Duration

Question 1

Duration

Answer 1

length of time information can be held in the memory

Question 2

Duration of STM

Answer 2

Peterson and Peterson (1959) used 24 students who took part in 8 trials. Each trial given a trigram (3 letters) to remember and a 3 digit number. Asked to count backwards from 3 digit number until stopped. (prevent maintenance rehearsal). Stopped after 3,6,9,12,15,18 = retention interval. STM short as most remembered after 3 secs but 3% after 18 secs, suggests 18 secs = duration.

Question 3

Weakness of STM

Answer 3

Artificial stimulus.
Used a trigram.
Meaningless to them so don’t know duration of meaningful meaning lacks mundane realism, and ecological validity so generalisable.
However, phone numbers/post codes have meaning even though just digits, giving more validity.
Cannot assume duration of STM 18 secs for meaningful, but shouldn’t be dismissed until further research done.

Question 4

Duration of LTM

Answer 4

Bahrick et al (1975) studied 392 pps. Did photo recognition test consisting of 50 photos from high school yearbook and free recall test of all names in graduating class. Tested within 15yrs of graduation 90% accurate in photo recognition test (acts as trigger), after 48yrs recall decline to 70%. 15yrs at 60% accuracy for free recall test, 48yrs at 30% accuracy.

Question 5

Strength of LTM

Answer 5

High external validity.
Used high school yearbook photo and names of graduating class (meaningful).
Gives ecological validity so generalisable to everyday life.
Furthermore, Shepard (1967) used meaningless pictures found recall rate was lower, suggest meaningful stay longer.
Used to identify duration of meaningful information in LTM as more representative.