memory - coding, capacity, duration

Question 1

describe the research into coding of LTM and STM

Answer 1

Baddeley (1966) gave different word lists to four groups of participants. Some were acoustically similar, acoustically dissimilar, semantically similar, semantically dissimilar. When recall was immediate (testing STM), participants tended to do worse with acoustically similar words so STM is acoustically coded. When recall was tested after 20 mins (testing LTM), participants tended to do worse with semantically similar words so LTM is semantically coded

Question 2

describe research into capacity of LTM and STM

Answer 2

Miller(1956) made observations and noted things came in groups of 7, so he assumed capacity of STM is 7+-2 items. He also noted that people can recall 5 words as easily as 5 words so we recall in groups, this is called chunking

Question 3

Describe research into duration of STM

Answer 3

Peterson and Peterson (1959) tested 24 students. They gave students consonant syllables and gave them a filler task of counting backwards to prevent mental rehearsal. They were told to recall the syllables after varying periods of time, differing with 3 seconds each time. After 3s, average recall was 80% and after 18s, average recall was 3% which shows duration of STM is 18s

Question 4

describe research into duration of LTM

Answer 4

Bahrick (1975) studied 392 participants aged between 17 and 74. Recall was tested using free recall or photo recognition. Participants tested with free recall had 30% correct recall after 48 years, participants tested with photo recognition had 70% correct recall after 48 years

Question 5

Discuss separate memory stores as a strength of research into coding of LT and ST memory

Answer 5

Theres a clear difference between two memory stores. The idea that STM uses mostly acoustic coding and LTM uses mostly semantic coding has stood the test of time. This is an important step in our understanding of the memory system

Question 6

Discuss artificial stimuli as a limitation of research into coding

Answer 6

Baddeley’s research used quite artificial stimuli rather than meaningful information. This is clear as the word lists had no personal meaning. This means the findings from the study have limited application

Question 7

Discuss validity as a strength of research into capacity

Answer 7

Jacob’s study has been replicated. Some participants digit spans might have been underestimated because they were distracted by extraneous variables. Despite this, Jacobs findings have been confirmed by other and better controlled studies, so it is a valid test of digit span in STM

Question 8

discuss overestimation of STM capacity as a limitation of research on capacity

Answer 8

Miller’s number may be an overestimate for STM. This is clear as Cowan (2001) reviewed other research and concluded that the capacity of STM is 4 +- 1. This suggests Millers lower estimate may be more accurate

Question 9

Discuss meaningless stimuli as a limitation of duration into STM

Answer 9

Peterson and Peterson used artificial material. The study is not completely irrelevant because we sometimes do have to recall meaningless material. Even so, recalling consonant syllables does not reflect everyday activities. This means the study lacks ecological validity

Question 10

Discuss high external validity as a strength of research into duration of LTM

Answer 10

Bahrick’s study has high external validity. The researchers investigated meaningful memories, as it used people’s names and faces. This suggests Bahrick’s findings reflect a more real estimate of duration of LTM