Capacity

• Definition

  The amount of information that can be held in a memory store.
• Jacobs - procedure

  • Researcher reads out 4 digits + increases amount until participants can no longer correctly recall.
  • This is their digit span.
• Jacobs - findings

  Digit span

  • 9.3 numbers
  • 7.3 letters
• Jacobs - conclusion

  Miller - capacity of STM is 7 +/- 2 and chunking improves capacity.
• Strength - replication

  • Jacobs' study has been replicated and confirmed by other, better controlled studies since.
  • Suggests that Jacobs' study is a valid test of digit span.
• Limitation - chunk amount

  • Miller may have overestimated STM capacity.
  • Cowan reviewed other research and concluded that the capacity of the STM is only about 4 chunks.