Verbal working memory and the phonological buffer: The question of serial order

Area of Science:

• Cognitive Neuroscience
• Psychology

Background:

• The Working Memory model posits modality-specific buffers for temporary information storage.
• The phonological buffer traditionally assumes undifferentiated storage of item identity and serial order using phonological codes.

Purpose of the Study:

• To critically review the codes and processes underlying item and serial order maintenance in verbal working memory.
• To examine evidence for distinct neural substrates and representational mechanisms for item versus serial order information.

Main Methods:

• Review of neuroimaging studies examining neural correlates of information retention.
• Analysis of patient studies reporting selective impairments in item or serial order recall.
• Synthesis of findings on phonological processing and dorsal language pathways.

Main Results:

• Brain injury studies reveal selective deficits in short-term retention of item vs. serial order information.
• Neuroimaging data indicate distinct neural substrates for item and serial order retention.
• Evidence suggests separate representational mechanisms within phonological processing areas for item and serial order.

Conclusions:

• Verbal working memory likely employs multiple, simultaneous processes for serial order information, including domain-general and phonological mechanisms.
• Phonological serial order coding may involve the dorsal language pathway, but distinct coding processes for item and serial order are necessary.
• Current evidence supports a more nuanced view of the phonological buffer, differentiating item and serial order representation.