Prof. Greg Francis 5/23/081AmnesiaIIE 269: Cognitive PsychologyGreg FrancisLecture 21What is wrong with my wife?Fundamental fact There is no method other than objectphysical evidence to verify the accuracy of amemory Memory is a cognitive experience Confidence in the memory is another cognitiveexperience You can be very confident and still be wrong Of course, we must be correct fairly often, orour lives would be a total mess!Amnesia Loss of memory or memory abilities retrograde: forgetting events prior to the injury anterograde: forgetting events after the injury In most cases amnesia is limited in scope andduration like when my brother Joe slipped while playing frisbeeAmnesia Scope and duration Retrograde amnesia for one patientcoma5 monthsto infancy2 yearscoma8 monthsto infancy1 year4 yearscoma16 monthsto infancy2 weeksTimeofaccidentWhat’s wrong with my wife? Nothing! But she cannot remember anything beforeher senior year in high school motor cycle accident complete retrograde amnesiaAn unusual case Side issues Sense of smell Headaches Mild anomia She is able to learn and remember new information Remarkably unaffected by the loss of memories Personality Parents college makes study of retrograde amnesia difficultProf. Greg Francis 5/23/082What is lost? How can someone who loses theirchildhood memories go to college the nextyear? memories cannot be “wiped clean” perhaps they are just not directly accessible forgetting = recall problem?What is lost? More generally, while patients with retrograde amnesia forget theirnames, parents, addresses,… they do not generally forget how to walk, talk,solve problems ==> two types of memory systems» explicit vs. implicit» declarative vs. procedural controversial!Anterograde amnesia Some patients have amnesia that preserves pastmemories but prevents formation of new memories many are long-time alcoholics who did not eat properly» which leads to a thiamine deficiency» which leads to Korsakoff’s syndrome Leonard in MementoPatient HM Surgery on hippocampus (to control epilepsy) anterograde amnesia unable to learn anything new Thinks it is 1965 shocked by age of face in his mirror cannot stand to read newspapers reintroduces himself to doctors, nurses,… Can carry on a conversation!Anterograde amnesics Fairly normal STM digit span (~7 items) But very difficult to extend digit span how many trials to repeat back list correctly?0510152025300 5 10 15 20 25Number of digits to rememberMean trials to criterionControlsPatientsSerial position curve Normal recency Abnormal primacy Consistent with STM-LTM dichotomy01020304050607080901000 5 10 15Item numberPercent correctControlsAmnesicsProf. Greg Francis 5/23/083Patient HM Could learnsome things! E.g.,location ofhospitalcafeteria E.g. mirrordrawingtaskPatient HM Mirror drawing task HM has no knowledge of doing the task before!Learning amnesics Learning in amnesicscannot be measured bydirect measures, mustuse indirect approach study words test» free recall» cued recall» completionABSENTINCOMEFILLYDISCUSSPriming Cued recall and completion are the same, butwith different instructions cued recall: fill in the blanks to make one of thewords in the list completion: fill in the blanks with whatever seemsappropriate (makes no reference to the list)ABS_________INC_________FIL_________01020304050607080Free recall Cued recall CompletionTest typeMean percentControlAmnesicPriming List has basically the same effect on amnesicsas on controls for completion task (amnesicseven a bit “better”)Amnesia-like memory Some aspects of memory seem very much likeamnesia infantile “amnesia” repressed memories Careful studies are difficult to come by becausethe memories (and absence thereof) must beverified remember the “fundamental fact” at the start oftoday’s lectureProf. Greg Francis 5/23/084Infantile amnesia Most people report that they cannot rememberanything that happened to them before age 4years051015200 2 4 6 8Age at time of eventNumber of memories reportedInfantile amnesia Reason is unknown, but the best theory goeslike this… children younger than 4-years-old view the worlddifferently from adults by encoding specificity, one needs to be in asimilar state as study to best recall something adults are very different from children, and thisprevents recall of early memoriesRepression Psychotherapists (e.g. Freud) suggested that muchof childhood is filled with painful events andmemory of the pain is prevented by psychologicaldefense mechanisms (repression) This is very unlikely people do remember painful events well laboratory studies find no evidence of repressed memoriesRepression In a laboratory, showing evidence of repressionrequires being unable to remember something being able to recover the memory through therapy proving that the recovered memory is accurateRepression In therapy, clinicians often claim evidence of repressionwith dream interpretation patterns in symptoms recovering a memory through hypnosis None of these techniques demonstrate a verifiedmemory Among carefully controlled memory research, there isno evidence of repression!Conclusions Retrograde amnesia Anterograde amnesia Learning in anterograde amnesics Infantile amnesia RepressionProf. Greg Francis 5/23/085Next time Study schedules Levels of processing Mnemonics Chunking How to improve your memory without