Cognitive processes

3,962 views

Published on

Behavioral Dentistry
Second Year

Published in: Health & Medicine
0 Comments
2 Likes
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total views
3,962
On SlideShare
0
From Embeds
0
Number of Embeds
1
Actions
Shares
0
Downloads
0
Comments
0
Likes
2
Embeds 0
No embeds

No notes for slide

Cognitive processes

  1. 1. Cognitive Processes: Memory
  2. 2. Hermann Ebbinghaus (1885) • He conducted the first major studies of memory, • Used himself as a subject and nonsense syllables, such as VOL, RIZ, and TAV, as a material to be learned • Measured both learning and retention Savings method or method of relearning: Hermann Ebbinghaus 1850-1909 • Refers to amount of time it takes to learn a list a second time • Original overlearning, or repeating the list of items will result in a saving of both time and errors upon relearning Nature of Forgetting: Initial drop-off followed by slower forgetting overtime • 63% of material is remembered after 20 minutes • 38% after one day • 31% after two days • 25% after 31 days
  3. 3. Forgetting Curve • Illustrates the decline of memory retention in time. • Strength of memory refers to the durability that memory traces in the brain. • The stronger the memory, the longer period of time that a person is able to recall it. Graph of the Forgetting Curve: Humans tend to halve their memory of newly learned knowledge in a matter of days or weeks unless they consciously review the learned materials
  4. 4. Multi-store Model Memory consists of three levels of systems: 1. sensory memory, 2. Short-Term Memory 3. Long-term Memory Sensory memory: • Sense organs have a limited ability to store information for less than a second • Provides brief storage of sensory information, after the stimuli have been removed • Echoic store: Sensory store (hearing system) for auditory information • iconic store; Sensory store for visual stimuli • Visual system processes visual stimuli such as shape, size, color and location, but not meaning
  5. 5. STM (working memory): • Has a limited capacity • sensory memory ___attention____ STM • Holds a limited amount of information for a short period of time • For example: - you keep some piece of information in your head for just a few seconds. - A number to do a subtraction, - an argument you make after a person finishing talking • Ability to hold on to a piece of information temporarily to complete a task. • It causes pre-frontal lobe to be very active.
  6. 6. George Miller (1956) • Identified "magical number of 7 plus or minus 2 as amount of information that can be retained in STM with rehearsal Chunking: • Increases the amount of information that can be retained in STM store • Involves grouping large amounts of information into smaller related units • For example, the mobile number: 966545074077 • 966 545 074 077 • The 7 units of information could be 7 sentences or 7 phrases, rather than 7 words or 7 letters
  7. 7. Long-term Memory (LTM): • Has an unlimited capacity • Information gets into LTM only if it is transferred from STM • This is related to how information is rehearsed • Once information is transferred to LTM, it remains there permanently, • May not remain if brain is compromised severely due to a medical condition or substance use
  8. 8. Atkinson and Shiffrin Model (1968) Multi-store model •12 items •George Sperling (1960) •Partial Report Paradigm 7±2 Miller’s Magic Number (1956)
  9. 9. 10 Information processing model Explanations for how cognitive processes work are known as information processing theories or models. The three- component model of information processing is taught in Educational Psychology. http://www.innovativelearning.com/educational_psychology/cognitivism/index.htm
  10. 10. Hippocampus: • Information is transferred from STM to LTM through hippocampus, • Resembles the curved tail of a seahorse • Old part of cortex, evolutionarily, and is located in the inner fold of the temporal lobe.
  11. 11. Endel Tulving (1986): • He divided LTM into three components: - Procedural - Semantic - Episodic Procedural memory (implicit): • LTM of motor skills, habits, and ways of doing things, such as drive a car • Recalled without conscious effort; • Acquired through observation and practice and are difficult to forget Semantic memory: • LTM of knowledge about language (e.g., what words mean and how they are used), • common sense, and the rules of logic and inference • Social customs Episodic memory (autobiographical memory): • Contains information about events that have been personally experienced • Links to time and place
  12. 12. • Semantic and episodic together are called “declarative memory” Declarative Memory (explicit): • Effortful • Factual Memory • Consciously Available Priming: • Unconscious and that is not episodic, procedure nor semantic • Instance of perception rather than memory • Its role is to enhance identification of objects so that they seem familiar • Exists when the appearance of fragments of a previously encountered target (eg, the first few letters, sketchy outline, first letter of a verse in the Quran) • Increase in ease of doing a task or remembering information as a result of a previous encounter with the task or information.
  13. 13. Emotional Conditioning: • Refers to classical conditioning where the CRs are emotional reactions. • So you can see how you start to build up a way of behaving in the world and responding positively or negatively to certain people, situations, surroundings etc. • Most of the likes and dislikes, the preferences and biases that define ones personality, develop through emotional conditioning • Culture has a significant role
  14. 14. Implicit vs. Explicit Memory • Tasks on left column are examples of implicit memory that do not require executive control. • Brain-damaged or intoxicated humans can still perform them. • Tasks on the right are examples of explicit memory that require some conscious control. They are performed poorly by people who are brain- damaged or drunk • Items in the left column are all indirect forms of memory. • They do not involve a conscious strategy for retrieving information. • If you once learned to read text that is printed backwards, chances are you will be able to do it later, even if you suffer a brain disorder. The same is true of the other tasks on the left. Tasks requiring implicit memory Tasks requiring explicit memory brushing teeth Buying a toothbrush mirror tracing recalling last year reading reversed text paired associate learning doing a word-completion task identifying the head of state singing part of a familiar song writing a term paper
  15. 15. Baddeley’s Model (working memory) • Model of working memory Consists of the following systems: 1. Central executive Slave systems: 2. Phonological loop 3. Visuospatial sketchpad 4. Episodic buffer 1. Central Executive • A flexible and supervisory system responsible for the control and regulation of cognitive processes. • Controls the flow of information from and to its slave systems • Selective attention and inhibition Slave Systems • Short-term storage systems dedicated to a content domain of verbal and visuo-spatial. Auditory/ articulatory
  16. 16. The phonological loop (or "articulatory loop") • Deals with sound or phonological information. Consists of two parts : 1. Auditory memory (inner ear) 2. articulatory (inner voice) • Auditory verbal info enters automatically into the phonological store. • Visually presented language is transformed into phonological code by silent articulation. • Plays a role in acquisition of vocabulary, particularly in the early childhood years. • Vital for learning a second language.
  17. 17. Serial Position Effect (SPE) • Differentiate between STM and LTM • Subjects are given a list of unrelated words to remember and recall in any order • They recall words from the beginning and the end of the list best • SPE occurs because words in the beginning of list transferred to LTM, while words at end of list are still in STM. • Words in the middle are affected by interference from words came before and after, and therefore, are not stored in either STM or LTM • In distracting tasks performed, items at the beginning of the list are well remembered, but those at the end of list are recalled no better than items in the middle or end of list SPE with children and college students: • Young children always have trouble remembering letters in the middle of alphabets • College students have difficulty on exam items targeting information presented in the middle of a lecture (Holen and Oaster, 1976)
  18. 18. Flashbulb Memory: • Refers to memory transported directly from sensory memory to LTM if it receives instant attention • For example, witnessing a fire in your house. • What you do if you are in a movie theater and see smoke coming out? • Used to describe vivid, detailed memories of emotionally-charged or surprising events. • Most accurate when the event has personal significance or consequences • Most people living in the United States can recall what they were doing on the day of September 11, 2001, as it was the day of an extreme event. • 9/11 has still vivid and accurate memories for Americans than Katharina flood in Louisiana (New Orleans), which happened several years after 9/11 • Confidence and accuracy about flashbulb memories fade over time
  19. 19. • Interviewing witnesses of 9/11 after 1 year and then 9 years later will make recollections of event differ substantially from earlier ones, even though certainty and accuracy of memories exist Anterograde and Retrograde Amnesia: • Anterograde and retrograde amnesia illustrate the existence of separate STM and LTM stores Anterograde Amnesia (AA) • People with AA can recall information they learned prior to a trauma, but cannot retain any newly learned information • A person with head trauma cannot remember things occurring afterwards • In AA, patients lose declarative memory, or the recollection of facts, but they retain non-declarative memory, or procedural memory • Patient learns how to talk on phone but does not remember what did he/she have eaten for breakfast
  20. 20. • Person with AA cannot transfer information from STM to LTM Retrograde Amnesia (RA): • RA refers to failure to remember events prior to a particular trauma • For example, patient with head trauma could not remember the accident caused the head trauma • Moderate degree of RA is common in persons with brain concussions, who experience amnesia for events occurred immediately before the injury • Extensive RA is rare and more serious than AA • Neurologically impaired individuals with RA also show AA, though reverse is not true
  21. 21. • One with dissociative amnesia (psychogenic not biologically caused amnesia) displays Retrograde but not Antrograde amnesia • One sign of pseudodementia is Retrograde but not AA Global amnesia. • Some patients with severe cases have a combined form of anterograde and retrograde amnesia • Neuropsychologists debate over whether it is a problem with encoding or retrieval
  22. 22. Schema Theory of Memory: • Schema is a cognitive structure or framework that influences how we look at the world – basically, mental models of how things are • Wyer and Scull (1986) indicate that schema affects how we store and retrieve information • Our memory is filtered through schema • Witness testimony and other reported memories may be biased to fit into preexisting schema
  23. 23. Mnemonic Devices: • Strategies known as mnemonic devices improve memory for information •Method of Loci (ML(: • Loci" is the plural of locus, which means location, or place • Involves associating each item to be remembered with mental images of "places" • For terms that unrelated and difficult to remember, a visual image is most effective • Useful for remembering terms recalled in a specific order • To use ML, first mentally associate each item to be remembered with a visual image • Mentally place these images somewhere in a familiar room or building, such as in corners, and on tables and chairs
  24. 24. • To recall the items, you would mentally walk through the room or building and "look" around at the items • ML exemplifies the use of visual imagery as a tool for remembering verbal information • Visual imagery is highly effective as a memory aid • People who have the ability to form vivid visual images tend to be good at memorizing Here's how it would work if you wanted to remember the following shopping list: 1. Ketchup 2. ice cream • Enter the dining room and picture a bottle of ketchup, dressed in an Asian maid's uniform, sitting on the table. • Go to the kitchen and picture a gallon of ice cream, melting over a hot stove. • Or locate your car’s driver standing by your house door and visualize him wearing a cony hat of ice cream
  25. 25. Eidetic Imagery: ‫تخيلى‬ • In layperson's terms, it is called "photographic memory“ • Patient can study an image for approximately 30 seconds, and maintain a nearly perfect photographic memory of that image for a short time once it has been removed • Some people have an ability to remember very specific details • They have ability to recall images, sounds, or objects in memory with extreme accuracy and in abundant volume. • Able to maintain a mental picture of an object even after it is removed • More common in children than adults • Intensity of recall may be subject to several factors such as duration and frequency of exposure to the stimulus observation , relevance to the person, etc
  26. 26. Context and State Dependence: Encoding Specificity Hypothesis (Tulving &Thomson, 1973) • Indicates that the closer relationship between encoding, storage, and retrieval, the better the recall of information Context Dependence: • When the learning and retrieval environments are the same or similar, your recall of information will be better than when the two environments are different • For example, take exam in your own classroom State Dependence: • When your emotional state is the same during learning and retrieval, you will find it easier to remember information than when your emotional state differs • Being in a depressed mood increases tendency to remember negative events.
  27. 27. Environmental reinstatement effect (long-term vs. short-term) • Long-term: Even after many years of absence, go back to your primary school campus and you will immediately remember things that have already been forgotten • Short-term: Imagine sitting at your desk and deciding to get a drink from the kitchen. • Once you get to the kitchen, you completely forget what you wanted. • If you return to your desk, you will most likely remember what you wanted from the kitchen.
  28. 28. Hippocampus and prefrontal cortex • Hippocampus and prefrontal cortex are involved in context dependent memory. • fMRI demonstrated elevated activation in the hippocampus when contextual information matches from encoding to retrieval, suggesting that the hippocampus may be important in mediating context-dependent memory processes • Activation of the right prefrontal cortex was dependent on contextual information Hippocampus activation in context dependent state pre prefrontal cortex
  29. 29. Example of context dependent memory • Divers in underwater environment were placed under water and listened to a prerecorded list of 36 unrelated words. • After listening to the list of words they were tested on their recall of the words in: - the same environment - the alternative environment. • Results showed that: - words learned underwater were best recalled underwater, - words learned on land were best recalled on land.
  30. 30. Overlearning: • Refers to a person practicing or rehearsing of some material beyond the point of mastery • In learning information that has little inherent (‫)متأصل‬meaning such as multiplication table, overlearning is the most effective memory strategy • Overlearning is best for simple tasks
  31. 31. Forgetting: There are a number of theories of forgetting such as: A. Trace Decay: • Refers to information in LTM that are deteriorated or forgotten unless it is accessed or rehearsed • This explains the loss of information from STM B. Interference: Types of interference: 1. Retroactive inhibition (RI) • RI occurs when a new experience interferes with recall of an earlier one • For example, anatomy lecture of today interferes with information of anatomy lecture of last week. • So you experience difficulty recalling anatomy information of last week
  32. 32. Experimental vs. control group: • Experimental group learns list A and list B and recalls B. • Control group learns list B and is asked about recalling list B List A List B_________experimental group___control group orange okra learn A and B and learn B and banana biscuit recall A recall B grape garlic • Control group recall B better than experimental group. • Sleeping following the learning of new information demonstrate better recall than remaining awake after learning the same information 2. Proactive Inhibition (PI) • Occurs when previous learning interferes with more recent learning. • For example, anatomy lecture of last week interferes with information of anatomy lecture of today. • So you experience difficulty recalling anatomy information of today
  33. 33. C. Repression: • Information is not recalled due to its emotional significance • An active inhibition of recall, rather than a true loss of information, accounts for observed instances of forgetting • Repression of memory is seen as a dynamic and unconscious process • For example, a severe fright or trauma may be repressed because recall of trauma is disturbing • 19% of sexual abuse victims had forgotten but later recalled sexual abuse (loftus et al, 1994) Hypnosis: • Research shows that Memories retrieved under hypnosis tend to be less accurate than other memories • Nonetheless, Individuals who recall information while under hypnosis have greater confidence in their memories as compared to controls • In some research studies, hypnotized subjects were reluctant to admit that their memories were inaccurate even confronted with clear evidence demonstrating this to be the case
  34. 34. Anatomically Correct Dolls: Used for assessment of childhood sexual abuse and by parents of identifying inappropriate touching: 1. Sexual abuse victims do respond differently to these dolls than non victims (e.g., among victims sexualized play is more common) 2. Dolls facilitate memory for details of sexual abuse 3. Useful in helping shy, embarrassing, or verbally limited to talk children about incidents of abuse male/female identification (with depicted genitals) mom is going through her pregnancy CONTROVERSIAL
  35. 35. Metacognition: • Refers to thinking about thinking or knowing about knowing • Refers to person’s awareness about his or her own cognitive state and processes Metacognition involves: • Evaluating one’s own cognitive skills • Using strategies to increase the efficiency of memory or learning • The ability to determine how much knowledge you have and need • Using mnemonics in rereading or organizing information • Develops in early adolescence or later, in conjunction with Piaget’s formal operation stage • Found in adult intelligence
  36. 36. Zeigarnik Effect (1938) • Bluma Zeigarnik assigned her subjects simple puzzle-like problems • Subjects allowed to finish half the problems but interrupted and kept from finishing the other half • Later, subjects were asked to recall all tasks • 68% of unfinished tasks were recalled vs. 43% of finished tasks • Interrupting a subject in middle of task has the effect of leaving him or her in a state of tension and disequilibrium • To replace the tension, subject wants to complete the task, and thereby to remember unfinished tasks better than completed ones

×