Characteristics of memory

• What is memory?

  The process of storing information learnt from experiences such that it can be reproduced, recognised or recalled later.
• What is encoding?

  The form that a memory takes when we store it. Psychologists think that we encode memory based on:

  Visual encoding - how it looks

  Acoustic encoding - what the word for it sounds like

  Semantic encoding - the way we understand it
• What is capacity?

  The amount of information that can be held by a memory store. Depending on the memory store, capacity can be limited or unlimited.
• What is duration?


  The length of time for which memory lasts. Can range from less than a second or up to a lifetime.
• What links capacity and short-term memory?

  Capacity for STM is said to be 7 things +/- 2. (stated by Miller). The capacity of STM can be increased with chunking (grouping information together based on a shared meaning).
• What links capacity and long term memory?

  Capacity of LTM is said to be unlimited. Inability to access LTM's could result from a lack of availability (info no longer in LTM) or a lack of accessibility (difficulty 'finding' info in LTM).
• What links encoding and short term memory?

  Thought to be mainly acoustic.
• What links encoding and long term memory?

  Thought to be predominately semantic.
• What links duration and short term memory?

  It is said to last between 18-30 seconds.
• What links duration and long term memory?

  Duration is potentially life long.
• What did Baddeley investigate?

  The nature of encoding in STM and LTM.
• What did Baddeley do?

  He gave undergraduate participants 4 lists to learn:

  List 1 - acoustically similar

  List 2 - acoustically dissimilar

  List 3 - Semantically similar

  List 4 - semantically dissimilar

  Participants were tested immediately (STM) and again after 20 minutes (LTM) to see if they could remember the words in order.
• What were the findings of Baddeley's investigation?

  In the immediate recall section, recall of acoustically similar words was poorer than for acoustically dissimilar words. In the LTM section, recall for semantically similar words was poorer than for semantically dissimilar words.
• What was the conclusion of Baddeley's investigation?

  In STM, encoding is acoustic (as errors were based on sound) and in LTM encoding is semantic (as errors were based on meaning).
• What are evaluation points for Baddeley's investigation?

  • Remembering lists of words is not how we end to use our memories in everyday life, so findings about coding in STM/LTM may lack ecological validity
  • Baddeley conducted a laboratory experiment and adopted a standardised procedure (e.g. participants were given same lists to learn). Study could be repeated by others to check for reliability.
• What did Peterson and Peterson investigate?

  The duration of short term memory.
• How did Peterson & Peterson investigate the duration of STM?

  A lab experiment involved 24 participants. They had to recall trigrams (meaningless 3 consonant syllables). To prevent rehearsal participants were asked to count backwards in three's from a specified random number for differing periods of time (either 3, 6, 9, 12, 15, or 18 seconds).
• What were the findings of Peterson & Peterson's investigation?

  The longer the interval delay the fewer the trigrams correctly recalled. Participants were able to recall 80% of trigrams after a 3 second delay. However, after 18 seconds less than 10% of trigrams were recalled correctly.
• What was the conclusion of the Peterson & Peterson experiment?

  When rehearsal is prevented, over 90% of memories are lost by 18 seconds.
• What are the evaluation points for the Peterson & Peterson investigation?

  • All participants were psychology students. Similar group of people so lacks representation and hence generalisability.
  • Low ecological validity as carried out in a lab and not an everyday activity.
  • Standardised procedure - same trigrams were used for all participants. Therefore can be replicated and tested for reliability.
• What did Bahrick et al investigate?

  The duration of long term memory.
• How did Bahrick et al investigate duration in LTM?

  400 people aged 17-74 were used in the study. The tasks participants undertook focused on remembering their high school class. A number of different tests were used, including free recall for their classmates names, a photograph recognition test and a name recognition test.
• What were the findings of the Bahrick et al investigation?

  Participants performed less well on free recall tasks. After 15 years recall was 60% accurate and after48 years it was 30% accurate. In the verbal and visual recognition tasks accuracy after 15 years was 90% and after 48 years these had dropped to 80% and 70%.
• What was the conclusion of the Bahrick et al investigation?

  That ex-classmates are remembered very well after long periods of time and cued (recognition) recall is better than free recall.
• What are the evaluation points of the Bahrick et al investigation?

  • Large sample so wide range of ages, therefore high populational validity
  • Stimulus material was the year book, which is a commonplace item in the US, therefore has high ecological validity
  • Couldn't control whether participants looked at their year book regularly or met up with their ex-classmates, therefore low reliability
• What does iconic mean?


  The store of memory by vision - you can picture an object in your mind.
• What does echoic mean?


  The store of memory by sound - you can hear something in your mind.
• What did Murdock investigate?

  the effect of the position of a word in a list upon its recall.
• What did Murdock do?

  He got participants to read a list of words. They then had to recall the words. Murdock plotted the position of the words in the list compared to how often it was recalled.
• What were Murdock's findings?

  The words people recalled first were often the last ones in the list. The words at the start were also recalled well. Words in the middle were recalled poorly.
• What was the conclusion of Murdock's research?

  The last words in the list are still in STM so are recalled well. The words from the start are rehearsed and get transferred to LTM. There is too little capacity in STM to rehearse the words in the middle of the list.