General knowledge

• What is the capacity, duration, encoding of Semantic Memory?


  Capacity: Very large (takes in everything from 5 senses)

  Duration: <2 seconds

  Encoding: Iconic, Echoic, Haptic
• What is capacity, duration, encoding of Short-term Memory?


  Capacity: 7+/-2 chunks

  Duration: 18-30 seconds

  Encoding: Acoustic
• What is capacity, duration, encoding of Long-term Memory?


  Capacity: No known limit

  Duration: Up to a lifetime

  Encoding: Semantic
• Model


  A simplified version of reality, often in the form of a diagram
• Memory


  A recollection of past events, new learnings, and emotions that can be stored for future use
• Encoding 


  How sensory input is represented by the memory system (What format is it in?)
• Capacity 


  How much information can be stored
• Duration


  How long the information can be held in storage
• What was Sperling (1960)'s experiment about?

  Sensory Memory

  • chart of letters
  • p's recalled 4-5 letters although aware of more letters
  • CONCLUSION: information decays quickly from the sensory memory (>2 seconds)
  • 3 stores (iconic, echoic, haptic)
• What was the experiment to test the capacity of STM?


  Digit span test by Jacobs (1887)

  • list of numbers to recall, longer each time
  • result: 6/7 numbers on average
• What did Miller (1956) propose about the capacity of STM?

  • 7 +/- 2 items, "magic number seven"
  • "chunking" information can increase memory span
• Maintenance Rehearsal


  Continuing repeating the information, this can potentially lead to transfer of information to LTM
• Elaborative Rehearsal 


  Making information meaningful to ensure it stays in the LTM
• What was the experiment about the duration of STM?

  Peterson & Peterson (1959)

  • consonant trigram, for example NGV
  • p's count backwards in 3 to prevent rehearsal
  • result: 80% recalled after 3 seconds, fewer than 10% recalled after 18 seconds
  • if rehearsal is prevented, information decays rapidly from STM
• What was the experiment about the duration of LTM?

  Barrack (1975) sampled 392 American ex high-school students aged between 17 and 74 with their yearbook photos

  • two groups- recognition/recall
  • results: after 47 years- recognition 60% accurate, recall less than 20% accurate
  • certain information can last a lifetime
• What are the two types of encoding?


  1. Acoustic - sounds
  2. Semantic - the meaning of the stimulus
• What was Conrad (1964)'s experiment about?

  Acoustic encoding

  • p's shown acoustically similar and dissimilar words for 0.75 s
  • result: errors were made when letters sounded alike even when visually presented
• What was Baddeley's experiment on Semantic Encoding?

  • 4 types of Word lists (Acoustically similar, Acoustically dissimilar, Semantically similar, Semantically dissimilar) tested after 20 minutes
  • result: recall was better for semantically dissimilar words
• Scientific evidence

  • Observable
  • Measurable
  • Replicable
• Acoustic confusion 


  Making erroring with acoustically similar letters
• Strengths of laboratory experiments

  • Same conditions so you are able to control variables
  • Allows repetition for a large sample size
• Limitations of laboratory experiments

  • Unlike real life scenarios
  • Ethical reasons: could cause stress to participants