Coding, Capacity, Duration

Question 1

Encoding

Answer 1

• Info arrives in sensory memory as a sound, image or feeling.
• 3 main ways of coding:
  —> acoustic coding : sound of a stimulus
  —> visual coding : physical appearance of a simulus.
  —> semantic cod : meaning of the stimulus.
• STM uses acoustic coding / LTM uses semantic coding.

Question 2

Coding - Baddeley (Acoustic & Semantic)

Answer 2

Procedure:
- 4 Groups given either:
- Acoustically similar words (e.g. cat, cab, can) or dissimilar (e.g. pit, few, cow).
- Semantically similar (e.g. great, large, big) or dissimilar (e.g. good, huge, hot).
- Pps asked to recall in order.

Findings:
- Immediate recall worse with acoustically similar words, STM is acoustic.
- Recall after 20 mins worse with semantically similar words, LTM is semantic.

Question 3

Limitation of Baddeley

Answer 3

ARTIFICIAL STIMULI / LIMITED APPLICATION

1) The words used had no personal meaning to the pps so tells us little about coding for everyday memory tasks.
2) When processing more meaningful info, ppl use semantic coding even for SIM.
—> This means the findings of this study have limited application.

Question 4

STM / LTM - Capacity

Answer 4

LTM —> limitless , losses happen through decay & interference not a limit on capacity
STM —> limited capacity, can only hold a small amount of info before forgotten.

—> test STM capacity using a serial digit span study.

Question 5

Factors Influencing STM Capacity

Answer 5

1) Chunking - grouping info may help improve capacity.
2) Age - at 2 yrs (2 digits) , 5-6 yrs (4 digits) , 9 years (7 dig) —> digit span increases with age.

Question 6

STM - Duration

Answer 6

• STM doesn’t last very long
• Rehearsal keeps memory active.
• Verbal rehearsal allows the memory to become long-term.
• If too much info stored in STM then displacement happens:
  —> Means 1st piece of info is first to be replaced when max capacity happens.
  —> If we don’t fill up our STM & we rehearse info then its moved into LTM.

Question 7

Capacity - (Digit Span)

Answer 7

Jacobs (1887)
Procedure:
- Researcher reads 4 digits & increases until the pp cannot recall the order correctly.
- Final number = digit span.

Findings:
- On average, pps could repeat back 9.3 numbers and 7.3 letters in the correct order immediately after they were presented.

Question 8

Strength of Jacobs

Answer 8

STUDY HAS BEEN REPLICATED

1) This is an old study and may have lacked adequate controls (confounding variables e.g. pps being distracted).
2) Despite this, Jacobs’ findings have been confirmed in later controlled studies (e.g.
Bopp and Verhaeghen
2005).
—> This shows that Jacobs’ study is a valid measure of STM digit span.

Question 9

Capacity - Magic Number

Answer 9

Miller (1956)
Procedure:
- Miller observed everyday practice, noted that things come in sevens - days of the week, deadly sins, etc.

Findings:
- Span of STM is about 7 items (plus or minus 2) but is increased by chunking - grouping sets of digits/letters into meaningful units.

Question 10

Limitation of Miller

Answer 10

MAY OVERESTIMATE STM CAPACITY

1) Cowan (2001) reviewed other research - He concluded that the capacity of STM was only about a plus or minus 1) chunks.
—> This suggests that the lower end of Miller’s estimate (5 items) is more appropriate than
7 items.

Question 11

Duration STM - Consonant Syllables

Answer 11

Peterson and Peterson (1959)

Procedure:
- 24 students given a consonant syllable (e.g. YCG) to recall and a 3-digit number to count backwards from. The retention interval was varied: 3, 6, 9, 12, 15, 18 secs.

Findings:
- After 3 secs - average recall was about 80%. After 18 secs it was about 3%.
–> STM duration without rehearsal is up to 18 secs. Supports STM & LTM are separate.

Question 12

Limitation of Peterson and Peterson

Answer 12

LACKS ECOLOGICAL VALIDITY

1) We sometimes try to recall meaningless things so the study is not completely irrelevant - BUT recall of consonant syllables doesn’t reflect meaningful everyday memory tasks.
—> Therefore the study lacked external validity.

NOT REPRESENTATIVE SAMPLE

1) Students may be more used to rehearsal.

Question 13

Duration LTM - Yearbooks

Answer 13

Bahrick et al. (1975)

Procedure:
- Pps were 392 Americans aged between 17 - 74.
1. Recognition test - 50 photos from high school yearbooks.
2. Free recall test - Pps listed names of their graduating class.

Findings:
- Recognition test - 90% accurate after 15 years, 70% after 48 years.
- Free recall test - 60% recall after 15 years, 30% after 48 years.

Question 14

Strength of Bahrick et al.

Answer 14

HIGH ECOLOGICAL VALIDITY

1) Everyday meaningful memories (e.g. of people’s faces and names)
were studied.
2) When lab studies were done with meaningless pictures to be remembered, recall rates were lower (e.g. Shepard 1967).
—> This means findings reflect a more ‘real’ estimate of the duration of LTM.