Working memory studies

Salmon (1996)

  • Aim: Replicate previous findings concerning brain areas activated by a verbal working memory task

  • Showing several stores of memory


  • 10 Male, European, Right-Handed Volunteers (19-30)

  • Scans were taken using PET Scanner


  • Visual STM Task - 6 Korean Letters were randomly displayed - PPS had to tap Yes or No to whether any of the Korean letters they saw appeared again -> Can't be transcoded into phonological loop)

  • Phonological STM Task - 6 sequences of phonologically dissimilar consonants were displayed - PPS rehearsed this silently - PPS had to detect whether consonant was present in list

  • In each task, the Y/N Task happened 2 seconds after each sequence was displayed

  • Results

    • Phonological Loop - Lower Left Supramarginal Gyrus associated with STM Verbal Memory

    • Visuo-spatial sketchpad - Superior Occipital Gyrus associated with Visual STM


Why It Supports WMM

  • Different parts of the brain had more activity depending on whether they were encoded visually or verbally, proving that the WMM is right - there are multiple stores. 

  • It supports the phonological loop and visuo-spatial sketchpad.


Strength

Weakness

Controls - Timing - Ensured it was STM and not LTM


Objective Data - No researcher Bias

Brain Scan - No Demand Characteristics

  • No Social Desirability


High Internal Validity - Due to Control

Low Population Density

  • Low Representability


Not Testable - Expensive - Low 


Repeatability - Harder to check Reliability


Low Mundane Realism

  • BUT you rarely only need to use one (phono, visual) in a task


Low Ecological Validity - People act differently, uncomfortable during PET Scan - It's weird


Hitch and Baddeley

  • Aim: To Demonstrate different functions of working memory

  • Show that STM has limited processing capacity


  • 92 University Students 

  • PPS took sentence verification task - in 4 groups -> "A follows B, AB" True/False

  • Control Group - PPS did task without saying anything

  • Group 2 (one word) - Repeated the word 'the'

  • Group 3 (counting) - Repeated familiar counting sequence 1-2-3-4-5-6

  • Group 4 (digit-span) - Repeated 6 random digits


  • Groups 2 - 4 were doing Articulatory Suppression Tasks - G4 had complex sequence -> greater STM storage demands

  • Results

    • Frequency of errors didn't change, but solution times were affected

    • Group 4 took significantly longer

Conclusion + How it Supports WMM

  • PPS struggled to do two tasks together that required high use of CE

  • PPS were able to do two tasks using 2 separate stores easily

  • Provides evidence for:

    • Multiple STM Components

    • Components of STM have limited storage capacity

Strength

Weakness

Reliability

  • ↑ Repeatability - Testable


↑ Internal Validity - Due to Controls


Objective Data - No Researcher Bias


Independent Groups Design - No Order Effects

Low Mundane Realism

  • Strange, Weird Task


Low Representability


Independent Group Designs