Eyewitness Memory Article

Eye-Witness memory article:

·      Major possible influences on the eye witness memory?

o   Whether or not they talked to others

§  People CONFORMING to other people: Can forget info, mis-remember, are influenced by others.

§  UNCERTAINTY : informational influences (questioning their own feelings or memories)

§  FALSE MEMORIES: incorporating the other’s view into your own memory.

·      Timothy Mcveigh’s case is a good example. He probably didn’t have an accomplice, but the two other eye-witnesses conformed to the other’s opinion.

·      Another example is Barry George: Only 1/16 witnesses identified him, but the person talked to others in the cab, and not they are 95% sure.

·      1. Normative influence: weighing the social cost of disagreeing, you want to conform to the norm.

·      2. Informational influence – being uncertain of your own memory up against someone else’s.

·      3. Memory distortion: you now think that this is what happened – it becomes part of your episodic memory.

·      What determines the magnitude of a normative influence?

o   Weighing the social cost of agreeing or disagreeing.

·      People talk or conform, and then they are interviewed separately. Do they still agree with the social norms?

o   Yes, maybe they want to appear consistent.

o   Maybe they trust in the other person’s opinion based on their confidence, their expertise, if they are in the majority, or how important the issue is.

§  An example is listening to school children vs. listening to police officers.

·      Source monitoring errors – you’ve forgotten the source of your memory – lost representation of the source from the representation of the memory itself (confuse what they actually saw with what someone else told them).

·      There are three different processes:

o   Conform

o   Unsure

o   Create a new memory

·      Big point: memory, then, does have a social component.

Stereotype Threat Article, Adaptive Memory Article

Stereotype Threat Article:

·      Academic settings – presume the incompetence of several groups “threat in the air”

·      Stereotype threat: your social environment is threatening to stereotype you, not treat you as an individual

·      So, stereotype threat decreases good performance. How?

o   It limits working memory capacity because you are thinking about your bad environment, and you’re self conscious about your performance. Which takes away from your performance of complex cognitive tasks. (It gives you a cognitive load).

o   They want to make sure they aren’t confirming the stereotype, and it eats up resources.

o   Ex. Women vs. men in math – women did much worse when told the task would measure gnder differences.

·      Who is most susceptible to stereotype threat?

o   Those we are most invested in doing well in that domain (ex. Academics) –those who were the most achievement oriented were effected more.

·      Error-related negativity – reaction to an error.

o   The stereotyped who cared the most had higher error readings – it all ironic. It makes them more sensitive to their own errors.

·      How does stereotype threat effect our response to our own anxiety?

o   Sensing our own anxiety is a signal to us, and it plays a part in making us more nervous.

·      Under what conditions does anxiety reduce our working memory?

o   When we’re not confident or are doubtful – anxiety and doubt become a distraction.

o   (For everyone, not just for a certain group)

·      Do people try to not think anxious thoughts?

o   They try, but it doesn’t help. In fact, it makes it worse. Though suppression means you’re constantly monitoring so that takes cognitive resources too!

o   A vicious cycle – impair performance more and more.

·      By reappraising your emotions, you can break the cycle, an see your anxiety as a helper.

·      Measured sympathetic nervous system activation – is that a bad thing?

o   Yes, for women who though of the anxiety in a negative light, they couldn’t reappraise their emotions. So, anxiety is not always bad for performance …. Unless you think it is!

Adaptive Memory Article:

·      Maybe coming from a functionalists perspective?

·      Proximate mechanisms: Psychological processes that we think explain how something works. A chain of events that leads to an outcome we measure, as opposed to evolutionary changes.

·      In their study, the 95% confidence interval didn’t overlap – strong results showing that survival words are recalled better.

·      The author is more interested I how these mechanisms worked a long time ago and how were they adaptive?

·      What makes memory strong? Some factors that make things memorable are:

o   Forming an image

o   Processing for meaning

o   (both of these are proximate mechanisms that make memories strong).

·      So why do they work? Largely an unaddressed question.

·      What three suggestions does the author have about why we have the memories that we have? i.e. that respond to images, etc.

o   Not just so we can remember things from the past, but instead to help us in the present – learning from things that have happened to us and for the future too.

o   Memories are domain-specific – they are designed to help us remember useful things that help us. (maybe also working memory is around to help us forget trivial things. So, we wonder, to what extent is our memory due to future ideas?)

o   Memory also helps  us survive and produce offspring.

·      Table one from this article shows that we should be able to remember where what is, etc, what food is good, what isn’t, what prey looks like…

o   If  you couldn’t remember these things (like navigation) you would be at a disadvantage to survive.

·      The author thinks a functional perspective on memory is important.

·      What evidence supports the survival-relatedness with memory?

Memory wiki:

·      2-major theories about why we forget:

o   Trace-decay theory – the memory itself deteriorates, so it doesn’t maintain is form and we can’t retrieve it.

o   A major explanation is Interference. There are two types:

§  Proactive interference: things you learn now are hard to learn because of old memories, they disrupt. Or it can work the opposite way:

§  Retroactive interference: new memories disrupt the old ones

·      What is the pattern of forgetting over time?

o   Its very rapid at first, and hen slowly after that (like  a power log)

Survival article continued:

·      Survival processing enhances retention – we are more likely to remember things we are likely to need again, and we are less likely to remember things we won’t need again.

o   Its like our mind is adapted to know things about our surroundings.

·      Other major claims:

o   Does thinking about how items of information may be related to survival effect how easy it will be to remember them?

§  They did three tasks, survival words, moving words, and pleasantness. (They were rating these words)

§  In the end, the experimenters gave them a surprise recall test, and survival related condition of words did indeed have more words remembered. Significantly!

o   It remains against other conditions too that don’t have anything to do with fitness , like taking a vacation.

o   Levels of processing phenomena: thinking about the meaning of a word makes it more likely to remember than words about something like color.

o   Thinking about– does this word apply to me? – self reference are very well remembered – relevance to the self may have a special stance.

§  Is this just deep processing of the words in this article?

·      No, a graph shows that surviving is still better remembered than self-reference, generating the words, intentional, pleasantness, imagery – survival is better than all on recall.

·      Why does thinking about survival make so much difference?

o   Its an important research for the future.

o   Survival is very elaborate encoding

o   That kind of thinking (survival brings out strong emotions)

o   There may be survival module?

Magical Mystery of Four and lab notes

Magical Mystery Four: How is working memory capacity limited, and why? (Cowan)

·      George Miller says 7ish chunks, but Cowan says 3-5

·      Chunking: grouping smaller items into larger ones. Perhaps chunking in different ways effects the number of items you can get.

·      So, whats the significance or working memory for cognition?

o   We are relying on it whenever. We are thinking about something/processing it (like the beginning of a sentence should be remembered by the end of it).

o   Working memory may vary and be predictive of cognitive ability

·      What are the ways in which people hold things in working memory?

o   Remembering their voice, mentally, see the situation, running span procedure (don’t know where the end is going to be)

o   Its hard to answer because there are a variety of ways to remember things.

·      Distinguishing  between processing-related and storage-specific measures of wm capacity??

o   Raw info holding capacity- how much is there? Without rehearsing etc. no tricks – this is storage-specific.

·      Cowan regards storage-specific as more important because it’s the core of how the memory processes work, not a contaminated measure by tricks. Etc.

·      How can one ensure storage-specific measurement of capacity? We have to stop other various kinds of processing.

o   Brief simultaneous spatial array

o   Attention taking place after the sound has ended (dichotic listening – report unattended channel.

o   Overt repetitive saying of one word – “the the the the” while trying to remember something

o   Series with unpredictable ending – running span.

·      Why may this be more relevant/important for working memory?

o   Practical implications, maybe sometimes we don’t have time to use those tricks – much of the times, we can’t use tricks so we need to see what the most basic memory is.

·      Cowan sees working memory as needing to be tested without tricks or contaminants.

·      Central memory (working memory) is important because it underlies problem solving and abstract thoughts

·      HE thinks there are developmental trends in memory – it changes across the lifespan, and may predict intelligence. So, it is fundamental to figure out how to measure it.

·      What is the significance of the working memory storage? Is it a strength or a weakness?

o   How can it be a strength?

§  It is a strength in that we don’t have to be overwhelmed with to much info because we can’t store that.

§  Short lists can be organized effectively.

§  An average of 3.5  items seemed to work best

§  Simple means we can manipulate info better

o   How is it a weakness?

§  No more brain tissue to assign to this task, etc.

Lab Notes:

·      Degrees of Freedom – 2-values (f(df1,df2)=____P

·      The difference between _____  and __________ was significant (paired + (df) = ______, p=_______)

·      The standard error of the mean =SD/sqrt(n)

·      Larger sample size = smaller standard error

·      Bonferroni tests: dividing the p-value by the number of tests. A general strategy to control experiment wise error. (how likely that they’re producing false alarms)

·      A 2-way interaction is different at different levels of the 3^rd variable

·      There are special tests you can use if you don’t have normal data

o   1-way repeated measures (Friedman)

o   between subjects (Kruskal)

·      The one difficulty of t-tests after ANOVAS is that you can’t control the error overall.

Memory from Wikibook and Lab notes

Wikibook: Memory

·      Types: sensory, short-term (working memory), long term memory.

o   All of these three are the interface between perception and memory systems.

·      Sensory memory:

o   Iconic memory (visual input): lasts for less than 1 sec

o   Echoic memory (auditory input): less than 5 seconds

§  When someone is talking to you while you’re talking to someone else, and you still know what they’re saying/

·      What allows the transfer of these types of things to become a more durable memory?

o   Attention determines this (ex. Shadow task – attending to one stimuli in the right ear, but not attending to the left: you loose everything from the left. *This is an example of high perceptual load).

·      If you have an easy task (low perception load), late selection may come into play – effected by high cognitive load, that is, if you have a lot of stuff in working memory.

·      Main characteristics of short-term memory:

o   A link between sensory memory and long term memory

o   It can handle 5-9 pieces of info (chunks) or maybe 3-5. (George Miller and the magical number 7 _+or- 2).

o   Chunking- process of bundling information.

o   Info is held for 15-30 seconds, measured by giving the person a distracter task at the same time

·      How are they maintained?  In working memory?

o   By voluntary attention (maybe working memory and attention are closely linked).

·      Where did working memory come from?

o   Baddley said that working memory’s purpose is not to hold info, but to work with or manipulate the information. To carry out a task.

o   Use of information to achieve a goal you have.

o   Wm can process different kinds of information simultaneously, so wm is not just one thing

§  Visually-based and auditory based and space based.

·      What lead to the concept of working memory?

o   The will to do something with information

o   Process different types of information simultaneously

·      Different components of working memory:

o   Phonological loop (sound based)

o   Central executive (manager)

o   Visual spatial sketch pad (visual-based)

·      Its not the working memory can store info over time, but it can support other cognitive processes, while we do other things.

·      The old model of memory is that memories come to senses, to working memory, and then to long term memory. But now, some people have impairments of working memory but not long term memory. So, maybe we don’t have to go through working memory to store a memory…

·      Long term memory, main forms:

o   Declarative memory (explicit)

§  We can consciously recall – awareness of having experienced these things.

§  2 types

·      semantic (can know things without having experienced it directly such as early childhood memories or other lands, etc)

·      episodic (specific episodes in your life – personal sense of self).

o   Implicit memory:

§  No conscious awareness (our behaviors may still be changed without our awareness, so the info is stored somewhere

§  2 kinds:

·      procedural (knowing how to do actions etc. maybe unconscious. Involves motor control areas or more mental procedures. More associated with doing).

·      Perceptual priming (ex. Fragment completion – may also be unconscious… we were recently exposed so we are more likely to).

Lab notes _

·      Our experiment was a within subjects design. IV with 3 levels (congruent, incongruent, and baseline).

·      We found the median and response times for each condition for each person.

o   We used medians because some people got distracted one time or were really fast one time, and that significantly effected the data.

·      We checked to make sure that our data was normal to run tests.

·      Main effect: the effects of one IV averaged across the levels of the other IV

·      Interaction effects: are the lines parallel or not?

·      Between subjects: are the lines close?

·      Within subjects: is it inclining/declining from L to R?

·      dual taks: we have 2 IV that re both within subjects. (box size and speed)

Attention Articles Continued

Attentional Limitations in Doing Two Tasks at Once:

• Why is multitasking becoming more important?
• Computers, etc. our life is much more quick than it used to be, and there are lots of things trying to grab our attention.
• People think they can multitask, but most really can't. This is another example of a failure of meta cognition.
• Central Bottleneck: central processing that can only handle so much info and limits your attention.
• This article may suggest that you just get better at the task so you don't have to give as much attention to it.
• Working memory (also like a bottleneck) - maybe it is closely related to attention... that is, how much can we keep in our working memory?
• Maybe there is hope for multitasking if we can modify the task to be easier as well as train people for the tasks.
• Perhaps this is a biological issue - otherwise we wouldn't be able to function if we attended to everything around us.
• To measure, you could use accuracy or response time. The authors of this article argue for response time.
• Response time is good because your speed in doing something may be more effected than your accuracy.
• P.R.P - Psychological Refractory Period : This is when the Reaction Time 2 is longer with the short time between stimuli (SOA). In other words, central processing gets delayed because it is still working on the first task.
• Stimulus Onset Asynchrony (SOA) - Time between two tasks.
• So maybe we are never truly doing two things at once, maybe we are just good at figuring out when to split/shift the focus of our central processing.
• If there is a long enough delay, perhaps the bottleneck is avoided (with a long time between the two tasks, a long SOA).
• ex. cars on a one way bridge - a jam is not noticeable with more time/space between each car.
• So, what other tests can show the presence of a central bottleneck?
• A longer reaction time for task 1 should correlate with a longer reaction time for task 2. (trial by trial).
• If these things happened in parallel, then we could sometimes finish the 2nd one first, but since that never happens, it may be that there is a bottleneck.
• They suggest a strategy of making Task 2 easier/shorter, to see if it could be completed before Task 1.
• If you make task 1 easy, it is hard to demonstrate that no central processing is needed for task 1. You wouldn't have a very straightforward interpretation of the data.
• If you make the 2nd task easy, on the other hand, it shouldn't require a psychological refractory period if it doesn't need central processing.
• latent bottleneck: response time 1 is so short that it may finish before a 2nd task even begins.
• If you eliminate PRP, perhaps there is no bottleneck..?
• If you make task 2 very easy, you could make it so central processing for task 1 wasn't necessary, but you might use it anyway, and task 1 would hog it from task 2.
• 3 Strategies where passing the bottleneck might have worked:
• ideomotor compatibility: stimulus resembles sensory feedback from the response (ex. saying a word as it appears on the screen).
• practice: may help, but these studies were measuring accuracy, not reaction time. They may still have a delay in processing. But there are also cases where practice seems to have eliminated PRP totally.
• Special Response Systems: tings like eye movements may not require any central processing, so there may not be a bottleneck.
• A response where the person doesn't have tot hink about at all may be the key for eliminating bottlenecks. 
• In all cases, eliminations that worked were when the easy task is task 2, not task 1. 
• Implications: processing is non-recurring, so you may encounter things that are very new and you can't practice them, so probably things like cellphones and riving will never really go hand in hand.
• So, how far can multitasking go?
• not very far, most studies have shown bottlenecks. It is unlikely we can sidestep bottlenecks all together.

Neural Basis of Selective Attention:

• Contextual modulation: the neurons that are responsible for our visual perception are active in a different way when we're attending to something than when we are not (i.e. occipital lobe for vision).
• The reaction of the occipital lobe is modulated (changed) in different contexts. It is more active when you are attending to a stimuli.
• There are parts of the brain that modulate, and there are parts of the brain that focus attention for those parts.
• some stimuli may not be represented in the brain if they are not being attended to (this may disagree with the other articles...)
• Bottom-up attention: Stimulus driven; salience (most noticeable or important) External
• Top-down attention: voluntary; intentions or goals (this is more where the article focuses). Internal
• Toward what can attention be directed?
• Visual space : spatially focused attention modulates neural activity in the extra striate cortex.
• motion-based attention : area MT (for motion) is activated bt motion. attention can indeed be motion selective.
• Object-based attention: different areas that are specific to objects are activated during different attending. (such as the face area or the house area during the face/house exercise).
• What areas of the brain produce signals to attend or not?
• Frontal eye field: may be linked to planning to move your eyes somewhere. (FEF)
• Superior Parietal lobe
• intraparietal sulcus
• Topographic maps: areas of space correspond to areas in the brain.
• Is the attentional area also topographically organized? We don't know yet.

Attentional Blink

• What is the attentional blink and under what conditions does it occur?
• when a person is doing two tasks, you catch the first one very well, but the second task you fail at. It usually takes about .5 seconds to recover. (but not when the stimuli are back to back, just when they have some space between them.)
• The classic explanation of this phenomena is that there is a resource drainage going on (that is, we have a limited capacity to process information). The authors of this article disagree.
• The author here says there is actually a temporary enhancement.
• They claim that it is only when you have distractors in-between the stimuli that you have an attentional blink.
• The author says the blink may just be because the other experiments are being done with distractors in-between.
• this leads to reactive suppression - that is, exposure to one kind of thing takes away from elsewhere. Without distractors, there is no blink, and that is exactly what they found.
• The tasks done in labs are kind of unusual, so it may not apply to something like driving in the real world. He says that it is a useful mechanism though, because it helps focus your attention on one thing.

Emotional attention:

• perception may lead to emotion, but emotion may also effect what we perceive.
• Perhaps this means emotion interacts with attention networks or mechanisms. In fact, maybe they interact in the same way, or maybe they are the same system?
• Emotions may be able to enhance some perception or diminish others.
• We respond faster to emotional stimuli (negative ones, such as snakes), but positive emotions may also have an enhancing effect.
• Positive stimuli tend to broaden our attention, where as negative stimuli helps us narrow our attention to the one thing.
• Is attention enhancing certain areas of the brain?
• Emotions act a bit like attention - yes. If a face has a strong emotion on it, such as anger, the Fusiform Face Area is activated more. So yes, emotions do act like attention on the neural level of stimulation.
• So, are they really the some thing? Do emotion and attention act through the same systems as other stimuli?
• This can be answered with an example of someone with neglect syndrome. Would they respond to emotional stimuli in the neglected area?
• They do indeed attended to emotional things in that hemisphere, so the emotional attention is not exactly the same thing as attention. They operate partially independently, but they do seem to interact.

Attention, Distraction, and Cognitive Control Under Load:

• The fundamental question: Does attention act to enhance the perception of some stimuli at the expense of other stimuli? Or are all stimuli that reach our system always perceived, whether or not they are attended to?
• Its hard to know which is right. Attention may be a process of filtering out irrelevant information (early selection), or maybe the stimuli are processed completely, but are sorter through mentally later (late selection).
• This article argues that both early and late selection work together under different circumstances.
• Summary of main ideas:
• high perceptual load: demanding perceptual task: we may be so engrossed with a current task that other stimuli truly aren't processed.
• high cognitive load: here, distractors may be perceived, so when/how much of an effect do they have? Your reflexive processes are here (distractors). They may have greater interference in high cognitive load tasks.
• more competitive under a low load, as well as in attentional capture ex. judging line lengths is high load, so you are less likely to process the distractor.
• We do less well in attentional tasks when we have a heavy distractors load.
• higher perceptual load helps, (better at early selection), but high cognitive load decreases (worse at late selection. They are opposites).
• distractors may effect brain processing.
• inattentional bias.

Change Blindness, Lab notes

Change Blindness:

• What is change blindness?
• where people can't detect exactly what is changing (in a picture or in real life, etc).
• When they don't see the signal change happening, its hard for them to detect it.
• 1950 began the study of change blindness, but now the studies are more ecologically valid (they have implications for real life).
• What is a socode?
• A category of eye movements
• the period when your eyes are moving from one scene to another - rapid darting movements where your mind has to complete the idea.
• Socodic Suppression: during socode, visual perception may be shut off or maybe it blurs so we can't see what's happening. This may be when we have change blindness.
• Flicker Test: first there is a picture, then a blank screen, then another picture. It flickers back and forth until the person can detect the change. 
• What are the conditions where we seem to fail to detect change?
• if you mess up the signal in the change
• if there are other elements for visual signals that distract from the change
• if a change occurs very gradually
• if you aren't expecting a change in that moment
• Major previous findings:
• attention is diverted which is change blindness.
• change blindness is less likely if the change is closely tied to the meaning of the scene.
• It may be necessary for you to have attention to the stimuli to be able to detect the change but...
• attention may not be sufficient for you to detect the change. Detecting it requires them to encode the information before and after the change, and then to be able to compare the two.
• What is it that will guarantee attention? What will make us attend to the change?
• we aren't really sure, but there may be two things:
• visual distinctiveness (external): things in the scene that grab out attention.
• expectations (internal): if you expect a change.
• Do experts do better at change blindness?
• yes, especially for semantically meaningful stimuli, but perhaps experts would be worse in things they aren't experts in? We don't know.
• Does change blindness mean that there is very little info represented in our minds?
• not necessarily, just that we need to represent the scene before and the scene after to compare them.
• maybe we have representations, but we don't think to compare them (ex. man reading map and person being switched in between)
• In addition, observers sucessfully recognize an object, even if they don't notice the change. They attended to it without locating the change.
• Can you detect changes and not know it?
• Mindsight- sensing a change without actually seeing it.
• But we aren't quite sure if this is right.
• Change blindness blindness: we think we are better at detecting changes than we are... this is a failure of metacognition.
• implications : driving while talking on a cell phone, etc. Activities where we have little conscious awareness.

Lab Notes:

• Interaction effects: when one variable differs at different levels of the other variable (ex. the effects of dosage is different for males or females, that is, the dosage effects males and females differently at different levels).
• main effects: overall influence of an I.V.
• effects of one IV averaged across the levels of the others.
• ANOVA - really is trying to break up the variable into pieces and analyzing the pieces.
• doing this assumes that the variances of each condition is about the same.
• Can check this with something like a boxplot display
• for our data, we have a strong p-value, but our variance for each condition may not be equal. 
• Ceiling or floor effects: a restraint on the upper limit (ceiling) or lower limit (floor) that the value of a dependent variable can take.
• Besides just a within subjects or just a between subjects approach, you can also have a mixed design.
• For example, depressed people at 3 different times (within subjects variable) in 2 different treatment groups (between subjects variable).
• This example is a 3x2 mixed design

Sensation and Perception / Signals

Sensation and Perception Book

• Do our sensations/senses convey reality?
• most of the time,  but what about tricks or illusions?
• ex. matching lines, constantly descending tones
• So, we cant always sense exactly what's going on.
• Strictly speaking, we'll have to go with no, our perceptions do not always convey reality. 
• People often contrive physical and psychological responses to stimuli (i.e. optical illusions (or visual illusions may be more appropriate.
• But our senses serve us very well, they don't often mislead us
• there should be an important distinction between the physics and psychological of a stimuli.
• What evidence is there that perception is not just physical? 
• Perception involves cognition and psychological context (ex. of 13 or a B? And old lady or a young woman?)
• top -down perception - things from "high" in our mind that influence our context, as well as things that come from "low" in our minds (like our perceptions).

ANOVA clip:

• maybe the parthenon was built to trick the eye into thinking it was perfect. They compensated for our natural visual distortion to make it more perceptually perfect.
• Gestalt Psychology- principles that organized perceptual wholes.
• law of proximity
• law of similarity
• law of closure
• continuation
• common fate
• Helmholtz: "Contructivists theory" - we add information to what is provided in the stimulus to draw inferences with our conscious knowledge. "unconscious inferences" - way of processing sensory information.
• Bev Dottle's art is a good example (with the horses and mountains, etc). 
• Phiphenomena: 2 red dots flashing - we tend to see movement, even though there is none. This is an example of our perception tricking us.
• Method of limits
• methods of constant stimuli
• methods of adjustment
• discrimination threshold
• all of these were difficult to measure when the people might be bias or participants may be dishonest, so, they came up with measures of biases:
• forced choice methods: not so much a yes or no answer, but when or where? - This way there would not be people saying yes 50% of the time (Percentage correct against the percentages of chance)
• signal detection theory: separate participants sensitivity to the signal vs. biases of the patient. This method takes into account the role of decision making in these experiments.
• There were a series of trials were a stimuli either occurs or doesn't occur (and the task should be challenging) and then the person says yes or no.
• How might expectations effect the decision to say yes or no?
• you may try really hard to see something... maybe you'd have a bias or motivation to say yes.
• context of previous experiments may matter too, or social contexts.
• Signal detection theory can detect these biases and separate out our sensitivity to the stimulus from the bias. (4 categories, hit, miss, false alarm, correct rejection).
• There is always ambiguity in the experiments with backgrounds or other stimuli occurring at the same time, random firing neurons, etc.
• Stimuli is a signal to be tested against a background of noise.
• when hits = false alarms, then there is no ability to detect really anything.
• ex. distribution of effects inside the brain. When the distributions sit on top of each other, you aren't really detecting anything.
• d prime - measure of sensitivity; ability to detect.
• criterion - shows bias (yes more or no more). If you say yes more, your signal detection goes up, but so does your false alarms  (low criterion)
• Receiver operating characteristics: plots hits vs. false alarms. If hits = false alarms, the line will be perfectly diagonal. So, the more sensitive you are, the more the curve will be bent up to the left. 

Signal Detection Analysis

• You can't just look at hits of just look at misses, because you get 100% if you say yes all the time, but also 100% on false alarms.
• d prime - differences between distributions of hits and signal absent (sensitivity to signal). 
• A smaller d prime is harder to differentiate
• percentages correlate with the ares of each
• The more separate the two distributions of false alarms and hits are, the more curved away the ROC will be, the greater the d prime is, and vise versa.
• The degree of bend in the ROC is an indication of our sensitivity to the signal.
• ROC should be generated from multiple points from the same person.
• "noise" is background ongoing elements.
• how far apart the two distributions are depends on the actual strength of the signal and our sensitivity to it (d prime).
• You have to take into account the cognitive business that interferes with the actual sensory perception.
• This helps us get the bias out of motivation or setting or expectations.
• SDT separates what the person can truly detect and what is just biases.
• ex. a radiologist in detecting cancer
• This method casts objective light on performance.
• Its a lot like statistical tests with Type 1 (false alarms) vs. Type II errors (misses)