Memory 3265

1. Memory 3265 • Course website address • http://www.yorku.ca/npark/memory_w_12

2. Introduction and History of Memory Research • History • Ebbinghaus (1885) is credited with being the first person to scientifically study memory • prior to Ebbinghaus relatively little was written about about memory

3. Introduction and History of Memory Research • History • however, people did write about factors affecting memory performance • attentiveness and rehearsal aid memory • Aristotle (4th Century BC) • proposed laws of associationism. Most important is the law of contiguity-- two events or experiences occurring closely in time will come to be associated with each other

4. Introduction and History of Memory Research • History • Romans (e.g., Cicero) and others were concerned with using mnemonics to assist memory • mnemonics generally remember something new by pairing it with already known information • developed the method of loci. In this method a person places items to be memorized in particular locations well known to the memorizer

5. Introduction and History of Memory Research • History • Ebbinghaus (1885) published Memory: A contribution to Experimental Psychology • first experimental study of memory; inspired by Fechner’s work on the psychophysical study of sensation

6. Introduction and History of Memory Research • History • experimental procedure of Ebbinghaus • Materials. Used nonsense syllables (CVC) to try and study acquisition and memory for brand-new stimuli • Participant. Ebbinghaus • Procedure. Presented nonsense syllables one at a time at a fixed rate of presentation. Studied list until he could recall entire list in serial order without error (method of complete mastery)

7. Introduction and History of Memory Research • History • experimental procedure of Ebbinghaus • Procedure (cont’d). Ebbinghaus was concerned with the rate of forgetting as a function of the time interval between initial learning and his attempt to recall the list. If he made one or more errors, Ebbinghaus restudied list until he could recite the list perfectly. The dependent variable was the savings score, ie, the time or trials saved in learning list again. Example, initially took 1500 seconds to learn list; took 600 seconds to relearn list; savings = 900/1500 = 60%

8. Introduction and History of Memory Research • History • experimental procedure of Ebbinghaus • Results. Ebbinghaus produced his famous forgetting curve. There is a precipitous drop in retention shortly after a list was acquired

9. Ebbinghaus’ forgetting curve

10. Introduction • History • the tradition of Ebbinghaus • highly controlled experiments • simple stimuli • quantifiable dependent measures • reaction to its restrictiveness • Gestalt psychologists, Bartlett, and cognitivists

11. Introduction • History • Cognitive tradition (William James) • In his classic text, principles of psychology, James distinguished between different types of memory • Habits were 1 type of memory that mediated skills such as walking, writing, and singing • James believed these resulted from a concatenation of reflex mechanisms and pathways, which could combine to produce complex behaviors • Two other forms of memory according to James were: • Primary memory – now called short-term working memory • Secondary memory – now called long-term memory

12. Introduction • History • Cognitive tradition (William James) • James did not explicitly distinguish between habit and memory • Bergson (1911) proposed that representation of the past has two distinct types of memories – habits and memories • As we shall see, the distinctions proposed by James and Bergson continue to be made

13. Introduction • Other traditions • ecological validity • neuropsychology • Ecological validity • argues that the Ebbinghaus tradition is concerned with unimportant problems with little applicability to real world problems

14. Introduction • Ecological validity (cont’d) • this approach, spearheaded by Neisser (1978, 1982) is controversial • and there are strong critics of this approach (e.g., Crowder)

15. Introduction • Other traditions (cont’d) Neuropsychology • Neuropsychology: study of disorders of perception, memory, language, thought, emotion, and action in neurological patients • Gall proposed theory of cortical localization in which individual cognitive functions are mediated by specific brain regions • No real evidence for this idea because he examined bumps on skull, which he related to cognitive functions (e.g., pride, vanity, language, and speech)– now called phrenology

16. Introduction • Other traditions (cont’d) Neuropsychology • Broca 1861 • 51 year old man; lost power to speak (“Tan” was one of the only speech sounds he could make) • Paralyzed on right side with a loss of sensitivity • Mouth not paralyzed; he could understand speech • Autopsy revealed damage to left inferior part of frontal lobe • on the basis of a brain-behaviour case study he claimed that language is localized to the inferior part of the left frontal lobe

17. Introduction • Broca (cont’d) • two important parts of claim • 1. Language can be dissociated from other cognitive functions • 2. Language function can be localized to a particular brain region

18. Introduction • Carl Wernicke (1894) • Reported case of a patient who could produce speech, but could not understand speech • Damage to left temporal cortex suggested that this was site for speech comprehension • this approach to understanding cognitive function led to the rise of the diagram makers (1860 - 1905)

19. Introduction • Logic of diagram makers • identify distinct syndromes, then attempt to theoretically link the different syndromes • for example, they identified what they believed were several distinct types of aphasia • Broca’s aphasia--speech is nonfluent; ie, short phrases, poor melodic content, limited grammatical form • Wernicke’s aphasia-- speech is fluent, but comprehension is impaired

21. Lichtheim’s Neuropsychological model of language Function Word concept elaboration 3 Auditory word centre (Wernicke) Motor word representations (Broca) Auditory input Speech motor output

22. Criticisms of diagram makers • Work of diagram makers has a contemporary flavour and is now appealing to 20th century eyes • Work was attacked for following reasons • 1. Postulated that the functions they hypothesized could be precisely localized; evidence do not support this claim • 2. Psychological concepts were inadequate; e.g., aphasia was a word-based deficit; evidence suggests that syntax is an important component of the deficit

23. Criticisms of diagram makers • Work was attacked for following reasons • 1. Postulated that the functions they hypothesized could be precisely localized; evidence do not support this claim • 2. Psychological concepts were inadequate; e.g., aphasia was a word-based deficit; evidence suggests that syntax is an important component of the deficit • 3. Did not carefully and systematically observe the patients on which theoretical ideas were based

24. Group study approach (1940-1970) • Rejected the single-case approach to neuropsychology in favour of the group study approach • clinical observations became an insufficient basis for theoretical speculation

25. Cognitive Neuropsychology • Use information processing models to describe cognitive function; these models are very similar to Lichtheim • note: you can conceptually ‘lesion’ information processing models • returned to the use of the case study • however, an experimental approach was used • attempt to use case studies to discriminate between different models of normal function

26. Cognitive Neuropsychology • Memory findings by early neuropsychologists • early investigators studied anterograde amnesia – impaired ability to recall newly learned information • Retrograde amnesia – loss of memories acquired prior to onset of brain trauma

27. Cognitive Neuropsychology • Ribot (1882) • Reviewed a large number of cases of retrograde amnesia following brain damage and head trauma • Memories acquired remotely prior to insult were better retained compared to memories acquired more recently before insult • This result is called Ribot’s law or the law of regression • Concluded that memories require time to be organized and consolidated

28. Cognitive Neuropsychology • Alzheimer (1906) • Reported the case of a patient with dementia now known as Alzheimer’s disease (AD) • Showed that 2 important symptoms of AD were: anterograde amnesia and retrograde amnesia (graded; i.e., remote memory better retained than more recent memory)

29. Introduction: Memory • What sorts of functions are subserved by memory? • Who am I? • If you have no memory of the events that you have experienced (autobiographical memory), then it would be difficult to answer this question • What do I know? • Semantic knowledge about the world

30. Introduction: Memory • What sorts of functions are subserved by memory? • Memory for actions • procedural memory; memory is expressed by performance rather than by recollection or verbal description • how do you tie your shoelace? • How do you play a musical piece • how do you use a hammer

31. Introduction: Memory • What sorts of functions are subserved by memory? • How do I learn? • Why do I forget? Is it functional?

32. Introduction: Memory Methodology • Distinctions • Learning refers to the the acquisition of new skills and information • Memory refers to the retention of what has been learned over time

33. Introduction: Memory Methodology • The memory process is composed of three main phases: • encoding or registration: transformation of information presented to a person into a form that can be retained • retention: storage of information • retrieval: recollection or remembering of stored information

34. Introduction: Memory Methodology • Incidental versus intentional memory • Explicit memory • conscious recollection of previous experience • e.g., tell me your telephone number • e.g., try to recall when you first decided to take this course • explicit memory can be intentional or unintentional • e.g., remembering an argument you had with your friend is explicit, but may be unintentional

35. Introduction: Memory Methodology • Measuring explicit memory • recall (free or cued) • recognition • Implicit memory • indirect memory test; conscious recollection not involved • e.g., mere exposure effect; word stem completion

36. Introduction: Memory Methodology • Episodic versus semantic memory • episodic memory is memory for events or episodes; it is stored in terms of its autobiographical reference to already stored information • semantic memory is the memory necessary for language; it is a mental thesaurus, organized knowledge a person possesses about words, and other verbal symbols and their meaning

37. Introduction: Memory Methodology • Independent variables • factor that influence performance of some dependent measure • in memory research it is a factor that affects memory performance

38. Introduction: Memory Methodology • Types of independent variables • organismic: relatively permanent characteristics of an individual that affect memory performance • e.g., age, intelligence, health • antecedent variables: sleep, drugs, time of day

39. Introduction: Memory Methodology • Types of independent variables (cont’d) • task variables: • instructions (e.g., intentional vs incidental) • presentation conditions (e.g., rate of presentation) • stimulus variables (e.g., picture, word, type of word) • context in which task occurs

40. Introduction: Memory Methodology • Types of dependent variables • accuracy • number of items recalled, recognized • types of errors made • scoring criterion: strict…(need to operationalize) • What do you do about guessing? • speed • order in which items were recalled

41. Introduction: Memory Methodology • Some standard memory tasks • serial learning: recall items from a list in the exact order in which they were presented • free recall: recall as many items from a list in any order • cued recall: present cue-target pairs at study; at test present cue and have participant recall target

42. Introduction: Memory Methodology • Some standard memory tasks (cont’d) • Recognition test • multiple-choice test. Participant selects which of 2 or more alternative choices is correct • true-false test (yes/no test)

43. Non-traditional memory tasks • Autobiographical memory • memory of old TV shows • famous faces

44. Non-traditional memory tasks • Implicit memory has become increasingly popular • amnesics remember information when tested using implicit memory procedures; however, amnesics are unable to remember this information when they are tested using explicit memory procedures

45. Non-traditional memory tasks • Warrington and Weiskrantz (1970) • tested amnesics and controls on explicit and implicit memory tasks • subjects were presented a list of words to study; amnesics were much inferior to controls in their explicit recall and recogniton of the studied words • also tested memory on two implicit memory tasks (word fragment identification and word stem completion e.g., cha----); on these two implicit memory tasks amnesics performed as well as controls

46. Non-traditional memory tasks • Conclusion • amnesics may have selective damage to that part of the memory system that mediates explicit recollection of stored information