Coding, Capacity, Duration

• Coding- the format in which information is stored to the various memory stores. The process of converting information from one form to another.
• Baddeley investigated coding by giving word lists to participants to remember and recall in order.

  1. Acoustically similar
  2. Acoustically dissimilar
  3. Semantically similar
  4. Semantically dissimilar

  When recalling straight away, they did worse with acoustically similar words; when recalling after 20 minutes they did worse with semantically similar words. Shows different memory stores code information differently.
• Capacity- the amount of information that can be held in a memory store.
• Jacobs researched capacity by giving participants a list of numbers and increasing the length each time of recalled in the correct order. He also did this with letters.

  Mean digit span = 9.3

  Mean letter span = 7.3
• Miller reviewed short term memory research and suggested the capacity was 7 items (+ or - 2). He also put forward the idea that people can increase capacity by chunking together information.
• Duration- the length of time information can be held in memory.
• LTM research: Bahrick et al studied 392 participants aged 17-74. He tested their year book recall in 2 ways.

  1. Photo recognition
  2. Free recall test

  Participants tested within 15 years of graduation had 90% accuracy photo recognition and 60% free recall. Participants over this had 70% photo recognition and 30% free recall. Shows LTM duration is potentially a lifetime.
• STM research: Peterson and Peterson tested 24 undergraduates. They each took part in 8 trials. Each trial they were given a trigram (eg, YVC) to remember, then given a 3 digit number and asked to count backwards to prevent rehearsal. Each trial they were told to stop counting after 3,6,9,12 or 18 seconds. Results showed STM may have very short duration unless rehearsed for 18-30 seconds.
• H.M case study: He had anterograde (can’t form new memories) and retrograde amnesia (can recall old memories), and to control his seizures he had surgery to remove his hippocampus and amygdala. His seizures decreased, but he could no longer form new memories or remember the prior 11 years.
• STM for: coding- mainly acoustic, capacity- 7 plus or minus 2 items, duration- 18 to 30 seconds.
• LTM for: coding- mainly semantic, capacity- potentially unlimited, duration- potentially a lifetime.
• Evidence for more than 1 STM store: KF could recall digits if he read them but not if they were read to him.