** *Rise of Behaviourism -- Objections to Studying the Mind* - Watson found two problems with psychological study approaches from previous researchers: - Extremely variable results from person to person issue of reliability -- consistency of a measure. - Results were difficult to verify due to unobservable mental processes issue of validity -- does the test measure what it should measure? - Watson proposed a new approach (along with Skinner): - Behaviourism -- technique that studies directly observable behaviour instead of the mind. - Behaviourists saw the mind as an inaccessible 'black box'. They thought it couldn't be objectively studied as cognitive processes cannot be directly measured. *Behaviorism -- Watson and Rayner* - Little Albert experiment demonstrated classical conditioning -- the process where an automatic, conditioned response is paired with specific stimuli. - Baby learned to fear a rat after multiple exposures to it being paired with a loud noise. *Behaviourism -- Skinner* - Skinner studied the relationship between stimuli and response, contributed to operant conditioning -- learning method using S-R associations and reinforcement principles to modify behaviour. - Behaviour that is rewarded (reinforced) is more likely to be repeated. - Behaviour that is punished is less likely to be repeated. *Behaviourism -- Parsimony* - Principle of Parsimony (Occam's Razor) -- the simplest scientific explanation for evidence is preferred. - Strength of conditioning explanations as simple concepts can predict a wide range of behaviours across many species. - Did not involve 'guessing' what was happening in an organism's mind or self-report. *Rise of Cognitivism* - Cognitivists countered behaviourists in believing: - **Mental processes can be studied scientifically using clever experiments to generate empirical evidence.** - **It is necessary to consider what is happening in the mind to get a more complete understanding of behaviour big picture.** - Humans are NOT a tabula rasa blank slate. *Cognitivism -- Tolman's Rat Maze Study* - Rats had to learn to find a reward in an armed maze. - Behaviourists thought rats learned to navigate the maze through reinforcement of S-R mappings no higher-level knowledge of maze layout. - Example: they learned an S-R association to turn right and get food and that is the only way they can navigate to the goal. - Turning right to get food should occur frequently as it has been reinforced, turning left should not as it has not been. - However, rats performed well when starting in unfamiliar locations of mazes they had previously learned to successfully navigate **suggests cognitive map!** - Cognitive Map -- mental representation of one's physical environment. - Rats had the ability to more flexibly navigate their environment than observable behaviour alone! - Shows latent learning -- learning that has occurred but is not necessarily evident from observable behaviour. *Cognitivism -- Skinner vs. Chomsky's Language Acquisition* - Language Acquisition -- process where humans gain the capacity to perceive and comprehend language. - Skinner believed language acquisition could be explained through operant conditioning alone (no need to examine mental processes): - Example: kids imitate words they hear, using words correctly gets rewarded ∴ more likely to use words correctly in the future. - Chomsky believed language must be partially determined by factors operant conditioning cannot explain genetic predispositions. - Example: kids say things they have never heard, and incorrect things that haven't been reinforced. *Cognitivism -- Paradigm Shift* - Paradigm Shift -- major change in perspective, approach, or underlying assumptions. - Examples: Heliocentric universe, DNA discovery, etc. *Cognitive Revolution -- Information-Processing Approach* - Cognitive Revolution -- intellectual movement producing a paradigm shift away from S-R relationships (behaviourism) and towards explaining behaviour in terms of the mind. - Information-Processing Approach -- studying the mind with insights about digital computers. - Can studying computers can give insight into human cognition? Can studying human cognition can allow to make better computers? - Early computers processed information in stages, which raised questions about parallels with the human mind: - How much info. can the mind absorb? - Do we have capacity limits? - Can the mind selectively attend to only some incoming info? - Different from what computer does! *Information-Processing Approach -- Dichotic Listening Task* - In Cherry's task, subject wore headphones and were given Message A in their left ear, and Message B in their right. - Subjects asked to shadow one message. - **Only able to consistently repeat what was in the attended ear.** - Early demonstration that objective measurements of mental processes were possible! - Studied selective attention can filter out the content of one message over another. - Cocktail Party Effect -- ability to focus on one stimulus while filtering out others. *Information-Processing Approach -- Broadbent's Filter Model of Attention* - Flow diagram representing what happens as a person directs attention to one stimulus. - **Input Filter Detector Memory** - Unattended information does not pass through the filter. - The message the person attends to is further processed by the detector and then stored in memory. - Top-down process. - Sensory Memory -- briefly holds incoming information, transfers it to next stage. - Filter -- identifies attended message based on physical characteristics and passes it on to the next stage. - Detector -- processes all information passed along by the filter to determine higher-level characteristics of the message. - Memory -- receives output of detector, holds information in STM for 10-15 seconds and then may transfer it to LTM. *Cognitive Revolution -- AI and Information Theory* - Artificial Intelligence -- making a machine behave in ways that would be called intelligent if a human were so behaving. - Newell and Simon created a program that applied rudimentary logic to creating mathematical theorems potential for AI to 'create'. *Process Models* - Process Models -- represent the processes involved in cognitive mechanisms, with boxes usually representing specific processes and arrows indicating connections between them. - Breaks down concepts into components. - Example: Input Sensory Memory STM, Rehearsal Output, LTM. - Example: LTM Episodic (life events), Semantic (facts), Procedural (physical actions, muscle memory). *Structural Models* - Structural Models -- representations of a physical structure, mimic the form/appearance of a given object. - Many cognitive neuroscience models take this form. - Range from very simple to complex. - Example: plastic model of the brain, visual system map. **Lecture 3 -- Cognitive Neuroscience** *Cognitive Neuroscience* - Cognitive Neuroscience -- study of the physiological basis of cognition. - Considers the nervous system and the units that comprise it. - Example: brain. - Examined from various angles and points of view for greater understanding. *Early Conceptions of Neurons* - Interconnections of neurons was referred to as a continuous "nerve net". - Like a highway with connecting streets for continuous communication. - Proved wrong by Golgi staining methods showed neurons and synapses. - Cajal then argued the neuron doctrine -- individual nerve cells transmit signals and are not continuous with other cells. *Signal Transmission in Neurons* - Neurons -- cells specialized to create, receive, & transmit information in nervous system. - Communicate via electrical and chemical means. - Cell Body -- contains mechanisms to keep cell alive. - Axons -- fluid-filled tubes that transmit electrical signals to other neurons. - Dendrites -- multiple branches off the cell body that receive information from other neurons. - Impulse transmission occurs from dendrites to axons. - Synapse -- space between axon of one neuron and the dendrite or cell body of another. - Synaptic vesicles open to release neurotransmitters when the AP reaches the end of the axon. - Neurotransmitters -- chemicals that affect the electrical signal of the receiving neuron, cross the synapse and bind with receiving dendrites. *Action Potentials* - Action Potentials -- all or nothing electrical impulses used for signalling purposes. - Primary communication method in nervous system. - Travel along axon of presynaptic neuron to dendrite of postsynaptic neuron. - Na+ ions come in to depolarize, K+ ions come out to repolarize, hyperpolarize, and back to resting state. - Measured with microelectrodes that pick up an electrical signal when placed near axons. - Active for about 1 second. - Measures firing rate -- action potential frequency within a time interval. - Low intensities slow firing, high intensities fast firing. - Size does NOT matter all or nothing. *Feature Detectors* - Feature Detectors -- neurons tuned to respond to specific low-level stimulus properties. - Typically associated with a basic physical property. - Example: horizontal or vertical lines, certain frequencies. *Experience Dependent Plasticity* - In Blakemore and Cooper's experiment, kittens were selectively raised in tubes with either horizontal or vertical lines. - Kittens never exposed to horizontal lines couldn't perceive them later in life when finally exposed to them, and vice versa. - Effects apparent in behavioural and neural responses! - Related to feature detector development: - If relevant stimuli are not present in environment, feature detector never develops. - Use it or lose it plasticity! - Example: intonation matters less in English, so we don't develop it as compared to tonal languages. *Neurons Responding to Complex Stimuli* - We perceive objects in an order that moves from lower to higher areas of the brain. - Hierarchical Processing -- perceiving objects from lower (simple) to higher levels of complexity. - Example: V1 for edges and lines, V2 for shapes, V4 for objects, IT for faces. *Mirror Neurons* - Mirror Neurons -- neurons specialized for emulating what other people are experiencing doing, feeling, etc. - Some fire both when doing an action yourself and when watching others do so. - Important implications for learning and behaviour: - Example: tool use evolutionary advantage, empathy strategic judgments, theory of mind autism implication (lower emotional understanding), language acquisition, understanding other's intentions, 'contagious behaviours' (yawning, vomiting, etc.). *Neural Coding* - Specificity Coding -- specific stimulus representation where a single neuron codes for one representation. - Example: one neuron responds to each specific face. - Population Coding -- a representation of an object where pattern of firing for many neurons occurs. - Example: lots of neurons correspond to each specific face. - There is high activation of some and moderate/low activation of others. - Sparse Coding -- an object is represented by the firing pattern of a small group of neurons, with most of them remaining silent. - Example: some neurons correspond to each specific face. **Lecture 4 -- Cognitive Neuroscience Continued** *Localization of Function* - Localization of Function -- specific functions are served by particular brain areas. - Cognitive functioning breaks down in predictable ways when brain areas are damaged. - Example: blindsight can't see, but higher visual areas are intact. - Cerebral Cortex -- thick layer covering the brain that contains mechanisms responsible for most of our cognitive functions. *Localization Determined by Neuropsychology* - Study Tip: BPs and Workers' Comp. - Broca's Area -- language production area in the frontal lobe. - Wernicke's Area -- language comprehension area in the temporal lobe. - Double Dissociations -- occur when damage to Part A of the brain causes Function A to be impaired, while Function B is maintained, and vice versa. - Evidence for localization of function. *Localization Determined by Neuron Recording* - Taso's study used single-cell recording -- measured the response of individual neurons. - Found an area in animals analogous to the human Fusiform Face Area (FFA) -- a temporal lobe region that responds to faces. - FFA abnormalities believed to cause prosopagnosia -- a condition where people are unable to recognize faces. *Localization Determined by Neural Stimulation* - Parvizi placed electrodes on the cortex of a patient who was having neurosurgery to test electrical stimulation of the FFA: - Distorted how the patient perceived faces blurry, psychedelic-like. *Brain Stimulation -- MRI & fMRI* - Magnetic Resonance Imaging (MRI) -- technique using magnetic fields and radio waves to generate anatomical images of body tissue. - Static, anatomical. - Functional Magnetic Resonance Imaging (fMRI) -- uses magnetic fields and radioactivity to measure change in the Blood-Oxygen-Level-Dependent (BOLD) signal, which is correlated with cognitive activity. - Active neurons require oxygen and glucose, which changes the magnetic properties of surrounding blood more blood goes to active areas. - This change is detected in the BOLD signal and is used to infer changes in neural activity correlate. - 'Draws' boundaries based on voxels -- 3D pixels superimposed onto a brain scan. - BOLD signal estimates changes in the average activity within specific voxels overlapping with brain region of interest. *Localization Determined by Neuroimaging* - Parahippocampal Place Area (PPA) -- area in the temporo-occipital cortex that responds specifically to places. - Damage can disrupt ability to perceive indoor and outdoor scenes. - Object identification is still intact! - Extrastriate Body Area (EBA) -- area in the occipital lobe that responds specifically to pictures of or parts of the body. - Huth's study showed subjects video clips while scanning neural activity with an fMRI. - Stimuli was categorized into various groups of nouns and verbs. - Example: women, talking, desert, city, bison. - Analyzed stimulus categories to see if any one region was reliably active in all the clips that included talking, etc. - Found many associations between specific brain regions and stimulus categories. - Similar stimuli can also be processed in different ways depending on context. - Example: talking activates several brain regions. *Distributed Representation* - Distributed Representation -- notion that many complex behaviours involve coordinated activity across different parts of the brain. - Example: playing a violin requires the premotor cortex to plan the movement and the motor cortex to do the movement. - Depending on the task demand, various neural regions may be needed to help process feature detectors, emotional reactions, etc. - Example: recognizing a face involves FFA, occipital cortex, amygdala, frontal lobe, and STS. *Evidence of Localization of Function and Distributed Representation* - They can be complimentary; fMRI demonstrates evidence of both: - Specific brain areas are responsible for perception of specific stimuli. - Maximum activity occurs in separate areas of cortex. - Evidence of widespread activity that stretches across cortex for processing various stimuli. **Lecture 5 -- Cognitive Neuroscience Continued** *Positron Emission Tomography (PET)* - Positron Emission Tomography (PET) -- early functional brain imaging technique involving injection of radioactive 2-DG that is rapidly taken up by active cells until it gradually breaks down. - 2-DG acts like glucose allows a map of radioactive dye to be made, which correlates with neural activity. - Estimates neural activity via blood flow. - **High spatial resolution, low temporal resolution opposite of EEG.** - Less used now due to invasive radioactive dye. *Transcranial Magnetic Stimulation (TMS)* - Transcranial Magnetic Stimulation (TMS) -- imaging technique using a magnetic field and an electrical current to modulate brain activity at specific sites. - Used to decrease or increase firing. - Can create virtual lesions -- temporary impairments that serve as an ethical manipulation of neural function. - **Allow causal inferences!** - Repetitive TMS (rTMS) can produce longer-lasting changes in neural activity, but safety and efficacy debated. *Four Principles of Neural Networks* - There are complex structural pathways (networks) that form brain's information highway. - Pathways can strengthen or weaken due to experience, stress, etc. - Within the structural pathways, there are functional pathways. - These networks operate dynamically mirror dynamic nature of cognition. - Amount and type of information is constantly changing. - There is a resting state of brain activity (Default Mode Network), so parts of the brain are always active even with no or limited cognitive activity. *Default Mode Network (DMN)* - Default Mode Network (DMN) -- a network of brain regions that are active at rest. - Associated with mind wandering -- thinking about things that aren't in our immediate environment. - Mind wandering decreases with age (less frequent in older people). - Older brains may be less active and make less spontaneous connections or have better control. - Evolutionary advantage! *Types of Connectivity* - Structural Connectivity -- physical connections in the brain. - Measured with DTI (TWI). - Functional Connectivity -- inferred based on the extent to which activity in multiple areas is correlated. - Resting-State Functional Connectivity -- procedure for determining whether two areas are functionally connected. *Assessing Functional Connectivity* - Use task-related fMRI to determine seed location -- brain location associated with a specific task. - Measure resting-state fMRI at seed location. - Measure resting-state fMRI at test location different location. - Calculate correlation between seed and test location responses to assess degree of functional connectivity. *Common Functional Networks* - Visual -- vision and visual perception. - Somato-Motor -- movement and touch. - Dorsal Attention -- attention to visual stimuli and spatial location. - Distributes attention in a meaningful way. - Executive Control -- higher-level cognitive tasks involved in working memory and directing attention during tasks. - Salience -- attending to survival-relevant events in environment. - Example: fire alarm instead of textbook. - Default Mode -- mind wandering, cognitive activity related to personal life, social functions, monitoring internal emotional states. *Assessing Structural Connectivity -- DTI* - Diffusion Tensor Imaging (DTI) -- also known as Track-Weighted Imaging (TWI), uses MRI technology to map out major tracts in the brain. - Different pathways for different people. - Example: colour synesthesia. - Used to understand how differences in structural connectivity between different brain regions are related to various factors. - Tracts -- bundles of axons. **Lecture 6 -- Perception** *Perceiving Objects and Scenes* - Feature detectors play a role. - We often make mistakes. *Basic Perception Characteristics* - People can have different perspectives ∴ see, hear, feel different things when attending to the same stimuli. - **Perception is constructed and often subjective.** - Text on images, colour memory, being a night owl/early bird, etc. can affect perception. *What is Perception?* - Perception -- experience resulting from stimulation of the senses. - Can change based on available information. - Involves active and constructive processes, drawing on higher level cognitive abilities to resolve ambiguities prior experience, expectations, biases, etc. - Tends to occur in conjunction with actions. *AI Perception Study* - Researchers used a 'psychedelic toaster' to "distract" image recognition software. - Computer-generated pattern was more salient to image recognition than real objects. - Was not fooled by real objects. - Humans do not get instant feedback like computers. *The Nature of Human Perception* - Attempts to create artificial machines with perceptual abilities have been unsuccessful. - Frequently had problems that couldn't be solved 3D to 2D world. - This is because human perception is constructed and ambiguous. *Difficulties in Designing a Perceiving Machine* - Inverse Projection Problem -- task of determining the object responsible for a certain image on the retina. - Complex as any given 2D object formed on the retina could be formed by many options of 3D objects in the environment. - Objects are frequently hidden, obscured, blurred, etc. - Multiple information sources or cues are often considered in perceptual interpretations. - Objects can look different from different viewpoints, lighting, etc. - Humans use cognitive mechanisms to solve these: - Example: viewpoint invariance -- recognizing things as equivalent from different perspectives. *Bottom-Up and Top-Down Contributions* - Bottom-Up Processing -- perception starts with the senses as energy or chemicals are registered on receptors, comes from environmental stimuli. - Focus of direct perception theories. - Examples: pain receptors, hair cells in ear. - Parts are identified and put together, then recognition occurs. - Top-Down Processing -- perception starts with the brain knowledge, experience, expectations shaping what is perceived. - Focus of constructive perception theories. - Examples: you think a needle will really hurt since it did last time. - Probability plays a role prior experience. - Example: a blurred picture of a street with blobs is likely to be cars instead of cows. - **Both bottom-up and top-down mechanisms tend to be involved in perceptual experiences.** *Speech Perception* - Speech perception can be influenced by multimodal information. - How humans typically process. - Audiovisual Speech Perception -- visual information influencing speech perception. - Example: McGurk Effect -- one acoustic signal is played with a video saying 'ba-ba' that shows lip movements for 'fa-fa'. - Visual input changes perception of the sound! - Speech Segmentation -- dividing speech into the constituent words contained within the acoustic signal. - Even though native speakers of a language leave little to no pause between words, other native speakers can easily identify when one word stops and another ends. - Even with pitch, slurring, and mumbling variations. - Foreign languages rather sound continuous and unbroken. **Lecture 7 -- Perception Continued** *Conceptions of Object Perception* - Theory of Unconscious Inference -- some perceptions are the result of unconscious assumptions and inferences we make about the environment based on prior knowledge and personal experience (top-down). - Likelihood Principle -- we perceive the world in the way that is most likely based on our past experiences. *Gestalt Principles of Perceptual Organization* - Structuralism -- reductionist view of psychological processes, perception is additive combinations of various basic sensations. - Breaks down perception into its building blocks. - Gestalt -- rejected structuralism, perception is a product of the mind grouping patterns according to laws of perceptual organization. - The whole is more than the sum of its parts! - Phi Phenomenon -- when still images are perceived as being in continuous motion when rapidly alternated across different locations. - Evidence against structuralism as there is something perceived that is not present in a building block motion. - Principle of Good Continuation -- lines tend to be seen as following the smoothest path possible. - Biased due to probability. - Law of Pragnanz -- every stimulus patten is seen so the resulting structure is as simple as possible. - Conforms to things we see in everyday life. - Proximity Principle -- things close together in space tend to be grouped together. - Similarity Principle -- similar things tend to be grouped together. *Physical Regularities* - Many physical regularities occur in the environment, which influence how our perceptual systems function. - Example: Oblique Effect -- vertical and horizontal lines are perceived easier than lines of other orientations. - Likely because vertical and horizontal lines are common in many environments more feature detectors tuned to them. - Example: Light From Above Assumption -- because light comes from above in many natural and unnatural environments, we get expectations of how shadows will form on objects. - Relative locations of shadows lead us to make assumptions about object form. *Semantic Regularities* - Semantic Regularities -- characteristics typically associated with different types of scenes. - Often relate to actions or activities commonly undertaken in the scenes. - Example: kitchen usually have tools and appliances for cooking. - Scene Schemas -- knowledge of what a given scene ordinarily contains. - In Palmer's study, subjects had to identify objects consistent or inconsistent with their expectations for what would be found in each room top-down. - Identified consistent objects faster context helps us interpret. - Affected scanning patterns and meaning extracted. - Higher fixation on objects out of context. *Bayesian Inference* - Bayesian Inference -- estimates of the probability of an outcome are influenced by the prior probability (expectation based on prior experience) and the likelihood of a given outcome (raw data from environment's consistency with outcome). - Example: prior belief that heartburn and colds are common likelihood that a cold or lung disease causes coughing conclusion that cough is most likely due to a cold. **Lecture 8 -- Perception Continued** *Comparing 4 Approaches* - Unconscious inference, regularities in environment, Bayesian inference all highlight top-down processing rely on data accumulated through prior experience. - Gestalt laws of organization emphasize 'built-in' mechanisms to explain perception. - However, experience can also play a role in reinforcing the organization principles. - Experience may override innate grouping principles and vice versa. *Experience-Dependent Plasticity* - We have feature detectors in V1 tuned to respond to certain stimuli properties. - Experience-Dependent Plasticity -- more feature detectors can develop based on stimuli being more common in the environment. - Gauthier's study showed that training with 'Greeble" face-like statues created for the experiment, caused subjects' FFA to respond to those stimuli. - Some evidence that people with preexisting kinds of perceptual experiences (with cars, birds, etc.) show increased FFA responses too. - Expertise Hypothesis -- FFA may become tuned to respond to processing of any stimuli we have developed perceptual expertise with. - Explained if the average person has become an expert in faces as we are constantly trying to see if we recognize faces that we encounter. *Movement Facilitates Perception* - Movement helps us perceive things in environment more accurately than static images. - Have more data/information for our cognitive systems to process. - Example: easier to identify a horse walking in a field than one standing still, or by walking around the horse to get more visually based information to process. *Interaction of Perception and Action* - Actions involve a constant stream of updating perceptions and recognizing very subtle changes. - Example: reaching behaviour involves alternating between dorsal and ventral streams done automatically. - **Cognitive activity is dynamic and coordinated across various networks!** *Lesioning and Ablation Experiments* - An animal is trained to indicate perceptual capabilities. - A specific brain part is removed or destroyed. - Animal is retrained to determine which perceptual abilities remain. - Results reveal which parts of the brain are responsible for specific behaviours. *What and Where Pathways* - Study Tip: ventral perception (VP), dorsal action (DA), ventral temporal (VLT), dorsal parietal (Dr. Pepper). - Monkeys were trained on two different tasks learned both. - Object Discrimination Problem -- monkey learned to look for food under a certain object. - Landmark Discrimination Problem -- monkey learned to look for food next to a specific object. - Half of the monkeys were lesioned in the parietal lobe, while the other half were lesioned in the temporal lobe. - Removing temporal lobe tissue issues with object discrimination ventral stream, what pathway, perception. - Removing parietal lobe issues with landmark discrimination dorsal stream, where pathway, action. *Perception and Action Streams* - Patient DF had ventral stream damage due to a gas leak. - She couldn't match the orientation of a card to a slot while passively attempting to line it up. - Could not do orientation matching due to ventral damage. - She COULD match orientation if physically placing the card in slot action! - No damage to the dorsal stream so could do active mailing task. **Lecture 9 -- Attention** *What is Attention?* - Attention -- ability to focus on specific information or locations in our environment. - Involves prioritizing some information over others. *Forms of Attention* - Selective Attention -- attending to one thing while ignoring others. - We don't attend to a large fraction of information in the environment. - Some info. is filtered out and other info. is promoted for further processing. - Divided Attention -- paying attention to more than one thing at a time, multitasking. - Sustained Attention -- maintaining focus over long periods of time. - Gets harder as time goes on. - Example: 3-hour lecture. - Spatial Attention -- attention across space. - Example: watch out of the corner of your eye. *Modifying Broadbent's Model* - New evidence that information in an unattended channel can still reach conscious awareness. - Even when directed to ignore the unattended stream, 1/3 of participants reported noticing their name if it was embedded within it. - Participants in another study combined info. from both streams in a way that made sense to them. - Example: Dear Aunt Jane instead of Dear 7 Jane. *Triesman's Attenuation Model* - Revision of Broadbent's filter model with two components: - Attenuator -- analyzes incoming message in terms of physical characteristics, language, and meaning and then separates information into two streams. - Attended message is let through attenuator at full strength. - Unattended message let through at a weaker strength traces remain. - Dictionary Unit -- contains words, each of which have specific (experience-based) thresholds for being activated. - Common or important words have low thresholds. - Unimportant or uncommon words have high thresholds. - An unattended message producing a weak signal can reach conscious awareness if the threshold is low enough salience. - Early Selection Model -- suggests attention operates at an early stage in information flow. - So is Broadbent's filter model! *Late Selection Models* - Late Selection Models -- selection of stimuli for final processing does not occur until information has already been analyzed for meaning. - McKay's study gave subjects ambiguous sentences in attending ear. - Example: they were throwing stones at the bank. - In the unattended ear, they heard a biasing word providing context. - Example: river or money bank. - Subjects chose a provided statement closest to meaning of attended to message. - Example: they threw stones in the river, or they threw stones at the credit union. - Meaning of the biased word affected responses even though the subjects said they weren't aware of hearing them. *Load Theory of Attention* - Two major components: - Processing Capacity -- amount of information system can handle at a given moment. - Perceptual Load -- difficulty of the perceptual requirements associated with a task. - High load tasks are difficult and use lots of processing capacity, leaving LESS free resources. - Low load tasks are easy and use less processing capacity, leaving MORE free resources look for something to pay attention to. - Distractors found to have slowing effects that were diminished in high load conditions as there were less resources available to be distracted by cartoon. *Attention, Automaticity, and Competition* - Naming colours of shapes is easy, but naming colours of ink used to print words is hard. - Stroop Effect -- interference that arises from the competition between automatic processes supporting word reading and perceptual identification (colour naming). - Results in increased reaction time. - Smaller interference effects in bilinguals and trilinguals. **Lecture 10 -- Attention Continued** *Tracking Attention* - Eye Tracking -- method for measuring overt attention. - Used for research involving reading, visual search, scene viewing, etc. - Commercial and consumer applications. - Overt Attention -- attention tied to where someone is looking. - Produce data indicating where and when people looked for how long. - Good spatial and temporal resolution. - Measures a variety of things: - Saccades -- rapid eye movements. - Fixations -- short pauses on points of interest. - Fixation Duration -- how long fixation is. - Regressions -- revisiting something already fixated on. - Suggests confusion or misunderstanding. - Pupil Dilation -- provides index of autonomic activity. - Shows levels of physiological arousal. *Scanning Based on Stimulus Salience* - Attentional Capture -- salient properties of stimuli result in rapid and involuntary shifts of attention. - Salience is heavily influenced by context. - Example: a red dot stands out in a matrix of green dots, but not a multicolor dot matrix. - Bottom-up processing. *Scanning Based on Cognitive Factors* - Study measured subjects' fixations during computer simulated driving while looking for stop signs. - Subjects more likely to detect stop signs at intersections and likely to miss them when they were placed elsewhere. - Top-down expectations as subjects have learned this is where stop signs are normally based, and expectation directs search behaviour semantic regularity. - Differences in eye movements related to task instructions or goals demonstrates modulatory role for top-down processing. - Example: memorization task of a room scene has wider fixation range than visual search task for an object. *Scanning Based on Task Demands* - Task Demands -- sequence of actions involved in a task that influences the timing of when people look specific places. - Demonstrates perception-action link and provides insight into planning and decision making. - Example: eye movements to things we pick up tend to occur just prior to making the movement. *Attention Improves the Ability to Respond to a Location* - Subjects started a trial looking at a fixation point. - Pre-cueing with arrow indicated which side of screen target was likely to appear. - People tend to focus where arrow points. - Target location was consistent with arrow 80% of the time. - Task was to push button as fast as possible once target was detected. - Subjects responded faster on valid trials information processing is most efficient where attention is directed. **Lecture 11 -- Attention Continued** *Attention Improves the Ability to Respond to a Location* - Spatial Attention -- attention bound to specific locations in space. - Attentional spotlight metaphor. *Attention Improves the Ability to Respond to Objects* - Object-based attention study put a target in one of four places -- A or B on Rectangle 1, C or D on Rectangle 2. - Cue signal came where target was likely to appear. - Task was to push button as fast as possible once target was detected. - Fastest reaction times when target appeared at cued location. - Same-Object Advantage -- an enhancement effect where reaction time was fastest when the target and the cue appeared on the same rectangle, even though all 4 points were the same distance apart. *Attention Affects Physiological Responding* - Study found directing subjects to covertly direct attention to specific areas of space in visual field corresponded with maximal activation across different areas of visual cortex. - Researchers could infer where subjects chose to covertly direct their attention based on this pattern of maximal activation. *Divided Attention and Automatic Processing* - Automatization -- practice enabling people to simultaneously do two things that were each difficult at first with ease. - Occurs without intention. - May or may not involve conscious awareness. - Costs some to none of cognitive resources frees attentional resources to be allocated to other things. - Study used a task where subjects had to divide attention between remembering targets and monitoring rapidly presented stimuli. - Memory set of 1-4 target characters to search for. - Test frames of rapid presentations of letter arrays. - Subjects began task at level close to chance performance but eventually got better with practice automatization. *Cell Phones While Driving* - Risk of accident 4 times higher when using a cell phone. - Study using driving simulation found talking on cell phone (hands-free and normally) caused people to miss twice as many red lights and have longer braking reaction time.