Cognitive Psychology

1. Cognitive Psychology Lecture 2: Memory September 2008 John Toner

2. Overview of Lecture • Memory (definitions and examples) • Remembering • The Multi-Store Model • Working Memory

3. What is Memory? Information about the past… Details about your life… • Identity • Goals • Faces • Current conversation • This slide

4. Some expert opinion “Memory is the process of maintaining information over time.” -- Matlin (2005) “Memory is the means by which we draw on our past experiences in order to use this information in the present.’ -- Sternberg (1999) Importance of current circumstances “… memory is also the basis for the sense of who we are that each of us carries.” -- Gleitman et al (2004) Why is our sense of self so robust? Most people are certain that they are the same person over days/years

5. Things which involve memory(Illustrating the vast amount of categories and types of information we store!) What is the capital of Italy? How do I ride a bicycle? Where was the last barbecue I was at? How do I get from Clonskeagh to Clondalkin? What song comes next on the album? What does that smell remind me of?

7. Basic process of remembering • Encoding • Storage • Retrieval

8. Encoding Refers to the way in which information comes to be represented Hamlet: “ The spirit that I have seen May be a devil. And the devil hath power T’assume a pleasing shape…”

9. Encoding Hamlet: “ The spirit that I have seen May be a devil. And the devil hath power T’assume a pleasing shape…” • Encode the rhythm/acoustic code • Visually encode the quote • Semantically encode the quote

10. Storage We learn many quotes from the play and do not rehearse them continually. We may not think of them for hours/days but we can still recall them Therefore they must be stored somehow

11. Retrieval Question: Show evidence that Hamlet doubted his father’s ghost Retrieval involves finding and accessing stored memories and processing them so that they are in a form that is useful in the given context

12. The Multi Store Model We know that the actions of thememory system involve encoding, storage and retrieval. But what does the system itself consist of? The Multi Store Model is one theory It looks like this…

13. The Multi Store ModelWaugh & Norman (1965)

14. The Multi Store ModelAtkinson & Schifrin (1968)

15. The Multi Store Model Features of the multi-store model • The multi-store model proposes three distinct parts to memory. Sensory stores, a short term store and a long term store. • In the sensory stores, information and knowledge that comes to us from the senses is stored momentarily. After processing, some of this information is sent on to the short term store. • Some of the information in the short term store is then passed on to the long term store. • The multi store model posits that the long term storage of information often depends on rehearsal, with a direct relationship between the amount of rehearsal in the short term store and the strength of the memory in the long term store.

16. The Multi Store Model Sensory Stores: The persistence of sensory information for a moment after its perception. The information is modality specific. Vision: The Iconic Store Research by Sperling (1960)

17. S W R T Q Z B M P L K Y C N F J T X V R H N G L F C J M

18. The Multi Store Model • Participants in this task could usually report only 4 or 5 of the 12 letters. Sperling’s research also indicated that information in iconic storage usually decays within less than half a second of exposure to the stimulus. • Problem with the experiment: memories of letters decayed before participants could report them. • Averback & Coriell (1961) presented two rows of 8 random letters. A small mark appeared beside one letter’s position just after it appeared. Participants could recall that letter with about 75% accuracy, suggesting that participants had information about 12 of the 16 letters after just 50 milliseconds exposure to them. • This experiment required only one item at a time to be remembered, which meant that information wasn't lost during the time it took participants to report what they saw.

19. The Multi Store Model Sensory Stores: The persistence of sensory information for a moment after its perception. The information is modality specific. Audition: The Echoic Store E.g. Reading & listening Research by Triesman (1964) Dichotic listening task Temporal duration 2 seconds approx.

20. The Multi Store Model The Short Term Store • Atkinson and Schifrin proposed that information that had been attended to in the sensory stores went into a short-term store (also called short-term memory) where it had to be rehearsed before it could go into relatively permanent long term memory. • Short term memory is of limited capacity and is fragile (Remembering phone no. or directions) • Capacity of 5-7 items • Lists of letters/numbers used in experiments • Serial or free recall • Chunks are groups we know already • Last 4 digits in number are same as a familiar one • ALIBM, ALMBI

21. The Multi Store Model The Short Term Store Free-recall memory experiments • In free recall experiments, participants can recall the items presented to them in the list in any ordering. • Typically, these experiments involve people being presented with a series of words, usually consisting of about 15 to 30 words, read a rate of about 1 per second. • Immediately after the task, people are asked to repeat back as many words as they can. • Online free recall task: http://tinyurl.com/j77cq • Example of the task: Glasner and Cunitz (1966)

22. Free Recall as a Function of Serial Position (Glanzer & Cunitz, 1966)

23. The Multi-Store Model Results from Glanzer and Cunitz (1966) • The graph of probability of recall against serial position is a U-shaped curve, known as the serial position curve. • Participants had a higher probability of recall on items that were near the start of the list (i.e. early serial position). This is called the primacy effect. • Participants had a higher probability of recall on items that were near the end of the list (i.e. late serial position). This is called the recency effect.

24. The Multi-Store Model Explaining the recency effect with the MSM • During the presentation of the list of words, people are trying to keep these words in their short term memory. • Short term memory is limited in size to about 7 chunks of information. • Therefore, as new words come into short-term memory, older words must be bumped out of short term memory. • At the end of the task, the only words that are left in short term memory are the ones that have just been heard and therefore have not been bumped out. • This explains why people have better recall of the more recent items.

25. The Multi Store Model Explaining the primacy effect with the MSM • According to the multi-store model, the transfer of information from short term memory into long term memory depends on the amount of attention and rehearsal that the information receives. • Suppose the first word in the list is “doctor”. Short-term memory can give the word the full attention of the rehearsal mechanism. • Suppose that the second word is “sandwich”. Then short term memory must give half its attention to the first word and half its attention to the second word. • When the third word is presented, short term memory will only be able to assign it one third of the attention available. • Words experienced earlier in the list will have more rehearsal, and therefore will have a greater chance of making it to long term memory, and therefore will be more likely to be recalled.

26. The Multi Store Model • Glanzer and Cunitz (1966) also describes a modified version of the free recall experiment. • In the modified version, after the full list of items had been presented to the experimental participants, but before they were asked to recall them, the participants were asked to count backwards from 10. • Counting backwards from 10 involves the use of short term memory, and therefore, according to the multi-store model, the last few words in the list would be bumped out of short term memory • Therefore, the multi-store model would predict no recency effect in this task. • This was found to be the case (see graph on next slide)

27. The Multi Store Model Free Recall as a Function of Serial Position (Glanzer & Cunitz, 1966)

28. The Multi Store Model

29. The Neurology of Memory • Case reported by Milner (1959). A patient ‘H.M.’ suffered on average 10 epileptic seizures per day • Evidence suggested that hippocampus was source of epileptic disorders, so they decided to remove it

30. The Neurology of Memory After surgery H.M.’s intellect and language abilities remained intact. His personality remained largely the same However he suffered massive anterograde amnesia (loss of all memories since surgery) He suffered mild retrograde amnesia (events prior to surgery) The Bourne Identity v Memento

31. Strengths On a conceptual level the model makes sense. We can understand the different functions and recognise the different capabilities of the systems Each store differs in a number of ways, suggesting that they are separate entities Temporal duration Capacity Forgetting mechanisms Brain injury evidence Weaknesses Evidence that the Short term Memory is not unitary (Warrington & Shallice, 1972) Long term memory store holds different types of memories Declarative Episodic Semantic Remembering yesterday 2 + 2 = 4 Non-Declaritive Implicit Songs on radio How to cycle a bike Evaluating the Multi Store Model

32. Evaluating Multi Store Model The MSM is a good place to start modeling,but it does cause some problems • Leads to the assumption that forgetting rates are constant • Assumes that rehearsal is the only route to storage. Is this our experience..? • We can be ready to receive certain info • Person’s mood, wandering imagination

33. Levels of Processing theory Proposed by Craik & Lockhart (1972) Key Idea: The amount of cognitive processing carried out on an item determines its memorability, not the amount of rehearsal.

34. Levels of Processing theory The multi-store model makes two proposals regarding the memorability of a stimulus: • The memorability of a stimulus depends on its being transferred from the short term store to the long term store. • The probability of a stimulus being transferred to the long term store depends rehearsal. Level of Processing theory emphasises Deep, meaningful analysis of a stimulus produces longer lasting memories than superficial, perceptual analysis of a stimulus.

35. Levels of Processing theory Memory is linked with attention Rather than being mental items purposely constructed and stored, memories are after effects of the processing of a stimulus/event

36. Levels of Processing theory Maintenance rehearsal: Repeating previous analysis to prevent decay Elaborative rehearsal: Deeper, more semantic analysis. Only elaborative analysis improves long term memory

37. Levels of Processing theory Craik and Tulving (1975, Experiment 1): Participants answered questions about words presented to them. The questions were designed to engage four different levels of processing from shallow to deep: Graphemic:Is the word in capital letters? Phonetic:Does the word rhyme with ‘weight’? SemanticIs the word a type of fish? Elaborative semanticWould the word fit in the sentence: The man peeled the _____ ?

38. Levels of Processing theory Subsequent recognition of words was better for deeper processing tasks

39. Levels of Processing theory Eysenck (1980) argued that distinctive items will be more readily remembered than typical items Carried out an experiment where participants had to process items that were either distinctive or non-distinctive and process them at a semantic or non-semantic level

40. Levels of Processing theory Eysenck (1980) conditions • Non-semantic / Non-distinctive: Pronounce ‘lamb’ • Non-sem / Distinctive: Pronounce ‘comb’ phonetically • Sem. / Non-distinct.: Processed in terms of meaning • Sem. / Distinct.: Unusual way of processing in terms of meaning

41. Levels of Processing theory Eysenck (1980) results: Non-semantic distinctive words were remembered almost as well as semantic non-distinctive words, highlighting the importance of an items uniqueness in its memorability

42. Strengths Gives importance to the circumstances at time of learning (e.g. environment, attention, previous experience) Explains fMRI data showing increased activity for semantic treatment of stimuli (Gabriele et al. 1996) Weaknesses It is hard to decide the level of processing being used by someone in a given real world situation (see quote on next slide) It does not offer any explanation for implicit learning (coming up!) Levels of Processing theory

43. Levels of Processing theory “ There is a danger of using retention test performance to provide information about the depth of processing, and then using the (alleged) depth of processing to ‘explain’ the retention test performance, a self-defeating exercise in circularity” Eysenck (1978)

44. Contemporary views of memory Schacter & Tulving (1994) drew on many previous theories and research in an attempt to get a more accurate model of memory. We will mow examine their ‘5 memory systems’

46. Working Memory Originally introduced by Baddeley & Hitch (1974) as an improved version of Short Term Memory it has received much attention and is credited with solving many theoretical problems that existed with the original, simple MSM version of what lies between sensory stores and long term memory

47. Working Memory • Baddeley & Hitch wanted to emphasize that temporary storage was not simply a station on the way to long term memory. • Working memory is the way we store information while we are working with it, or attending to it. • These items interact with other cognitive processes (attention, imagery. . .)

48. Working Memory Peach Apple Melon Orange Blueberry Mango Lemon Fig Banana Pineapple Grape Tangerine Raspberry Plum

49. Working Memory London Oslo Rome Berlin Prague Paris Dublin Athens Warsaw Stockholm Madrid Vienna Lisbon Zagreb

50. Working Memory