Short and long term memory

Question 1

STM (Short-Term Memory):
LTM (Long-Term Memory):

Answer 1

STM: Limited capacity and duration; stores information acoustically.
LTM: Unlimited capacity and duration; stores information semantically.

Question 2

STM Capacity

Answer 2

Assessed using digit span tasks (Joseph Jacobs, 1887). Average span: 9.3 for digits, 7.3 for letters.

George Miller (1956): “Magic Number 7 ± 2”. STM stores 7 items (±2). Chunking can help extend capacity.

Question 2

STM Duration:

Answer 2

Peterson and Peterson (1959): 24 students recalled trigrams after intervals (3–18 seconds) with distractor tasks.

Results: 90% correct after 3 seconds; 2% correct after 18 seconds.

STM duration = ~18 seconds.

Question 3

LTM Duration

Answer 3

Bahrick et al. (1975): 392 participants tested on memory of classmates’ names/faces after 15–48 years.

Results: ~60% accuracy for names/faces after 48 years.

Question 3

STM Coding

Answer 3

Primarily acoustic.

Baddeley (1966): Participants struggled to recall acoustically similar words (e.g., cat, cab).

Question 3

LTM Coding

Answer 3

Primarily semantic.

Baddeley (1966): Struggled with semantically similar words (e.g., large, big).

Question 3

Bahrick et al. (1975)

Answer 3

Tested real-life memory using high school yearbooks for LTM duration.

Question 3

Peterson and Peterson (1959)

Answer 3

Used controlled lab tasks to investigate STM duration.

Question 4

Baddeley (1966)

Answer 4

Experimental lab study investigated STM and LTM coding.