M: Lesson 2: Capacity, Duration and Coding Flashcards
Coding in the SR?
Coding is modality specific meaning each sensory store codes information differently e.g iconic for visual information
Coding in the STM?
Baddeley (1966) investigated coding in STM by giving participants 4 lists of words to recall. List A was made up of words that sounded similar and list B contained words that sounded dissimilar. List C had words with similar meanings, and list D contained words with dissimilar meanings. From this, Baddeley argued that STM is coded acoustically as participants performed worse with list A than list B, but there was no difference between C and D. Therefore, he argued that STM organises information according to how it sounds, and similar sounding words can become muddled.
Coding in the LTM?
Baddeley repeated his experiment to test coding in LTM. He tested recall after 20 Minutes to ensure information had moved into LTM. This time, there was no difference between list A and B, but participants recall of C was worse than D. He concluded that LTM was coded semantically. LTM organises information according to its meaning so words with similar meaning can become confused.
Coding in the LTM?
Baddeley repeated his experiment to test coding in LTM. He tested recall after 20 Minutes to ensure information had moved into LTM. This time, there was no difference between list A and B, but participants recall of C was worse than D. He concluded that LTM was coded semantically. LTM organises information according to its meaning so words with similar meaning can become confused.
Evaluation of Baddley’s Coding Experiments
+ This study is a lab experiment and reliability is high meaning it can easily be replicated.
- The experiment has low ecological validity, as the list of words participants needed to recall was artificial as was the lab setting.
Capacity of SR?
Unlimited
Capacity of STM?
Jacobs used a digit span test to determine STM capacity. He gave participants increasingly long sequences of digits and numbers, and told them to repeat it immediately after he had given it, in the correct order. He found that on average we can hold 9.3 digits and 7.3 letters. When Miller reviewed this, he found that the span of STM is 7 (+/- 2). If we try and recall new information, this new information displaces the old information. He also found that chunking can help us remember more, as we can also remember 5 words and 5 letters.
Capacity of LTM?
Unlimited
Evaluation of Jacobs Capacity Experiment
+ Jacobs research was first to acknowledge that STM capacity gradually improves with age.
- This study was conducted a long time ago, so may not have been done to the same scientifically rigorous standard as research today, and therefore the validity can be questioned.
Duration of SR?
250 Milliseconds
Duration of STM?
Peterson & Peterson used nonsense trigrams to test STM duration. To prevent maintenance rehearsal they were asked to count backwards from 100 in threes. After 3 seconds, recall was accurate 90% of the time. After 9 seconds, recall was accurate 20% of the time but after 18 seconds, it was only accurate 2% of the time. They concluded information in STM lasts for 18-30 seconds before it decays into nothing
Duration of LTM?
Bahrick tested 400 people of various ages on their memory of their classmates. This included a photo recognition test, in which participants were shown 50 photos and had to decide whether they were in their class or not. They found 90% accuracy within 15 years of leaving school, and 70% accuracy after 48 years of leaving school. Free recall of names of classmates was 60% accurate within 15 years, and dropping to 30% after 48 years of leaving. He concluded that duration of LTM is potentially a lifetime, but sometimes we have retrieval failure and need retrieval cues in order to access this information.
Evaluation of Peterson&Peterson Duration STM test?
+The research is said to have high control, using standardised procedures to make sure all participants experienced the same process. This included fixed timings, eliminating noise etc.
- The findings may have been caused by interference rather than STM having short duration. It is possible that earlier learn trigrams became confused with later ones.
Evaluation of Bahrick LTM Duration Experiment?
+ High ecological validity as material was more meaningful and relevant to everyday life
- It’s problematic to control extraneous variables such as people staying in touch after they left school or how many participants looked in their yearbook since leaving school.
