Coding, capacity and duration of memory

• There are three main types of memory: sensory memory, short term memory, and long term memory.
• Sensory memory is where the information goes when it is immediately collected from the senses, such as what we have seen, heard, tasted, touched, or smelled.
• Iconic memory refers to visual stimuli, and echoic memory refers to auditory stimuli.
• Short term memory is our memory for immediate events.
• Long term memory is our memory for events that have happened in the past.
• Capacity in memory refers to how much can be held in the memory store.
• Duration in memory refers to how long the information can be held in the memory store.
• Peterson & Peterson (1959) studied the duration of Short Term Memory (STM) and found that without rehearsal, STM has a very short duration of around 18-30 seconds.
• Baddely used word lists of acoustically similar words and semantically similar words to test how acoustic and semantic coding effects the STM and LTM.
• Coding in memory is the way the information is processed in order for it to be stored.
• Information enters the brain via the senses and can then be stored in three different ways: visual (such as a picture), acoustic (such as sound), or semantic (meaning of experience).
• Two types of sensory memory is iconic and echoic memory.
• The duration of LTM is said to be unlimited.
• Sensory memory

  • duration: 0.25-0.5 seconds
  • capacity: very large
  • encoding: modality (sense) specific.
• Short-term memory

  • capacity: 5-9 items
  • duration: 18-30 seconds
  • coding: acoustic
• Long-term memory

  • capacity: unlimited
  • duration: lifetime
  • coding: semantic