CHAPTER 6 – MEMORY MODULE 6.1 REMEMBERING After you have mastered the information in this unit, you will be able to: Describe the basic processes and stages of memory Explain the constructivist theory of memory Describe flashbulb memories Discuss the factors that influence the accuracy of eyewitness testimony Discuss the controversy regarding recovered memories of childhood sexual abuse Key Terms and Concepts: Memory Memory Encoding Memory Storage Memory Retrieval Retrieval Cues Encoding Specificity Principle Context-Dependent Memory Effect State-Dependent Memory Effect Three-Stage Model Sensory Memory Sensory Register Iconic Memory Eidetic Memory Echoic Memory Short-Term Memory (STM) Working Memory Chunking Maintenance Rehearsal Phonological Loop Visuospatial Sketchpad Central Executive Long-Term Memory )LTM) Consolidation Elaborate Rehearsal Semantic Network Model Levels-of-Processing Theory Declarative Memory Semantic Memory Episodic Memory Retrospective Memory Prospective Memory Procedural Memory Implicit Memory Explicit Memory Priming Task Constructionist Theory Memory Schema Flashbulb Memories Misinformation Effect I. Human Memory as an Information Processing System A. Memory—the system by which we retain information and bring it to mind B. Memory encoding—taking information in 1. Converting information into a form we can store 2. Acoustically—encoded by sound 3. Visually—encoded by mental image 4. Semantically—encoded by meaning Memory storage—retaining information in memory (see Memory Stages, below) Memory retrieval 1. Accessing stored information to make it available to our consciousness 2. Availability may be a function of retrieval cues 3. Encoding specificity principle—retrieval better when surrounding cues similar to those present when information learned (Tulving, 1983) 4. Context-dependent memory effect—retrieval best when in same setting 5. State-dependent memory effect—retrieval best when in same physiological or psychological condition Memory Stages—Three-Stage Model A. Sensory memory 1. Very brief sensory information storage (few seconds at most) 2. Sensory register—temporary storage device for sensations 3. Iconic memory a. Holds sensory visual images b. Lasts fraction of a second 4. Eidetic imagery (photographic memory) 5. Echoic memory a. Holds sensory auditory input b. Lasts three or four seconds maximum B. Short-term (working) memory—STM 1. Holds information up to 30 seconds 2. Most information stored acoustically 3. “Working memory” because we are actively processing 4. “Magic number”: 7 (plus or minus 2) units can be stored 5. Chunking—more remembered when restructured into units 6. Maintenance rehearsal—repeating information to keep longer in STM 7. Three-component model of memory a. Phonological loop—stores verbal/speech-based information b. Visuospatial sketchpad—stores visual and spatial information c. Central executive—coordinates both and interfaces with LTM C. Long-term memory (LTM) 1. Retains information for a longer period of time 2. Essentially unlimited in capacity 3. Consolidation a. Converting less stable STM information into LTM b. Needs at least twenty-four hours after learning to occur c. Both REM sleep and slow-wave sleep crucial to this process 4. Information stored on basis of meaning (semantically) 5. Elaborative rehearsal—focus is on meaning of material 6. Semantic network model a. Leading model regarding LTM organization b. Information held via interlinking concepts c. Spreading activation—one concept triggers recall of related others 7. Levels-of-processing theory a. Information held best depending on depth of level at which it is encoded or processed b. Elaborative rehearsal more effective than maintenance rehearsal The Contents of Long-Term Memory A. Declarative memory (explicit memory) 1. “Knowing that” 2. Takes conscious effort to bring to mind 3. Categories (organized by type or time frame) a. Semantic memory—compare to our storehouse of information b. Episodic memory—personal experiences, personal “story” c. Retrospective memory—memory of past events d. Prospective memory—keeping in mind future events B. Procedural memory C. D. II. III. 1. 2. 3. 4. 5. IV. V. “Knowing how” Engaged without conscious effort Less easy to explain verbally Involves motor or performance skills Types of procedural memory a. Implicit memory—memory evoked without intentional effort (e.g., pleasant memories when hearing a favorite song) b. Explicit memory—intentional effort needed to bring it to mind (e.g., remembering the capital of a state or country) The Reliability of Long-Term Memory A. Constructionist theory 1. Memories not a perfect copy of past experience 2. Memories created from integrated pieces of stored information 3. Possibility that memories can be distorted B. Flashbulb memories 1. Vivid, lasting, highly detailed memories 2. Derived from extremely salient past events 3. Also may be inaccurate, distorted (like other LTM) C. Eyewitness testimony 1. Possible that it is inaccurate, distorted 2. Misinformation effect—suggestions lead to inaccuracies in recall 3. Accuracy involves the following factors: a. Ease of recall—slower response indicates less accurate b. Degree of confidence—more confident eyewitness not necessarily more accurate c. General knowledge about a subject—more knowledgeable witness is more accurate regarding that particular subject d. Racial identification—more errors made when identification crosses racial lines e. Types of questions—leading, suggestive questions result in more errors from witnesses than open-ended questions Exploring Psychology: Are Recovered Memories Credible? A. Often a lack of corroborating evidence B. Some memories may be genuine; some surely are false or distorted C. Very difficult to differentiate between false vs. true MODULE 6.2 FORGETTING After you have mastered the information in this unit, you will be able to: Discuss the major theories of forgetting Explain how recall is related to the methods used to measure it Discuss amnesia and its causes Key Terms and Concepts: Decay Theory Savings Method Massed vs. Spread Practice Effect Interference Theory Retroactive Interference Proactive Interference Overlearning Serial Position Effect Primacy Effect Recency Effect Retrieval Theory Tip-of-the-Tongue (TOT) Phenomenon Repression Recall Task Recognition Task Amnesia Retrograde Amnesia Anterograde Amnesia Childhood Amnesia Dissociative Amnesia I. II. III. IV. V. VI. Why Do We Forget? A. Some people more forgetful than others B. Variety of explanations for normal forgetting Decay Theory A. Belief that memory is a trace that fades over time B. Hermann Ebbinghaus (1885) used nonsense syllables to test himself and memory C. Ebbinghaus forgetting curve—most information lost shortly after learning (66 percent in first day) D. Savings method—much less time to relearn forgotten information E. Massed vs. spaced practice effect—more information retained when learning sessions spread out over time F. Weakness in decay theory: 1. Forgetting over time is quite uneven 2. Seems to be related to meaningfulness of original material Interference Theory A. Belief that memory loss is due to occurrence of other similar events B. Retroactive interference—what learned now interferes with previous learning C. Proactive interference—what learned now interferes with what will be learned in the future D. Steps to minimize memory disruption from interference: 1. Sleep after learning 2. Practice (repeat) new information when first learned (may want to overlearn) 3. Schedule breaks between learning sessions (such as between classes) 4. Avoid studying similar topics in close succession E. Serial position effect 1. Tendency to recall first and last items in a list best 2. Interference most likely to occur with items in middle 3. Primacy effect—recalling items best when they are given first 4. Recency effect—recalling items best when they are given last Retrieval Theory A. Forgetting results from breakdown in retrieving stored memories B. Encoding failure 1. Memory cannot be retrieved because information was never originally stored (never encoded) 2. We encode only as much information as we need 3. Distinct, unique events tend to be remembered 4. Similar events tend to be encoded as a group (based on common features) so more difficult to distinguish among these C. Lack of retrieval cues 1. Information encoded but not accessible 2. Insufficient distinctive cues to help us retrieve 3. Tip-of-the-tongue phenomenon—partial recall; may be associated with general word retrieval difficulty Motivated Forgetting A. Sigmund Freud—memories are not forgotten, just kept hidden (repression) B. Repressed information is threatening or unpleasant C. Repression—defense mechanism that helps protect from overwhelming anxiety D. Concept is controversial since there is evidence that refutes Measuring Memory A. What is remembered may in part depend on how it is assessed B. Recall task—reproduce information that has been stored in memory 1. Free recall—remember as much as possible; order does not matter 2. Serial recall—recall items or numbers in a particular order 3. Paired-associates recall—after word pairs are memorized, one word is presented (must retrieve associated word) C. VII. Recognition task 1. Select correct answer from among choices given (like a multiple-choice test) 2. Recognition memory nearly always better than recall Amnesia—Severe Type of Memory Loss A. Types of amnesia 1. Retrograde amnesia a. Loss of memory regarding past events b. May involve disruption of consolidation process c. Loss is greatest for more recent events 2. Anterograde amnesia—difficulty or inability to store new memories 3. Childhood amnesia a. No recollection of earliest childhood years b. May be due to lack of sufficient organization of pre-verbal memories in the brain or immature brain structures for LTM B. Causes of amnesia—physical or psychological 1. Physical causes a. Blows to the head, degenerative brain diseases (such as Alzheimer’s) b. Blood vessel blockage, infectious diseases, alcoholism c. Early detection critical to successful treatment 2. Psychological causes (dissociative amnesia)—memory is traumatic, too disturbing for conscious awareness (condition may be reversed) MODULE 6.3 THE BIOLOGY OF MEMORY After you have mastered the information in this unit, you will be able to: Describe where memories are stored in the brain Discuss the role of the hippocampus in memory Define LTP, and explain its possible role in memory formation Explain what scientists have learned about the genetic basis of memory Key Terms and Concepts: Engram Neuronal Networks Long-Term Potentiation (LTP) I. II. Brain Structure in Memory: Where Do Memories Reside? A. Karl Lashley (early twentieth century)—search for engram 1. Believed to be the physical trace or record of a memory (in the brain) 2. Research on rats—removing portions of cortex 3. Rats still retained memory, regardless of what removed 4. Conclusion is memory is stored throughout brain B. Neuronal networks—current technology reveals memory stored in intricate circuitry of neural constellations (in brain) C. Hippocampus 1. Portion of limbic system in brain 2. Responsible for converting STM into long-term declarative (semantic, episodic) memory 3. Is not involved in procedural memory processes 4. Temporary storage only of new declarative memories D. Other brain structures 1. Thalamus—if damaged, results in amnesia 2. Amygdala—helps encode emotional experiences Strengthening Connections Between Neurons: The Key to Forming Memories A. Research on sea snail (Aplysia) by Eric Kandel (1995) B. Shows memory formation involves biochemical changes (at level of synapse, the connection between neurons) C. Long-term potentiation (LTP) 1. III. Connections between nerve cells (e.g., in brain) become stronger as a result of repeated stimulation 2. Stronger synaptic connections mean neuron communication easier 3. LTP believed to be a factor in STM to LTM conversion Genetic Bases of Memory A. STM-LTM transformation in brain requires various proteins B. Production of these proteins regulated by certain genes MODULE 6.4 APPLICATION: POWERING UP YOUR MEMORY After you have mastered the information in this unit, you will be able to: Discuss ways in which you can improve your memory I. II. Using Mnemonics to Improve Memory A. Mnemonic—device for improving memory B. Types of mnemonics 1. Acronyms and acrostics—use first letter of a series of words to form a word or a verse 2. Popular sayings and rhymes (such as “30 days hath September…”) 3. Visual cues, visual imagery—leave a visual note or create an associated visual image 4. Chunking—recombine larger amounts of information into a useable or familiar unit General Suggestions for Improving Memory A. Pay attention—focus on task, have quiet surroundings B. Practice—especially with elaborative rehearsal C. Use external memory aids—a reminder note is fine! D. Link time-based tasks to external cues E. Mentally rehearse—plan and visualize your tasks in advance F. Enhance context-dependent effects G. Control stress H. Adopt healthy habits—healthy diet and exercise help memory