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NATS 1860 Note 18.docx

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Natural Science
NATS 1860
Keith Schneider

NATS 1860 Note 18 Why does a cognitive system need a memory? Learning - Inference o You need to have prior knowledge in o - Integration o Scene preparation  Since you don’t see everything at the same time you have to store time and space information o Sentence processing  In some languages this is necessary - Recognition o It is important to know friend from foe, and recognizing problematic people - Problem solving (mental arithmetic) o You add things into your memory and then retrieve them again through short term memory Questions to ask about memory? - How long does it take to retrieve accessible memory? o How long do things stay in your memory? - When will memory eventually be forgotten and inaccessible - Capacity limits on stores? o Is there a differentiation between long and short term memory Types of memory processes - Encoding = putting items into memory - Maintenance = keeping the memory alive and active - Retrieval = finding the encoded information and retrieving it - These three processes are what are referred to during the memory process. Simple Model of Memory - You start out with the sensory information storage  all the information coming in (visual, auditory, etc.), each of the sensory systems has a “buffer” that can store an enormous amount of items for a limited amount of time. - Once you get through the information storage, some of it is transferred to different aspects of your memory  some of it is going to be processed, and the rest will be forgotten  this has to do with attention - Attention governs what gets into the short-term memory. You can keep things in short-term memory by repeating it over and over to keep it in their. - Consolidation is a method through which something is automatically stored in long-term memory from short-term memory o If you get knocked out, all of your short-term memory disappears o Short term memory is stored through electrical information floating in your head. o Long-term memory is stored by protein and protein synthesis. Types of memory stores - Sensory information store (SIS) o Large capacity, brief, contains sensory features like a buffer - Short-term memory (STM) o Limited capacity and duration contains identified features - Long-term memory (LTM) o Nearly unlimited capacity indefinite duration varied content Sensory Memory - Capacity to retain sensory information for a few hundred milliseconds after presentation - If this information isn’t used it is discarded - Attention is a scanning process sphere in which it is easier for you to remember things that you specifically pay attention to - You can store about 4-5 items o You lose it quickly - There is a partial report which you can see about 3-4 items - All digits are retained for some time after the presentation - You can read out any line from the buffer, however not all of the lines in the buffer Properties of Sensory Memory - There is a fast decay of time (3s for iconic memory) - It is modality-specific - It is overwritten by new incoming information Arguments for two memory stores: - Some things can be remembered for a long time, others can only be remembered for a short time - Short-term functions can be interrupted while long-term functions remain intact - Primacy and recency data in free recall experiments - Serial position curve: in free recall there is a list of words that is presented to be memorized. Primacy Effect: - In free recall of a list is presented to be memorized - Words presented at the start of the list are more likely to be remembered than those in the middle of the list - Due to earlier words being stored processed to greater extent and stored in longer term memory Recency Effect: - Words presented at the end of the list are more likely to be remembered than those presented in the middle Differentially affecting primacy and recency effects - Can perform manipulations that affect one or the other - Evidence for distinct memory stores - Long-term memory affected by representation rate and number of presentations - Short-term memory affected by interference and delay Short-Term store - There is limited capacity and life time (there is a few seconds) - It can be maintained through rehearsal by repeating to self, requires effort, susceptible to interruption, and you’re generating imagery into memory - Can be committed to long-term memory Capacity of Short Term Memory - Seven plus or minus two units regardless of the type of data (George Miller) o There are 7 digits in the phone numbers because that’s what people can memorize on average - There is actually four digits – o Chunking is when you code single units into larger words (thus, it enlarges our capacity - Chunking depends on LTM activation in which you have single units moved to larger words  it extends the capacity Chunking - It involves auditory processing – your transform the meaningless symbols into auditory information - You use rhyme and rhythm - o It can be determined through song where rhythm can be detected upon recall Interference - This is new information coming into short-term memory store can interfere with information already there, even if it is being actively rehearsed. Recall from STM - Reaction time should reflect time it takes to search through memory - The larger the memory set, the slower the reaction time - Reaction time increases linearly with the number of items in memory - Memory is searched exhaustively whether or not item is present Working Memory - More Accepted view than modal model - Temporarily holds and stores information for use by central executive that performs cognitive task - New and old information is constantly being transformed and combined. - Braddely’s working memory has different components where it has a phonological loop (rehearsing through auditory information) o There is then a central executive where all the memory is being generated towards, o The visuospatial sketchpad adds into it Components of Working Memory - Phonological loop o Rehearsal circuit employing inner speech o Information capacity defined by number of syllables - Visuospatial sketchpad: o Rehearsing images and holding them briefly - Both of these are examples of mental imagery Evidence for Acoustic Encoding - Disruption of recall of visually presented digits when irrelevant speech material is played o The languages that have symbols in numbers can store fewer numbers in memory - Effects of articulatory length on span (not length of representation, but length of rehearsal) Measuring capacity of auditory loop - Like two-second long loop of auditory tape - Digit span test o Chinese speakers remember the most digits o Corresponds to syllable lengths of the names for the digits in each language Evidence for Rehearsal - Hypothesis: subjects hold information in the articulatory loop by saying the word to themselves covertly o They’re not actually saying anything but only in their head - Prediction: if rehearsal is prevented: o STM span should be reduced o Effects due to the use of an articulatory code abolished during rehearsal. Articulatory Suppression - To prevent subjects of using rehearsal, ask them to say to themselves “the” - Span decreases - Phonological similarity effect disappears - Irrelevant speech effect disappears - World-length effect disappears Visuospatial Buffer - We’re storing things through visual memory - There is a different pattern of interference - The capacity is about 4 items - Evidence is shown through: o Visual attention and subitizing experiments: you can immediately assess how many items there are. The error percentage goes up with the amount of items that there are. Central Executive - Limited capacity system - Controls two buffers - Makes the link with long term memory - It is capable of manipulating information: o There is an integration of words during sentence processing o Arithmetical computation o General capacity at treating information in a flexibility way Distinction between STM/LTM - Difference between them may be just the rate of forgetting – process might be similar - There are both ongoing activity, synaptic strength, as well as permanent connections Long-term memory - Nearly unlimited capacity - How are they stored? o Classical view is that if you rehearse things long enough in your short term memory, they will eventually be transformed o Consolidation – transfer from STM to LTM during sleep o Some experiences are remembered better than others o STM and LTM isn’t a good term to use because there are some things that are easier to remember. o Flashbulb effect – what were you doing at a specific point in time o Adrenaline enhances consolidation o Requires protein synthesis (creation of new synapses and new structural connections) Sculpting: - Infants are born with a lot of neurons than they actually certain connections and therefore keep the specific locations - Permanent connectivity of remaining neurons produces the memory - Maintenance is unnecessary Where are memories stored? - Memory is modular: different types of memories are located in different regions of the cerebral cortex - Distributed code in the connection strengths and wiring patterns of neurons - There is no specific location for neurons to exist – therefore, you cannot simply kill of a certain location - Much of the cerebral cortex can be considered “memory” - There are regions of the brain that store particular things o Your motor cortex is you remember all the possible movements that you can possible make  If you chop out the motor cortex then you may just lose the ability to move. Storage limits of LTM - Essentially unlimited capacity but limited by encoding process - Memories decay over time if not refreshed - Different categories of information decay at different rates o Recognition and matching are better than recall Recall of LTM - Ease of recall depends n recency of use (activation) and strength of memory - Recall is more difficult - Activation spreads among semantically related concepts - Strength effects decay more slowly over time than do activation effects Recall with and without retrieval cues - If you have a cue you can recall things more easily. o Words presented with a cue helps recall in terms - There is no need for isolation o There is much better recall with the cue. Retrieval - A retrieval cue is something that is associated with your study type - Items associated with study items at time of learning: o Smell o Context-dependent cues o State-dependent memories (what kind of state were you in) o Mood-depended memories (depressed patients) Memory of Strength - Depends on depth of processing, not just on length of processing (repetition) - When an item is processed more deeply, it is remembered better, even if the person doesn’t intend to memorize it - Depth of processing: o Imagine you have two words: if you are shallow processing them:  If you only focus on the font, you’re not going to focus on the world at all. o A medium type of processing is whether you focus on the rhyme or auditory information of the words o A deep processing is when you need anonymous words to find their nature. o Requesting people to perform all three types of processing helps individuals recall better - The context is very important to strengthen memory o Arrange the items into different groups  do a few things at once, rather than too many. Doing too many things can cause mistakes o The context is important to understand specific instructions for comprehensibility. Recognition/recall distinctions - Source memory v. familiarity o Recall requires source memory o Recognition (multiple choice -= you have the item there, you just need to recognize it) o Organization is more important for recall than recognition  Delay recognition is like recall o Maintenance rehearsal helps recognition but not recall  Recall requires access and decision based on context  Recognition decision or familiarity  You have the connections present, and all you need to do is see them. Retrieval - The fact that retrieval cues help recall but not recognition indicates two stages: o Finding the memory o Evaluating the memory Mnemonics: - A technique to enhance situations that uses familiar associations to enhance the storage and the recall of information in memory - Visual association: link the word with the images o You are increasing the depth of processing - Method of loci – visualize a familiar room or route. Place each item to be remembered in a location and pick it up as you stroll around o There are landmarks and associations - Organizational schemes - Grouping: o There might be rhymes i
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