Sensory Memory and Attention: Understanding the Interplay of Perception and Cognition - Pr, Study notes of Psychology

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Lecture 1.2 Human Information Processing
How does human memory interact with the environment? A. Human information processing is seen as interacting memory systems (page 2) 1. Can think about it a. A stimulus, through your sight and then into sensory registry, attends to the stimulus, send it to short term memory and then recall it. B. Memory Model 1. Object  Sensory Memory (raw data/large capacity)  Short-Term Memory (encoded data/limited capacity)  Long-term Memory (Complex data/large capacity) (page 2) –hot dog rocker*** a. Something that captures your attention C. Although the “standard” model is okay. A more accurate one is somewhat re- arranged (page 5) 1. Long term and short-term still interact but short-term is not as interactive ***extra credit a. Hot dog rocker ambiguous stimulus D. Sensory memory 1. “Each sense organ of the body may be said to have its memory. These memories are, in a measure, the independent of each other.” – William Burnham (1888) 2. Usually tested in vision or hearing a. Visual (sight) b. Olfactory (smell) c. Gustatory (taste) d. Auditory (hearing) e. Tactile (touch) f. Nocioeptive (pain) g. Thermal (temperature) h. Vestibular (balance) i. Proprioceptive (body position)
Why do we have SM? A. SM briefly holds information in Literal form, giving perceptual processes time to work. (page 6) 1. Snap shot of environment in front of us
Functions of SM A. Collect information to be processed B. Hold information (briefly!) during processing C. Fill in the blanks when stimulation is intermittent 1. E.g., during saccadic eye movements, SM provides a stable view of the environment a. Flip books (make it look like motion – family guy) b. Marque lights (illusion that lights are moving – on and off quickly) c. Film projectors (images very quickly) d. Clock chimes e. “What’d you say” i. auditory didn’t catch it the first time but sensory memory kicks in and replays it
Iconic (something stable in environment) Memory A. Segner (1740) is credited with initiating the study of iconic memory 1. Clinical: iconic imagery may last longer in people affected by dyslexia (Di Lollo) 2. Applied: relevance to subliminal information processing and brain washing 08/27/2013
Why might sensory memory have these temporal properties?  Adapted these cognitive systems over time o Auditory is a fleeting sense. Its only a moment in time. Not physically present in environment.  Duration of sensory memory is: o SHORT  Capacity of sensory memory is: o LARGE
Attention & Pattern Recognition  Pattern Recognition o Entails an interaction of sensory information and long-term memory, combined in short-term memory (STM)  What is this? o Hot dog rocker  You cannot recognize a sensory image as a hot dog rocker without prior memory mediating perception  We will roughly equate STM with consciousness  STM can be seen as the “cognitive workbench”  Attention: o Is the interface between memory systems o Why do we have attention?  We are constantly bombarded with information, but most of it does not enter consciousness  Attention determines what information receives further analysis…
Central Assumption:  STM is a limited capacity system. We cannot process all information at once.  We often refer to a bottleneck in information processing  Many studies have been dedicated to finding the locus of this bottleneck
William James:  “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.”
Like ^^, we can introspect about attention  You know what its like to think hard versus letting your mind wander  You know what it means when something grabs your attention o A very loud noise  You can drive and listen to the radio o Sing and listening  Dividing attention by doing two things at once o Taking notes in class  You can probably tune out, and ignore certain signals
Doing this, you can probably come up with a reasonable definition  “A pool of mental effort that is selective, shiftable, and divisible.” o What you want to listen to o What you are doing, listening to o Dividing a certain amount of attention to different things  Fair enough, but this is a science, and as scientists, we’re going to study attention a bit more carefully…
Selective attention for auditory signals o Attention selects a subset of information in SM to pass on to STM
***Crossing the Threshold  something that has a personal connection o Some items have a very low threshold o Others have a higher threshold  Which one has a higher hurdle?  Fire or water  Water  Your name or significant other  Significant other  Significant other or table  table
A problem for Early Selection:  MacKay (1973): o The unattended message influenced participants’ later decisions about the meaning of the ambiguous word (bank)  They were consistent with the unattended words  River, water, creekriver bank  Coins, dollars financial institute
Deutsch & Deutsch (1963)  Proposed a late- selection model to remedy early selection models. o INFOSM Detection STM  All info is Getting through  STM is where you make the cutoff of info you will attend to and not  All stimuli pass the detection device. Selection for further processing occurs in STM.
Commonalities  All three theories portray attention as a system that selects one signal from its competitors  The theories are supported by phenomena like the cocktail arty effect 08/27/2013 0 Attention & Perception Cont. (1.4) 

Early selection models of attention:  (page 1) o B : SM selection devise(filter) then onto detector and into STM o T: can ramp up your attention at the expense of the attenuator picking up on other things
Late selection model of attention:  (page 2) o Recall that evidence for late selection came from Mackay (1973)  Messages from the unattended ear bias participants’ later decisions about the meaning of ambiguous words in the attended ear. o And…
The Stroop Effect (page 3: data)  Go from reading the word out loud o Saying color out loud of ambiguous objects o Saying the color of the word not the word itself  Reading words is a natural process o When you have to divide your attention by ignoring the words and just pay attention to what the colors are  Experiment o Part 1: Please read the following words aloud, as quickly as possible…
Kanhneman’s capacity theory  Developed in response to failures of selective attention (blue/green/red)  Spelke, Hirst, & Neisser (1976) o Ss listened to messages and typed them.  Easy enough… o At the same time, they read a book aloud.  WTF??
Selke et al.’s (1976) findings:  After 6 weeks, people could perform both task almost perfectly!
Shiffrin & Schneider (1977)  Ss completed two simultaneous tasks: o Holding information about target stimuli in memory o Paying attention to series of “distracter” stimuli, waiting for one of the targets to appear
The tasks included two conditions  Consistent Mapping (CM) o Targets and distracters came from different categories (letters versus numbers)  Varied Mapping (VM) o Targets and distracters came from the same categories (letters and numbers) o Targets in some trials were distracters in others
Results: Consistent Mapping  At trial 1 – 55% correct  By trial 900 – 90% correct o Even when the time frame was only 80 ms  Across trials, only time frame affected performance o Ss learned to search all of the frames in parallel, without a cost of increasing complexity  What do there results implicate? o Automatic Processing
Results: Varied Mapping  Everything affected performance  Ss detected targets poorly, especially when the memory set or frame size were large.  Ss only achieved 90% accuracy with a 400ms time frame (and lots of practice o Ss had to search all of the frames in serial, with large processing costs with increasing complexity  What do these results implicate? o Controlled Processing
Shiffrin & Schneider (1977)  Automaticity can develop in VM, but it takes people 3000+ trials CM performance 
Is automaticity always learned? Does it ever occur naturally?  Work by Treisman and colleagues suggests that some automatic processes are “built-in” to the human brain…  “Pop-Out effects” in visual search
Feature Search  Unique targets are detected quickly  RTs not affected by # of distractor items  “Yes” and “no” responses equally fast  Indicates parallel search o Unique features seem to “pop out” of the display
Conjunction Search  Conjunctions of features are detected slowly  RTs increase with # of distracter items  “No” responses are slower than “yes” responses (2:1 ratio)  Indicates serial search
Feature vs. Conjunctions  Unique targets: are detected quickly o RTs are not affected by display size o Y/N equally fast  Conjunctions: of features are detected slowly o RTs increase with display size o ***N slower than Y
Why do pop-out effects  Treisman’s feature integration theory o Basic features of objects (e.g., color, shape, angle, motion) are detected automatically o Features must then be combined into objects  Your brain combines and interoperates form the environment  Object  Pre-attentive Stage (analyze features)  Focused Attention (combine features)  Perception
Feature Integration Theory (FIT)  Basic Experimental Method  Hubel & Wiesel (1957): Feature-detectors in cats o Electrodes recorded from single neurons in the occipital cortex o Results  Feature detectors  Different neurons in visual cortex respond only to specific features:  Shape  Angles  Movement  Contrasts  Etc.  They also found combination detectors  Not only do these experiments also work on monkeys…  But they reveal even more complex detectors  Features detectors need early input in order to develop...
Blakemore & Cooper (1970)  Sensory restriction: kittens raised without exposure to horizontal lines were later blind to them
Lettvin et al. (1959): ***“What the frog’s eye tells the frog’s brain”  Have different species evolved different feature detectors?  Frogs have… o Edge detectors o Contrast detectors o Movement detectors o “shadow” detectors o Convex edge detectors
Feature Blindness  Riggs et al. (1953) o What if eye movements weren’t possible? o Using a head-mounted projector, Ss saw images coming from their own eye  Riggs and friends expected people to slowly go blind to the picture  It turned out to be much cooler than that… o Results: Features slowly come and go—then it’s gone
There are problems with purely bottom-up theories of perception  The sheer volume of information processing may be impossible… o Consider reading:  Most words have 5 letters and most letters have 5 basic features  Typical reading is about 250 words per minute, which would be 100 features per second o Scanning a crowded room could require millions of features per second  It combines bottom-up and top-down information o Bottom-up: sensations/feature detection o Top-down: knowledge / expectations  We use background knowledge to optimize our perceptual processing
These are Contest Effects in perception  -Context Effects- provides evidence for top-down perception o Context can be used to help interpret distorted or ambiguous bottom-up information o This has both positive and negative effects…  EX: Many other examples of perceptual biases exist…
Bottom-up and Top-down info. can combine in weird ways…  With these images upside down (reducing top-down knowledge), they look okay…  With the images properly oriented (increasing T-D), the second Madonna looks more grotesque than the first  Are “perceptual objects” always sent to the conscious mind? o Contra-laterally  Right does left  Left does right
Weiskrantz tested a patient named DB.  DB had surgery to relieve (very bad) headaches, which left him blind in part of his left visual field.  DB’s blind area, But what are the numbers o The accuracy of his guesses  Coined the name blindsight to describe DB’s condition o A totally “blind” woman who can walk an obstacle course, catch tennis ball, avoid traffic… o Monkeys with NO visual cortex, who still manage to dodge flying objects
2 Separate Systems  Perception  Consciousness o Effected by the objects  S.P. has had a long and controversial history o For instance, the famous “Eat popcorn – Drink Coke” experiment by Vicary was a hoax  Take a movie, cut it and put an image, than have the movie continue
Within limits, subliminal perception must happen: It’s logical necessity…  Remember the cocktail party effect?  Subliminal advertising, however  Greenwald et al. (1991) 1 of 2 essay questions o Describe what they did, trying to learn, and hat they found, then asked to expand  Used flyers to find participants to test subliminal messages to effect a persons behavior  Long term behavioral effects  Twp manufactures of self-help tapes  Self-esteem  Improving memory (mnemonics)  Took the labels off and wanted to give tapes the best chance of succeeding o Found people who wanted or needed these effects  Participants were motivated and wanted this to work  Let tapes go home without labels  Subliminal Tape contents (there is no effect of subliminal content) o Memory and memory label o Self-esteem and self-esteem label o Memory and self-esteem label o Self-esteem and memory label  Had to complete different tests in order to measure where they were in memory and self-esteem
A parade of freaks…  Or, interesting disorders following brain damage o Visual Neglect***  Usually caused by damage to the right parietal lobe  Involved in bringing together sensations and perceptions  Patients will “neglect” the contra lateral hemi space  Divide the visual field and would neglect the left side of the space  They will occasionally neglect (deny) the contra lateral side of their body!
Some Examples  Line Bisection TASK o Normal  Get the center of the line o Patient  Would put the center being to the right of center  Experimenter’s model o Patient will neglect half of the painting  Self-portraits by an artist with left-side neglect
Do neglect patients ever process anything in their blind field?  Semantic Priming o Something that is brought to mind due to the primed meaning
Other interesting disorders  Prosopagnosia: An inability to recognize faces. All other objects are okay o Usually caused by damage to the fuisiform gyrus o Despite recognition failure, GSR changes when familiar faces are presented…
Opposite Syndrome..