Foundations of Perception and Cognition - Short-Term and Working Memory: Part 1 - PDF

 This presentation contains images owned by third-parties. They can be used for educational purposes in this presentation. The following copyright warning must be provided prior to presenting them: Copyright Warning This material has been copied and co...

 This presentation contains images owned by third-parties. They can be used for educational purposes in this presentation. The following copyright warning must be provided prior to presenting them: Copyright Warning This material has been copied and communicated under the Statutory Licence pursuant to s113P of the Copyright Act 1968 for the educational purposes of the University of Adelaide. Any further copying or communication of this material by you may be the subject of copyright protection.  Part 1 (Lecture 1) Part 2 (Lecture 2) What is Memory? Working Memory: Overview An Early Model of Memory The Phonological Loop Short-Term Memory (pre-1970’s) What Use is The Phonological Loop? Short-Term and Working Memory The Visuo-Spatial Sketchpad? What Use is The Visuo-Spatial Sketchpad? The Central Executive and Episodic Buffer Working Memory: Evaluation  Recommended Reading This week’s recommended reading is: Goldstein Chapter 5: Short-Term and Working Memory I discuss most major topics* but don’t always cover them in the same order. I also cover interesting topics that are not in the chapter *Example: I leave out the content from the ‘Working Memory and the Brain’ section, but please do read this section Definition and Research Focus Memory is the processes involved in retaining, retrieving, and using information about stimuli, images, events, ideas, and skills after the original information is no longer present (Goldstein, 2018, p.130) Memory researchers study issues such as: 1. How many memory systems exist 2. How each type of memory functions (e.g., capacity, forgetting, accuracy) 3. What factors harm or enhance memory (e.g., drugs, mood) 4. How memory changes with age 5. The brain structures involved in remembering What Is Memory For? We use memory to remember many things, including:  Ourselves (e.g., our name, likes, dislikes)  Others (e.g., their faces, names, relationship to us)  Events (e.g., what we have done, what others have done)  General Knowledge (e.g., what is 2 + 2? What is the capital of France?)  Actions (e.g., writing, riding a bicycle)  Locations (e.g., workplace, home) Atkinson and Shiffrin’s Modal Model of Memory Atkinson and Shiffrin (1968) suggested we have three memory systems: They felt sensory information first enters Sensory Memory (SM) and is stored for less than a few secs. Attention sends it to Short-Term Memory (STM), which is a limited capacity temporary store. Rehearsal (thinking about it) keeps it alive in STM. When rehearsal stops, it is quickly forgotten or transferred to Long-Term Memory (LTM), which is a (potentially) permanent store. When information in LTM is needed, retrieval processes send it back to STM for use. Problems with the Modal Model Atkinson and Shiffrin (1968) correctly identified three memory systems, but their model was an oversimplification We now know each system has subsystems with unique functions (storing images, storing words) Over the next two weeks, you will learn about Some of the short-term/working memory some of STM and LTM’s subsystems subsystems (names are in bold)  Definition “The ability to hold in mind, in an active, highly available state, a small amount of information” (Johansen, 2008) How is it studied? Participants study a series of stimuli for a couple of secs each (e.g., random numbers, letters, If you were given directions and immediately words) and then immediately recall them* tried to recall them, you would be using STM *Stimuli needs to be presented long enough so participants can consciously process it, but no so long that it ends up in LTM  How is it studied? Prior to the 1970’s, researchers primarily studied recall of verbal (language-based) stimuli such as letters and numbers: This is called Verbal STM*  Visuo-spatial STM was rarely studied (i.e., memory of images or locations) If I flashed this grid onscreen for 2 secs and On the next few slides, I discuss early research on then asked you to recall which squares were Verbal STM’s capacity, duration, and forgetting black, I would be testing visuo-spatial STM *I will later explain that visuo-spatial STM is very different to verbal STM, but researchers did not realise until the 1970’s Verbal STM Capacity Jacobs (1887) conducted an early STM study using the digit span test He read a short sequence of random letters or digits to school-aged participants, and they had to immediately recall this sequence in the correct order. For example: 4, 7, 3, 8, 1, 9, 6, 0, 5, 2 Participants could repeat 7.3 letters and 9.3 numerals (on average), suggesting people can hold 7 – 9 items in verbal STM. Thus, Verbal STM has a very limited capacity  Verbal STM Capacity Jacob’s (1887) digit span test is still the main method of studying Verbal STM today The test is also used in the diagnosis of many clinical disorders (e.g., dementia, Alzheimer's Disease, dyslexia) and is core to all IQ tests, as If you go into a Clinical Psychology-related career, STM / Working Memory underpins abilities such you will use the Weschler Memory Scale for as reading and performing maths in our minds* patient assessments. Digit span is test within it *This is something we did not know prior to the 1970’s. It is discussed in more detail later Verbal STM Capacity As you probably realised from Jacob’s (1887) study, the type of verbal stimuli used matters Baddeley et al.’s (1975) confirmed this in a study where participants heard five 1, 2, 3, 4, or 5 syllable words and them immediately recalled them. Participants could recall:  90% of 1 syllable words (e.g., zinc, school, maths)  40% of 5 syllable words (e.g., hippopotamus, tuberculosis, university) This is the word-length effect. More shorter words can fit into STM, so we recall more of them  Verbal STM’s Capacity and Age Gathercole et al. (2004) found Verbal STM increases from the age of 4 until 14 Park et al. (2002) found Verbal STM decreases between the age of 25 and 85 So, Verbal STM capacity is likely at its peak when people are between 18 and 30 years old Digit span across age groups from here* *The figure shows results from tests where digits were presented aurally or visually, and were recalled forwards or backwards  Increasing Verbal STM’s Capacity Miller (1956) famously showed LTM can be used boost Verbal STM’s capacity:  If pieces of information in Verbal STM have a meaningful association, LTM can group that information together to form a single chunk* His study’s found STM can hold 7 (±2) chunks of This list has 10 letters but can be information (so between 5 and 9 chunks) broken down into 3 chunks *This is why we can often recall 20+ words, if they are associated. We can combine words into larger meaningful chunks (e.g., phrases) and remember 7 (±2) larger chunks (e.g., possum, child, ringtail, young = ringtail possum; young child) Increasing Verbal STM’s Capacity Ericsson et al. (1980) examined whether we can increase our Verbal STM capacity They tested the digit span of a student called S.F. He initially had a digit span of 7. After 230 hrs of practicing the test, his digit span increased to 79! How was this possible? See the next slide Increasing Verbal STM’s Capacity S.F. was a keen runner and used knowledge of race times (stored in LTM) to assist STM and create large chunks of information  Example: If hearing 3594, he associated it with the time Roger Bannister took to run the first sub-4 min mile in 1954 (3 min 59.4 sec) When S.F. was tested on other types of stimuli, he performed normally (e.g., letters)  Increasing Verbal STM’s Capacity Think S.F.’s digit span of 79 was impressive? 8 x World Memory Champion Dominic O’ Brien once recalled 2808 random playing cards in row! In class, we will watch a 2.5 min video where Dominic does a digit span test and explains how he uses LTM and ‘chunking’) to boost his STM 8 x World Champion Dominic O’Brien The Visual Imagery chapter in Goldstein discusses some techniques for boosting memory Verbal STM Storage Duration We can store 7 (±2) chunks of information in Verbal STM, but how long can it stay in there for? Information is retained in Verbal STM whilst we thinking about it (called rehearsal) When we stop thinking about it (i.e., rehearsal Rehearsing numbers for a stops) it quickly leaves STM … but how quickly? Verbal STM digit span test? Verbal STM Duration Peterson and Peterson (1959) presented participants with lots of trigrams (e.g., TPZ) Recall was allowed after delays of 3 to 18 secs. Rehearsal was prevented during delays by having participants repeat a three-digit number aloud Without rehearsal, forgetting started immediately 3 sec delay / no rehearsal: 80% recall and almost all items were forgotten within 18 secs 18 sec delay / no rehearsal: 12% recall  Verbal STM Forgetting STM has a limited capacity. If STM is full, new information must compete with existing information for space, causing either:  Displacement: New information pushes existing information out of mind  Interference: Existing information stops new information entering our minds Information may also be forgotten from STM due to decay (fading with time), but this is a minor cause (e.g., Berman et al., 2009) A Recap of Pre-1970’s Beliefs/Research Atkinson and Shiffrin‘s (1969) Modal Model of Memory was the first major memory model and it suggested we have one STM system STM studies of the time focussed on Verbal STM (recall of digits, letters, words) There was no real discussion about what we use STM for (simply remembering lists?) In the early 1970’s, two major developments changed our understanding of STM’s structure and function….. Development 1: Cognitive Neuropsychological Research Cognitive neuropsychological research on patients with brain lesions identified a double-dissociation between Verbal STM and Visuo-Spatial STM, suggesting STM has at least two systems: Patient and Study Lesion Cause Verbal STM Visuo-Spatial STM Patient KF Motorcycle Shallice and Warrington (1970) accident 125 Italian patients Various De Renzi and Nichelli (1975) (e.g., strokes) Development 1: An Example Patient Patient N.A.’s brain was damaged by a miniature fencing foil when he was 22 years old His Verbal STM was damaged, but his Visuo- Spatial STM (and aspects of LTM) were intact In class, we will watch a 3 min video of N.A. receiving a Verbal STM by Larry Squire N.A.’s real name was kept confidential Development 2: STM Shown To Underpin Abilities Baddeley and Hitch (1974) speculated that STM underpins cognitive abilities such as: Reading Mental math Problem solving Conversations They felt STM works to support cognitive abilities and designed an experiment to show this…… Alan Baddeley and Graham Hitch Development 2: STM Shown To Underpin Abilities Baddeley and Hitch (1974) had participants perform two tasks simultaneously: 1. A Verbal STM task: Repeating aloud a random sequence of up to 8 numbers. Verbal STM’s capacity is 7 (±2). Thus, the more numbers participants had to remember/repeat, the more their STM was filled 2. A cognitive task: Reasoning, learning, or language comprehension ▪ An example reasoning task was: A is preceded by B = (B > A)? True or False If STM underpins cognitive tasks but is full, participants should struggle performing the cognitive tasks  A Demonstration (Part 1) Before discussing Baddeley and Hitch’s (1974) findings, I will conduct a demonstration to help you understand their research better On the next slide are some maths questions. Answer as many as you can in 30 secs This is the control condition as your Verbal STM capacity is not being used up by something else Later, you will try it again when your Verbal STM capacity is being used up by something else Are you ready?  A Demonstration (Part 2) On the next slide are more maths questions. Answer as many as you can in 30 secs This time, you will use up some Verbal STM capacity by repeating the following numbers over and over whilst you complete the maths questions: 4, 5, 8, 2, 6, 1 Practice repeating them over and over now so you remember them. In 5 seconds, I will move to the next slide, and you can start the maths problems Are you ready? Development 2: STM Shown To Underpin Abilities Baddeley and Hitch (1974) found the following: As participants Verbal STM became increasingly full, their performance on the cognitive tasks increasingly slowed (e.g., see the purple line) They argued STM continually works to support cognitive abilities, so a more appropriate name for it is Working Memory Performance during the reasoning task The Working Memory Model Based upon the evidence from… 1. Patients with brain lesions (see earlier) 2. Their own study (just described) … Baddeley and Hitch (1974) proposed a new model of STM called The Working Memory Model, that had several systems and emphasised STM’s role in underpinning cognitive tasks In the next lecture, you will learn about this model….. By the end of Short-Term and Working Memory: Part 1, you should be able to 1. Explain what memory is, what it is used for 2. Describe Atkinson and Shiffrin’s (1969) Modal Model of Memory and explain its three components 3. Explain STM is, how much information it can hold, how long it holds it for, and why information is forgotten from it. 4. Explain why Atkinson and Shiffrin’s (1969) Modal Model of Memory was incorrect when describing STM and why the Working Memory model replaced it