Working Memory Model

• Baddeley + Hitch (1974) criticised MSM for being simplistic and proposed a processing model of STM that suggests STM has multiple stores/components
• Central executive


  • monitors incoming data, directs attention and allocates tasks to the 3 slave systems
  • flexible coding- doesnt have fixed coding system
  • very limited capacity
• Phonological loop (PL)


  • deals with verbal and auditory info
  • Phonological store: stores words you hear
  • Articulatory process: allows for maintenance rehearsal of verbal info to keep it in the working memory
  • acoustically coded
  • about 2 sec capacity
• Visuo-spatial sketchpad (VSS)


  • stores visual and spatial info
  • Logie (1995) subdivided into: Visual cache- stores visual data + inner scribe- records arrangement of objects in visual field
  • coding is visual+spatial
  • limited capacity of 3-4 objects
• episodic buffer (EB)


  • Baddeley (2000)
  • temporary store for info
  • integrates visual, spatial + verbal info from other stores and maintains a sense of time sequencing (data reflects order in which events occur)
  • links to LTM
  • flexible coding
  • capacity of about 4 chunks of info
• strength/CA- supporting evidence (KF)


  • KF had a motorcycle accident and suffered brain damage causing him amnesia
  • he could effectively process visual info normally but his STM struggled with auditory info
  • supports existence for separate stores for verbal and visual information- PL+VSS
  • however, this case study is based on 1 unique individual who had brain injury, it is unsure if KF had other potential brain impairments prior to his accident which affected his memory performance
  • limits generalisability
• strength- empirical support for PL (baddeley+Hitch 1975)


  • found that pps could recall lists of short words more easily than long words- called this the word-length effect
  • supports existence of PL as suggests it has a time based capacity- shorter words take less time to rehearse allowing more items to be retained
  • alligns with WMM concept that STM not unitary+ strengthens validity
• strength- supporting evidence for VSS (baddeley et al 1975)


  • pps found it harder to carry out 2 visual tasks at the same time than do a verbal and visual task together (same for 2 verbal tasks)
  • this due to both visual tasks compete for the same slave system- VSS
  • no competition with a verbal and visual task
  • implies must be a separate store that processes visual data (VSS) and a separate store for verbal data (PL)
• Limitation- lack of clarity over CE (baddeley 2003)


  • Baddeley (2003) said that CE was most important system but the least understood component of working memory
  • if its most important then their must be more to it than just directing attention e.g does it have subcomponents
  • shows that theory doesnt accurately explain aspects of working memory+ further research needed for it to be a valid model