Capacity

• What is capacity?

  How much information can be held in memory stores at any one time.
• what did jacobs 1887 do and find?

  • digit span test for capacity of STM.
  • 9.3 for digits.
  • 7.3 for letters.
  • because there are less number than letters which makes it less difficult to remember.
• what did miller 1956 do and find?

  • found that people could absorb 7 new pieces of information in STM at a time.
  • magical umber 7+/-2
  • people can remember 5 words like 5 letters.
  • suggested chunking
• what is chunking?

  the process of grouping sets of digits or letters into meaningful units that would make them easier to remember.
• what is the capacity of LTM?

  unlimited
• evaluate replication of jacobs’ study?

  • older studies may lack control.
  • jacobs’ findings have been confirmed by more controlled studies.
  • jacobs study is a valid test of digit span
• evaluate miller may have overestimated?

  • Cowan reviewed research and found capacity of STM is only about 4+/-1
  • Vogel et al conducted research into capacity of stm- 4 chunks is the limit.
  • millers estimate of 5 items is more appropriate than 7