Coding, Capacity, Duration Of Memory

Question 1

Baddeley (1966) - STM and LTM coding

Answer 1

Procedure -

Test recall of acoustically similar words e.g cat, car, cab and dissimilar words e.g. pit, few, one
Semantically similar words e.g big, large, huge, and semantically dissimilar words e.g. large, quiet

Findings/conclusions -

STM recall worse with acoustically similar words - suggests STM is acoustically coded

LTM recall (20 mins) worse with semantically similar words - suggests LTM is semantically coded

Question 2

Jacobs (1887) - STM capacity

Answer 2

Procedure-

Researcher reads 4 digits and increases the amount of digits until the pt cannot recall the order correctly

Findings/conclusions -

On average pts could recall 9.3 numbers and 7.3 letters

Question 3

Miller (1956) - STM capacity

Answer 3

Procedure -

Miller in his observations of everyday practice noted that things come frequently grouped in 7s. - 7 musical notes, 7 days, 7 wonders of the world, 7 deadly sins etc.

Findings/conclusions -

Span of STM is about 7 items (+/- 2) but can be improved by ‘chunking’ sets of digits/letters into meaningful units.

Question 4

Peterson+Peterson (1959) - STM duration

Answer 4

Procedure -

24 students had to remember a consonant syllable (e.g. YBN) and a 3 digit number to count backwards for 3, 6, 9, 12, 15, and 18 seconds.

Findings/conclusions-

80% recall of syllables with a 3-second interval. After 18 seconds - recall fell to 3%.
Suggests duration of STM with no rehearsal is about 18-30 s

Question 5

Bahrick et al (1975) - LTM duration

Answer 5

Procedure -

392 Americans ages 17-74.

1. Recognition test of 50 photos from pts’ high school yearbook.
2. Free recall test - pts listed names of their graduating class.

Findings -

Even pts tested 48 years after graduation had 70% recall accuracy. Free recall task was less accurate.