Short Term Memory and Research

• What is cognitive?

  A mental process involved in gaining knowledge and comprehension
• What is cognitive Psychology about?

  The study of mental processes including language use, problem solving and memory
• What is memory?

  The process of by which we retain information about things/events that have happened in the past
• What is Short Term Memory?

  Information from the present or immediate past.
• What is a duration?

  The amount of time that information can stay in the memory before it is no longer available
• What is capacity?

  How much information can be held in the memory at one time.
• What is encoding?

  Encoding is the process of converting information into a specific format so that it can be stored in memory
• Duration of STM

  18 seconds
• Who did research into duration of STM

  Peterson and Peterson 1959
• Procedure of Peterson and Peterson's study

  • Ppnts briefly showed nonsense trigram (3 random letters).
  • Count backwards from 3s from specified number to prevent memorisation.
  • After intervals of 3,6,9,12,15,18 seconds participants were asked to stop
• Findings from the Peterson and Peterson study

  • after 3 seconds, participants recall was 85%
  • Longer intervals = few trigrams recalled.
  • After 18 seconds, less than 10% of trigrams were recalled correctly.
• Conclusion of Peterson and Peterson Research

  Information can be held in the STM without rehearsal for about 18 seconds.
• Good Evaluation Points of Peterson and Peterson Study

  Research was conducted in a laboratory so variables were well controlled and cause and effect could be established. Also, since it was done in a laboratory, this means the findings can be relied on. and this also increases the validity of the study.

  • As the study was done in a lab, this means that the exact procedure can be replicated by other researchers further highlighting the reliability.
• Weakness Evaluation of Peterson and Peterson

  1. Marsh et al 1997 criticised findings of P&P because the participants were aware that they were being tested on the trigrams (Hawthorne effect).
  2. When they conducted their own studies, they found that forgetting happened after 2 seconds.

  • This suggests that duration may be lower than 18 seconds
• Weakness Evaluation of P&p

  Nairne 1999 conducted a study into STM duration and found that in some recall cases, recall was possible after 96 seconds.

  • This contradicts the findings of P&P. However, as 3 psychologist have found 3 varying degrees of what the duration of STM could be, it may be that our knowledge of the STM is not as clear cut as many psychologist think.
  • Contradictory findings lower the reliability of findings
• Weakness Evaluation of P&P

  Lack of Ecological Validity

  - The methods that were used in research do no reflect a real-world setting and as such the results do not reflect what would happen in the real world scenario.

  • The lab environment was artificial and the trigrams are not meaningful to participants and this could have affected them in remembering as they would have thought it was useless to remember.
• How is information encoded in the STM

  Acoustically
• Who did the Research for encoding in the STM

  Conrad
• What was the Aim of Conrad's study

  To find out the way in which information encoded in the short-term memory
• What is the Procedure of Conrad's study?

  Participants were presented with 2 strings of letters, one was acoustically similar and the other one was acoustically dissimilar.
• Findings of Conrad's study

  1. More mistakes when recalling strings with similar sounds. (Acoustically similar)
• Conclusion of Conrad from Study

  The sound of the letters mattered in econding in the STM.

  Even when presented visually, the information must have been changed into sound on the way to ps memory.

  Due to the errors that happened, he concluded that information was encoded acoustically in the STM
• What is the capacity of the STM

  7+/-2
• Who did research into capacity of STM

  Miller 1956