SHORT TERM & WORKING MEMORY

Memory Ability to call to mind information that is no longer present Different types of information Different sensory systems Different time scales

Remembering begins with acquisition. gathering information and placing it into memory The next aspect of memory is storage. holding information for later use The final phase is retrieval. draw information from storage and use it

Memory One way to frame learning and memory Acquisition Storage Retrieval Analogy to creating, storing, and opening a computer file

Memory This view is problematic for at least two reasons New learning is grounded in previously learned (stored) knowledge Effective learning depends on how the information will be later retrieved

Outline, Ch 5 Modal Model Baddeley’s Working Memory Model Sensory store Sperling (1960) Short Term Memory Limited in Capacity Chase & Simon (1973) Limited in Duration? Brown Peterson Task Waugh & Norman (1965) Wickens et al – Release from proactive interference Baddeley’s Working Memory Model Phonological loop Visuospatial sketchpad Episodic buffer Central Executive

The Modal Model of Memory (Atkinson & Shiffrin, 1968) Short-term memory (STM) Long-term memory (LTM)

The Modal Model of Memory (Atkinson & Shiffrin, 1968) Sensory store Short-term memory Long-term memory Attention Control Processes Retrieval

The Modal Model of Memory (Atkinson & Shiffrin, 1968)

Sensory Store Brief register of all perceptual input Large volume of info Very rapid decay e.g., Persistence of vision Retention of perception after the image itself is gone

Sperling (1960) demo whole report partial report delayed partial report

Sperling (1960) design IV1: IV2 (partial report only): DV: Delay Reporting condition Whole Partial IV2 (partial report only): Delay 100 ms 300 ms 1000 ms DV: % of items correctly reported

Sperling (1960) demo Display is identical, only reporting procedure differs Whole report is poor, but why? Partial report answers that question

What does Sperling (1960) tell us about the sensory store? It is limited in duration, not capacity. Lots of information gets in, but fades quickly Sensory store Short-term memory Long-term memory Attention Control Processes Retrieval

The Modal Model of Memory (Atkinson & Shiffrin, 1968) Sensory store Short-term memory Long-term memory Attention Control Processes Retrieval

Short Term Memory Representation Process Fixed capacity storage Information enters storage until it is full Once full, new information bumps out old information Control processes operate on information in STM 1 2 3 4 5 6 7 2 3 4 5 6 7 8

Short Term Memory Digit-span task Participant asked to remember digits List is increased until memory fails Maximum number is the digit span

Short Term Memory Control processes operate on information in STM Sensory store Short-term memory Long-term memory Control processes operate on information in STM Rehearsal Strategies used to make a stimulus more memorable Integrating with knowledge STM holds both information from sensory store and from LTM Attention Control Processes Retrieval

Let’s Try It

F BIV IPG NPC BS recall

FBI VIP GNP CBS recall

F BIV IPG NPC BS FBI VIP GNP CBS

Working Memory Chunking The ability to condense information Requires effort Reduces load Does not increase memory capacity TNTXLAWVNYND refers to a repackaging of the information held in working memory A series of letters HOPTRASLU can be chunked as the syllables HOP, TRA, SLU Working memory can hold 7 plus-or-minus 2 chunks of information Effort and attentional resources are required to repackage the input Does not increase the size of working memory itself

STM is limited in capacity Limited capacity (7+2; 4; 5+3) chunks Chunk = integrated unit of information Chunk is determined by participants experience or strategy Chase & Simon (1973) http://youtu.be/rWuJqCwfjjc

Evidence for Chunking Chase & Simon (1973) Shown chess board for 5 seconds then asked to reproduce it IVs: skill level board type DV: accuracy reproducing board

Is STM limited in duration?

Brown-Peterson task: ABC 49 (“49 46 43 40 37 34…”) Recall “ABC” Read three letters, then a number Begin counting out loud backwards by three’s After a set time, recall three letters ABC 49 (“49 46 43 40 37 34…”) Recall “ABC”

Let’s Try It CHG 18 recall FSA 37

Peterson & Peterson (1959) when rehearsal is prevented, short-term memory is about 15-20 seconds, but why? This doesn’t tell us where interference is coming from. It could be from items. It could be from time.

Peterson & Peterson (1959) Interference from other materials (the number counting) or Forgetting / decay over time

Time versus items (aka duration vs. capacity) Waugh & Norman (1965) 2 4 3 6 5 1 8 9 1 Single items presented Note when at item repeated and report the item that followed the 1st presentation of the repeated item ( “8”) varied # items between repetitions varied time between repetitions

Waugh & Norman (1965) Both have 4 intervening items, but were presented a 1 item/sec for white and 4 items/sec for black Evidence that the decrease in accuracy is due to interference from other material, not passage of time They control the number of items and the amount of time separately.

Is STM limited in duration? What appears to be a limit in duration is actually due to confusion from other items (called interference)

Working Memory An alternative to the short term store notion of short term memory A status Limited size Easy entry Easy retrieval Fragile

Working Memory Experiments support the division between WM and LTM Presented a long series of words (e.g., 30) Perform free-recall afterward Look at the position in the list (serial recall)

Working Memory Serial Position Demo

Primacy effect Better memory for first few items Long-term memory Memory rehearsal allows transfer from WM to LTM Primacy effect With free recall, participants are likely to remember the first few items in the list. Based in long-term memory During list presentation, the first few items receive the most memory rehearsal and are transferred from WM to LTM.

Recency effect Better memory for the last few items Based on working memory With free recall, participants are likely to remember the last few items in the list. Based in working memory At the end of list presentation, the last few items are currently in working memory and are often the first items to be reported.

30 seconds not enough to wipe out recency Another task is needed to do so Thirty seconds of filled delay displaces the last few items from working memory. This eliminates the recency effect. Thirty seconds of unfilled delay does not change the recency effect.

Slow presentation aids pre-recency items Recency effect the same Slowing down the presentation of the list allows for more rehearsal of all items. This improves all parts of the curve that reflect LTM, that it, all items except for the last few Memory for the rest of the list is better

Primacy associated with hippocampus Working memory associated with perirhinal cortex Memory for the items at the beginning of the list (but not the end) is associated with activity in the hippocampus.

Working Memory Virtually all mental activities require working memory (WM) Reading Goal-driven behavior Some tasks demand more WM resources than others Individual differences in WM capacity predict some cognitive abilities

Baddeley’s Working Memory Model 1. Phonological Loop 2. Visuospatial Sketchpad 3. Episodic Buffer 4. Central Executive

Baddeley’s Working Memory Model

1. Phonological Loop For maintenance of verbal information (i.e., repeating a phone number over and over until you dial it) Fixed size (size differs for different people)

Evidence that the Phonological Loop is a fixed size Reading rate of an individual corresponds to WM capacity of that individual Faster auditory processing is associated with higher working memory capacity.

Keep this matrix in mind Keep this matrix in mind. I will read you a list of instructions detailing how to fill in the boxes of the matrix. Pass out sheets with the above grid to students and have them keep the sheet face down. Half the class looks at a blank screen while the other half looks at something “interesting”. The instructions are as follows: “In the square with the black star, put a one. In the next square to the right, put a two. In the next square to the right put a three. In the next square down put a four. In the next square to the left put a five. In the next square down put a six. In the square to the left put a seven. In the next square up put an eight. In the next square to the left put a nine. In the next square down put a 10.

Solution 1 2 3 9 8 5 4 10 7 6 Results?

2. Visuospatial Sketchpad For maintenance of spatial / visual information Image processing Mental rotation Mental calculations Maintaining the visual representation of the grid while also looking at the picture is difficult. The blank group does better because the VSS does better because they don’t have to work as much to maintain the info in WM.

Evidence for VSS Toms et al (1994) Varied what participants looked at while hearing the instructions Measured % of correctly filled in boxes Eyes shut - 85% Blank screen - 84% Pattern - 69% The pattern occupies the VSS, the subject is not able to use it to complete the task Visual information interferes with visual information. There is a fixed capacity for the VSS. New info that comes in overwrites the old info. Just like the phonological loop.

3. Episodic Buffer integrates information and may assist in getting information to long-term storage

4. Central Executive Representation Process Coordinates and controls the other three Representation Defn:The mental structure of information in the external world that preserves relevant and necessary information Verbal info maintained in PL Visual info maintained in VSS Process Defn:The method used to retrieve the representation and use it to make the relevant decision PL & VSS are independent, fixed capacity systems that actively work on verbal & visual information, respectively and allow that information to interact with LTM. The CE coordinates the PL & VSS

Working Memory Executive control Control sequences of thought and action Select and launch responses Plan and set goals Break habit or routine Executive control refers to processes that are needed to: Control the sequences of our thought and action Select and launch responses Plan and set goals Resist falling into habit or routine

Working Memory One metaphor for working memory is a loading dock Mechanically transfers input to and from long-term memory A better metaphor is a librarian Actively categorizes, catalogs, and cross-references new material

Working Memory Reading span Captures active nature of working memory Participant reads sentences and remembers the last word in each sentence The number of words remembered is the reading span A measure that captures the active nature of working memory Participant reads a series of sentences and must remember the last word in each sentence The number of sentence-final words that can be remembered is the operation span.

Working Memory Operation span Another measure of working memory Is equation true or false? Remember a word Number of words remembered is the operation span Another measure that captures the active nature of working memory Participant determines whether an equation is true or false, and must remember a word paired with each equation The number of words that can be remembered determines the operation span.

Working Memory Reading span and operation span correlate strongly with Test performance Reasoning Reading ability

Working Memory Helpful to have larger WMC Helps us understand when and how WM is used What are we measuring with intelligence tests? Correlations obtained with active measures (operation span) but not with static measures (span task)

Conceptual Differences Between STS & WM? WM = interaction between the components (CE and VSS ;CE and PL) WM has several processes; STS has one.

Baddeley’s Working Memory Model Representation Defn:The mental structure of information in the external world that preserves relevant and necessary information Verbal info maintained in PL Visual info maintained in VSS Process Defn:The method used to retrieve the representation and use it to make the relevant decision PL & VSS are independent, fixed capacity systems that actively work on verbal & visual information, respectively and allow that information to interact with LTM. The CE coordinates the PL & VSS

Clive Wearing http://www.learner.org/resources/series150.html 11. Clive Wearing, Part 2: Living Without Memory http://youtu.be/KosOuLEa22k Sensory store? Short term or working memory? 64

WM is limited in size Getting information into WM is easy Getting information out of WM is easy Contents of WM are fragile LTM not limited LTM less fragile More difficult to transfer info

LONG TERM MEMORY Clive Wearing Very successful conductor until he contracted viral encephalitis in his 40s