Research on duration

• Duration of STM – Peterson and Peterson


  The duration of STM is investigated by Peterson and Peterson Were Participants were asked to recall trigrams after varying intervals of time where participants were asked to count backwards in threes to prevent rehearsal. He found that Recall accuracy decreased as the retention interval increased. After 18 seconds participants could hardly recall the trigrams.
• He concluded that without rehearsal, information in STM decays rapidly typically within 18-30 seconds . This suggests that the duration of memory is very short in the STM unless the information is actively rehearsed or transferred to LTM
• Duration of LTM- Bahrick et al 


  Bahrick et al investigated the duration of LTM by testing participants aged 17 to 74 ability to recall information from their high school years The participants were tested on there memory of recall of there high school classmates recall was tested using Free recall- listing names of class mates without any cues Photo recognition - Identifying class mates from a set of photos Name recognition – matching names to photos Picture matching – matching classmates names to photos
• • He found 90% accuracy within participants who graduated in the past 15 years in identifying names and faces. • After 48 years, accuracy for name recognition declined to about 80%, and for photo recognition to about 70%. • Free recall was less accurate than recognition tasks, dropping to 30% accuracy after 48 years.
• Bahrick et al. concluded that LTM can retain information for a very long time, particularly when the information is meaningful and well-rehearsed (e.g., names and faces of classmates).However, memory recall becomes less accurate over time, especially for tasks requiring free recall.
• High ecological validity: The study used real-life memories, making it more generalizable.
• Large sample size: Enhanced reliability of the findings.
• Lack of control over confounding variables: Some participants may have had more opportunities to rehearse the information (e.g., keeping in touch with classmates). Recognition tasks may not fully reflect LTM’s limitations, as cues help jog memory.
• Duration of stm evaluation

  A limitation of Peterson and Peterson's research into duration of STM is that the material used in the study is artificial which can be criticized for not having any real life meaning or value to the participants as recalling consonants and syllables does not accurately reflect everyday memory activities where what we are trying to remember is meaningful therefore the study lacks external validity
• Stimuli from the environment eg sound passes into the sensory register from our senses
• Coding -SR

  Memory is coded modality specific depending on our senses eg coding for visual information is iconic memory

  Store coding acoustically (sound) is echoic memory
• Duration - SR

  Material in sensory register is very brief , less than half a second information passes further into the memory system only if you pay attention to it