1. Chapter 4: Working Memory

2. Graduate Programs in Clinical Psychology Presentation by Dr. Natalie Smutzler and Dr. Tina Pittman-Wagers Wednesday, October 7 5pm to 7pm Humanities 1B90 Free Pizza

3. Working Memory (short-term memory): brief, immediate memory for material currently being processed; also coordinates ongoing mental activity Short-term memory evolved into working memory

4. Capacity of short-term memory George A. Miller (1956). The magical number seven, plus or minus two: Some limits on our capacity for processing information. The Psychological Review Miller proposed that we can hold 5-9 pieces of information for a brief period of time » 5-9 random numbers or letters » CIAFBINFLMTVCBS (15 letters) » CIA FBI NFL MTV CBS (5 acronyms) » 3034921701 (10 numbers) » (303) 492-1701 (6 part phone number) » Chunk: the basic unit of short-term memory, consisting of several components that are strongly associated with one another

5. Why Miller’s paper is important: Brought together seemingly unrelated data Suggested a limitation to human information processing Showed how humans transcend this limitation » By chunking information Showed information science can be applied to human thinking

6. Duration of Short-Term Memory What is the duration of short-term memory? Brown, Peterson, & Peterson technique » How long can a person hold a few items in memory without repeating the items? » Give the person 3 unrelated numbers, letters or words to remember » Prevent the person from repeating the items by counting backwards by 3s from a 3-digit number » Result: Steady decline in memory over time Most information is gone in about 20 seconds

7. Serial position effect: items near the beginning and end of a list are recalled best Those in middle are recalled worst Primacy effect: better recall for items at the beginning of a list Recency effect: better recall for items at the end of a list

8. An explanation of serial position effect: Recency effect: » Items at the end of the list are in STM Subjects report first the items at the end of the list Recall about 5-9 items at the end of the list STM’s capacity Recency effect disappears after 20 sec if subjects count backward by 3s before recall Primacy effect: » Items at the beginning of the list are more are more likely to be rehearsed and so stored longer Subjects report first the items at the end of the list Recall about 5-9 items at the end of the list This does not explain all serial position effects » E.g., remembering the presidents of the US

9. Atkinson and Shiffrin’s (1968) Model of Memory Sensory Memory Visual : iconic store – Usually lasts less than a second (can last a couple seconds) Auditory: echoic store – Lasts about 2-4 seconds Short-Term Memory (STM) Lasts about 20 seconds – Can be extended by rehearsal Holds 5-9 chunks of information Long-Term Memory Permanent memory store

10. Atkinson and Shiffrin Model of Memory

11. Some problems with the classical view of short- term memory (1) Pronunciation time » STM holds the number of items that a person can pronounce in 1.5 to 2.5 seconds Not necessarily 5 to 9 chunks » So, STM can hold more short words than long words Because takes less time to pronounce short words WITTECHNOLOGY ENDENCYCLOPEDIA CUBUNIVERSITY BOXCONVENTIONAL

12. Problems with STM (cont.) (1)Pronunciation time (cont.) » People speaking different languages seem to have different digit spans Digit span: number of digits that can be held in STM Digit Span Pronunciation time (average) Chinese:9.9 digits265 milliseconds English:6.6 digits321 milliseconds Welsh:5.8 digits385 milliseconds -An inverse correlation between pronunciation time and digit span

13. Problems with STM (cont.) (2) Semantic similarity Originally concluded that STM uses an acoustic (sound) code » Based on mixing up letters that sound alike (e.g., B, V), not look alike (e.g., O, Q) Even when presented visually » But further research showed sound is not solely used for STM processing Proactive interference: people have trouble learning new material because previously learned material interferes with new material

14. (2) Semantic similarity (cont.) Subjects perform a Brown, Peterson & Peterson task View 3 letters, count backwards by 3s, stop and give letters 4 trials given; each with 3 letters – E.g.: XCJ HBR TSV KRN Subjects do progressively worse at remembering letters as trials progress STM is not cleared after each use » Old information is affecting it Proactive interference occurs

15. But, if give numbers instead of letters on the 4 th trial (e.g., 529), subjects do almost as well as on the first set of letters (XCJ) Release from proactive interference: proactive interference is reduced by switching to a new stimulus category, producing increased recall This also works with meaning » E.g., Instead of letters and numbers, fruits, vegetables, flowers, meats, occupations used Further from category (fruits – occupation) bigger the release from proactive interference So, STM is not just chunking and coding information by sound, STM’s capacity depends on how long it takes to say the word, and the word’s meaning » These and other findings resulted in STM evolving into a more complex concept – working memory

16. Working Memory Alan Baddeley Reformulated STM into working memory during the 1970s » Not just a store for items until put into LTM or lost » Actively works on information Not just passively storing information » Focus on what it accomplishes

17. Working Memory

18. Working Memory (cont.) Why Baddeley concluded that there are separate stores for auditory and visual information: People can do 2 working memory tasks simultaneously without much interference if one is acoustic and the other is visual – More than 9 chunks of information are processed » Shouldn’t happen if can hold only 5-9 chunks of information

19. Working Memory (cont.) Baddeley concluded that two stores exist in working memory: (1) Phonological Loop: stores a limited number of sounds for a short period of time – 2 functions: (i) Storage of acoustic information (ii) Rehearsal of information – Phonological loop uses a sound code – Brain imaging studies show the left hemisphere is active during phonological loop tasks

20. (2) Visuospatial sketchpad: stores visual and spatial information – Stores images from visual perception – And visual information derived from verbal descriptions – Brain imaging studies show right hemisphere becomes active during tasks requiring the visuospatial sketchpad

21. (3) Central Executive: integrates information from the phonological loop, visuospatial sketchpad, and the episodic buffer – Plays a big role in attention, planning strategies, and coordinating behavior – Suppresses irrelevant behavior – So, decides what to do next And what not to do – Limited in how much it can do at any one time – Doesn’t store information itself – Associated with frontal lobes Demonstrated by people with frontal lobe damage performance on Rey-Osterreith Complex Figure Test

22. Rey-Osterreith Complex Figure

23. Working Memory Episodic Buffer: a temporary storehouse for gathering and combining information from the phonological loop, the visuospatial sketchpad, and long-term memory – Baddeley added the episodic buffer 25 years after the other 3 parts of working memory

24. What part of working memory is involved in daydreaming? – Stimulus independent thoughts: streams of thoughts and images that are unrelated to current sensory input Includes more than daydreaming – Experience Sampling Methods: Person reports behavior, feelings, and thinking throughout the day following randomly-occurring prompts Used in daydreaming research

25. Daydreaming (cont.) Strategy: occupy part of working memory with processing and see if daydreaming occurs – If daydreaming occurs, that part of working memory is not necessary for daydreaming

26. Daydreaming (cont.) Results: – If subjects perform simple repetitive task Using phonological loop or visuospatial sketchpad – Daydreaming occurred – If task required attention and planning Little daydreaming – Conclusion: daydreaming requires central executive but not phonological loop or visuospatial sketchpad