1: Brown-Peterson Paradigm 2: Intro to the Working Memory Model

Transcription

1 1: Brown-Peterson Paradigm 2: Intro to the Working Memory Model Psychology 355: Cognitive Psychology Instructor: John Miyamoto 4/23/2015: Lecture 04-4 This Powerpoint presentation may contain macros that were used to create the slides. The macros aren t needed to view the slides. If necessary, you can disable the macros without any change to the presentation.

2 Outline Mention Friday section & essay quiz Duration of information retention in STM The Brown-Peterson Paradigm Retroactive & proactive interference (a cause of forgetting) Proactive interference & the Brown-Peterson Paradigm Introduction to the Working Memory (WM) Model Contrast between the STM model & the WM model Three components of the WM model: Phonological Loop (PL); Visuospatial Sketch Pad (VSP); Central Executive (CE) Evidence that WM has a PL component Lecture probably ends here Psych 355, Miyamoto, Spr '15 What Causes Forgetting from WM/STM? 2

3 What Causes Forgetting from WM/STM? Why is information lost from STM? How long does information last in STM without active processing? Two hypotheses Decay representations of information simply "fall apart." Interference other information "bumps" information out of STM. Brown-Peterson paradigm an attempt to measure how long information is retained in STM without active processing. The Brown-Peterson paradigm will be discussed on the next slide. General Conclusion: Without active processing, all information is lost after seconds. What causes the loss of information? Interference - one very likely cause. Decay - hard to prove convincingly that decay occurs; maybe it does. Psych 355, Miyamoto, Spr '15 The Brown-Peterson Paradigm - Example 3

4 Brown-Peterson Paradigm Brown-Peterson paradigm an attempt to measure how long information is retained in STM without active processing. The Brown-Peterson task is this past week s Coglab. Example of the Task: Remember three letters: Count backwards by 3 s from the given number: Stop counting and report the letters when the experimenter tells you to do so. P N R 108 Duration of delay is different, e.g., 5 second, 10 second, 15 seconds,..., on different trials. Psych 355, Miyamoto, Spr '15 Brown-Peterson Paradigm Summary of the Task 4

5 What is the Purpose of the Brown-Peterson Paradigm? Brown-Peterson paradigm an attempt to measure how long information is retained in STM without active processing. Remember three letters, e.g., P N R" Count backwards by 3's from a given number Report the letters after a delay Goal: Measure decay characteristics of STM. Counting backwards by 3 s is an example of articulatory suppression. Assumption 1: While you are counting backwards, you cannot rehearse P N R. Assumption 2: Counting backwards by 3's does not interfere with retention of "P N R". Later when we discuss working memory, we will say that counting backwards by 3 s suppresses activity in the phonological loop (PL). Psych 355, Miyamoto, Spr '15 Results for Brown-Peterson Task Averaged Results 5

6 Results for the Brown-Peterson Paradigm Delay in Seconds IMPORTANT FACT: These results are averaged over many trials. Superficially, the results support the hypothesis that without active processing, almost all information is lost after about seconds. Psych 355, Miyamoto, Spr '15 Keppel & Underwood: Reanalysis for 3 rd & 18 th Trial 6

7 Keppel & Underwood s Reanalysis of Brown-Peterson Results Delay in Seconds Delay in Seconds Delay in Seconds Panel (b): Performance on the 1 st trial of Brown-Peterson task. Panel (c): Performance on the 3 rd trial of Brown-Peterson task. Performance at 18 second delay gets worse as subject performs more memory trials! Psych 355, Miyamoto, Spr '15 Same Graph Hypothesis That Proactive Interference Causes Forgetting 7

8 Keppel & Underwood s Reanalysis of Brown-Peterson Results Delay in Seconds Delay in Seconds Delay in Seconds Why does performance at 18 second delay get worse as subject performs more memory trials? Proactive interference explained on next slide Psych 355, Miyamoto, Spr '15 Interference Definition; Proactive & Retroactive Interference 8

9 Interference a Cause of Forgetting Interference as a cause of forgetting something you learn or already know makes it difficult to remember something else. Retroactive Interference (RI): New learning interferes with recall of previous learning. Example: What did you see when you walked to school 7 days ago? Everything you have seen since then interferes with access to that memory. Example: Julie used to go out with Tom and now she goes out with Ted. Memory of Julie/Ted interferes with memory of Julie/Tom. Proactive Interference (PI): Old learning interferes with recall of new learning. Example: If you already play tennis, it is harder to learn to play badminton than if you already play basketball (not tennis). Example: It is hard to remember where I parked my car today because I have many memories of parking my car in various places. Psych 355, Miyamoto, Spr '15 Experimental Design for Wicken s Exp Showing Release from PI 9

10 Forgetting in Brown-Peterson Paradigm Is Due in Part to PI Simplified Version of Figure 6.6 (p. 157): Wicken's Study of Influence of Proactive Interference on Brown-Peterson Task Wicken s experiment uses the Brown-Peterson paradigm. Experiment has 3 groups, but only two are important. Psych 355, Miyamoto, Spr '15 Same Slide Emphasis Rectangle on Fruit Group 10

11 Forgetting in Brown-Peterson Paradigm Is Due in Part to PI Simplified Version of Figure 6.6 (p. 157): Wicken's Study of Influence of Proactive Interference on Brown-Peterson Task Fruit Group: Every trial requires subject to remember 3 fruit. Meat Group: Trials 1 3 require remembering meat words. Trial 4 requires remembering fruit words. Psych 355, Miyamoto, Spr '15 Results of Wicken s Experiment 11

12 Forgetting in Brown-Peterson Paradigm Results in Part from PI % Recalled After 20 s Delay % Recalled After 20 s Delay Fruit Group Trial 1: banana, peach, apple Trial 2: plum, apricot, lime Trial 3: melon, lemon, grape Trial 4: orange, cherry, pineapple (same category) Same Meat Group Trial 1: salami, pork, chicken Trial 2: bacon, hot doc, beef Trial 3: hamburger, turkey, veal Trial 4: orange, cherry, pineapple (switch category) Fruit Group Remember list of fruits after remembering other lists of fruits. Meat Group Remember list of fruits after remembering lists of meats. Psych 355, Miyamoto, Spr '15 Same Graph Without the Colored Boxes 12

13 Forgetting in Brown-Peterson Paradigm Results in Part from PI % Recalled After 20 s Delay % Recalled After 20 s Delay Fruit Group Trial 1: banana, peach, apple Trial 2: plum, apricot, lime Trial 3: melon, lemon, grape Trial 4: orange, cherry, pineapple (same category) Mean Group Trial 1: salami, pork, chicken Trial 2: bacon, hot doc, beef Trial 3: hamburger, turkey, veal Trial 4: orange, cherry, pineapple (switch category) Fruit Group Remember list of fruits after remembering other lists of fruits. Meat Group Remember list of fruits after remembering lists of meats. Psych 355, Miyamoto, Spr '15 Same Graph: Define Release from PI 13

14 Forgetting in Brown-Peterson Paradigm Results in Part from PI % Recalled After 20 s Delay % Recalled After 20 s Delay PI: Previous trials with same category (fruit or meat) interferes with STM retention on current trial. Release from PI: Improved STM retention on trial where PI no longer influences performance. Fruit Group Remember list of fruits after remembering other lists of fruits. Meat Group Remember list of fruits after remembering lists of meats. Psych 355, Miyamoto, Spr '15 Summary: What Causes Forgetting from WM/STM? 14

15 Conclusion re Forgetting in the Brown-Peterson Paradigm Delay in Seconds Delay in Seconds Delay in Seconds Proactive interference is a major cause of forgetting in the Brown-Peterson paradigm. Brown-Peterson paradigm attempts to measure decay of memory in STM, but the measurement is confounded with PI (proactive interference). Psych 355, Miyamoto, Spr '15 Bottom-Line re Forgetting in STM 15

16 Bottom Line re Duration of Storage in WM/STM To keep information in WM/STM, you need to actively process the information. Phonological rehearsal & forming mental images Associating contents of WM/STM with information in LTM (thinking) Without active processing, information in WM/STM is lost after seconds. In everyday life, information may be lost from WM/STM even more quickly, e.g., after a few seconds, if some new information interferes with the contents of WM/STM. Why is information lost from WM/STM? Interference well-established cause of forgetting from WM/STM. Decay no one has yet proved definitively that decay does or does not occur. Psych 355, Miyamoto, Spr '15 Overview of WM versus STM 16

17 Overview of the STM and WM Models Short-Term Memory (STM) STM is a single component Main theoretical issue: How much information can be stored in STM and how long does it last? Working Memory (WM) WM has multiple components Main theoretical issues: How is information represented in WM? How is information manipulated in WM? o The issue of the duration and quantity of information storage is still important for WM,... but question of how WM manipulates information is the central focus of research. Psych 355, Miyamoto, Spr '15 Modal Memory Model 17

18 Modal Model of Memory (circa 1970) Control Processes Input Sensory Memory Short-Term Memory Long-Term Memory Output: Speech/Actions Psych 355, Miyamoto, Spr '15 Diagram for the Baddeley-Hitch Working Memory Model 18

19 Baddeley-Hitch Working Memory (WM) Model Think of the diagram to the right as an expansion & revision of the standard STM model. 1. Phonological Loop (PL) Storage of sounds Rehearsal Manipulation of verbal information 2. Visuospatial Sketch Pad (VSP) Storage & manipulation of visual images and spatial information. 3. Central Executive (CE) Directs activity within the PL or VSP. Coordinates activity between PL, VSP, and LTM. Psych 355, Miyamoto, Spr '15 Same Slide Without the Emphasis Rectangles - END 19

20 Baddeley-Hitch Working Memory (WM) Model Think of the diagram to the right as an expansion & revision of the standard STM model. 1. Phonological Loop (PL) Storage of sounds Rehearsal Manipulation of verbal information 2. Visuospatial Sketch Pad (VSP) Storage & manipulation of visual images and spatial information. 3. Central Executive (CE) Directs activity within the PL or VSP. Coordinates activity between PL, VSP, and LTM. Psych 355, Miyamoto, Spr '15 What Justifies the Hypothesis: PL is Part of WM? 20

21 What Justifies the Hypothesis: PL Is Part of WM? Summary of Evidence for PL (Phonological Loop) Phonological similarity effect: Lists of words that are similar in sound are harder to remember than lists of words that sound different, even with a visual presentation of stimuli. Example 1: Remember the list, D B C T P G (harder) Example 2: Remember the list, K F Y L R Q (easier) Word length effect: People are better at remembering lists of short words than lists of long words. Articulatory suppression experiments Neuropsychological evidence (later - not in this lecture) Psych 355, Miyamoto, Spr '15 Demo of the Phonological Similarity Effect 21

22 Demo of Phonological Similarity Effect: Memory Span for Words On each trial, you will see a sequence of words presented one after the other. Your Task: Write down all of the words in the order in which they were presented. For example, if you see ORANGE LOOSE GRIP TUESDAY Write down: ORANGE, LOOSE, GRIP, TUESDAY. Note that ORANGE, TUESDAY, GRIP, LOOSE is incorrect. On each trial, make a mental note of how hard it was to do the task. Psych 355, Miyamoto, Spr '15 Fixation Point 22

23 Word Span Trial with 5 Words: How Hard Is This? * Note to Self: The following slides advance automatically on a timer, i.e., don't advance the slides manually. Psych 355, Miyamoto, Spr '15 Next: On Click Display Stimulus Words on a Timer, 1 Slide per second 23

24 Digit EASE Psych 355, Miyamoto, Spr '15 24

25 Digit GONE Psych 355, Miyamoto, Spr '15 25

26 Digit SING Psych 355, Miyamoto, Spr '15 26

27 Digit TOP Psych 355, Miyamoto, Spr '15 27

28 Digit CRISP Psych 355, Miyamoto, Spr '15 28

29 What Were the Words? Correct Answer: EASE, GONE, SING, TOP, CRISP Remember how hard was that task. Next: Repeat task but with different stimulus words. Psych 355, Miyamoto, Spr '15 Fixation Point 29

30 Word Span with 5 Words: How Hard is This? * Note to Self: The following slides advance automatically on a timer, i.e., don't advance the slides manually. Psych 355, Miyamoto, Spr '15 On Click, Display Stimulis on Timer, 1 Slide per Second 30

31 Digit RAKE Psych 355, Miyamoto, Spr '15 31

32 Digit FATE Psych 355, Miyamoto, Spr '15 32

33 Digit TASTE Psych 355, Miyamoto, Spr '15 33

34 Digit BREAK Psych 355, Miyamoto, Spr '15 34

35 Digit BAIT Psych 355, Miyamoto, Spr '15 35

36 What Were the Words? Correct Answer: RAKE, FATE, TASTE, BREAK, BAIT Which word list was harder to remember? List 1: The words are not similar in sound. List 2: The words are similar in sound. List 2 is harder to remember. This is the phonological similarity effect. Psych 355, Miyamoto, Spr '15 Theoretical Analysis of the Phonological Similarity Effect 36

37 Interpretation of Phonological Similarity Effect Phonological similarity effect: Memory span is smaller for similar sounding words than for dissimilar sounding words. What does this show about working memory? Basic assumption of PL: One way that people maintain information in STM is by rehearsing the sound of words. Prediction: Similar-sounding words are more confusable in a sound-based rehearsal. Therefore memory span should be smaller for lists of similar-sounding words because the similarity in sound causes errors. Prediction is confirmed. This evidence supports: (a) PL exists; (b) people use rehearsal to maintain information in WM/STM. Psych 355, Miyamoto, Spr '15 Demo of the Word Length Effect 37

38 Thursday, April 23, 2015: The Lecture Ended Here Psych 355, Miyamoto, Spr '15 38