Working Memory Notes

What is Working Memory?

  • Baddeley and Hitch (1974): Limited capacity system for temporary storage and manipulation of information for complex tasks.
  • Active process requiring mental resources.
  • 3-part system: phonological loop, visuospatial sketch pad, and central executive.

Capacity of Working Memory

  • Luck and Vogel (1997), Cowan (2001): Capacity is approximately 4 items, determined via change detection task.
  • Alvarez & Cavanagh (2004): Challenged findings using colored squares and complex objects.

Components of Working Memory

  • Phonological Loop: Holds verbal and auditory information.
    • Phonological similarity effect: Similar-sounding letters/words are confused.
    • Word-length effect: Short words are easier to remember than long words.
    • Articulatory suppression: Repeating a word prevents rehearsal, reduces memory span.
  • Visuospatial Sketch Pad: Holds visual and spatial information.
    • Visual imagery: Creating images in the mind without a physical stimulus.
    • Shepard and Metzler (1971): Mental rotation task; longer rotations take more time.
  • Central Executive: Pulls information from long-term memory, coordinates phonological loop and visuospatial sketch pad.
    • Attention controller: Focuses, divides, and switches attention; suppresses irrelevant information.
  • Episodic Buffer: (Added in 2000)
    • Limited-capacity temporary storage integrating information from various sources.
    • Holds information longer and has greater capacity than the phonological loop or visuospatial sketch pad.
    • Backup store communicating with long-term memory and working memory components; controlled by the central executive.

Short-Term Memory vs. Working Memory

  • Short-Term Memory: Passive storage system, unitary store, emphasis on memory.
  • Working Memory: Active system for storage, processing, and manipulation of information, multi-component, emphasis on complex cognition.

Working Memory and the Brain

  • Prefrontal cortex (PFC) processes incoming visual and auditory information.
  • Funahashi et al. (1989): Neurons in monkey PFC respond to stimulus location and during delay.
  • Stokes (2015): Information stored in short-term changes in neural networks.
    • Activity-silent working memory: Information causes neurons to fire (activity state), then connections strengthen (synaptic state).