BCS 111 Unit 6.3

Short term memory encoding strategies

• Chunking

• Story making

• Rehearsal

A more comprehensive framework than STM: working memory

• “Includes short-term memory AND other processing mechanisms that help to make use of short-term memory”

• Not just about storage, but also processing

• Incorporates the role of attention in memory encoding

• Assumes different processing and storing mechanisms based on the nature of input

Working memory: Processing input + temporary storage

Working memory - Phonological loop

Why so important

• Rehearsal in memory recall tasks

• Free recall of words: Fast presentation → less time to rehearse → poorer recall of initial items (reduces primacy effect)

(cont)

• Free recall of words:

  • Slow presentation → more time to rehearse → better recall of initial items

How to prevent rehearsal 

Add another distraction task to interfere

The role of phonological loop in the probe digital task

Predictions:

• Slow presentation → more information decay

• Fast presentation → less time to rehearse but also less information decay

Is rehearsal useful in all tasks? Not necessarily

Probe-digit task

• Better recall in fast (when lots of interfering items) → rehearsal not quite useful in probe-digit task

Working memory - central executive

When do we use this? 

• Anything that needs attention!

Correlation between working memory capacity and attention control

• Larger working memory capacity → better control over attention

• Kane et al (2001): letter identification in prosaccade vs antisaccade condition

  • Procedure cue → target (letter) → identify

    • Prosaccade: cue and target on the same side of the display

    • Antisaccade: cue and target on the opposite side

  • Participants divided into two groups based on working memory capacity

Kane et al. (2001): Results

• Higher WM span leads to better attention control (faster resp. in antisaccade condition)

  • ”Attention” is NOT just about attention! WM is also an integral part of it.

Common working memory measures

• Digit Span

  • Forward

  • Backward

• Nonword span

  • Forward

  • Backward

• Complex span

• N-back

Working memory – Complex span

Complex span task

Instruction: read out aloud each sentence
and decide whether the sentence is true.
After a few trials, you will be asked to
recall the last word of each sentence in the
correct order.

Two components of complex span

• Word span

  • One sentence at a time

  • After a few sentences, Ss recall the last word of each sentence in correct order

• Comprehension

  • True/False judgment on each sentence

Complex span task (cont)

• Measures not only storage capacity but also storage quality (thru comprehension of materials)

• Reading sentences: central executive, phonological loop and visuo-spatial sketchpad

• If sentences are presented auditorily only: central executive and phonological loop

• Think about what factors experimenters should consider when designing a complex span task

Complex span task (cont 2)

Some factors to consider

• Sentence length

• Frequency of the last word

• Sentence structure

• Sentence meaning

• Length of the last word in each sentence

Another measure of WM: n-back

• Can be either auditory or visual

• Letter, number, or spatial location

  • Example: Auditory 2-back (press a button on the target)

Summary: Working memory: Processing input + temporary storage

• Not just about storage but also processing of input

• Interconnected components

  • Visual WM indirectly connects with phonological loop via central executive

  • Interaction with long-term memory

Attention and working memory interacts with each other

• WM also crucial in dichotic listening task and dual task

• WM capacity correlated with attention control

Working memory measures

• How do the complex span task and n-back task work?

• What do they measure?