Research on Duration.

What did Margaret and Lloyd Peterson, 1959, do for STM?

Tested 24 undergraduates

What did each student have to do?

Take part in 8 trials.

What happened on each trial?

The student was given a consonant syllable to remember and a 3 digit number.

What's the 3-digit number used for?

The student was asked to count backwards from that 3-digit number until told to stop.

Why did the students have to count backwards from their 3-digit number?

To prevent any mental rehearsal of the constant syllable

What is the retention interval?

On each trial they were told to stop after a different amount of time

What do the Peterson & Peterson trial suggest?

STM may have a very short duration unless we repeat something over and over again.

What did Harry bahrick and colleagues, 1975, do for LTM?

Studied 392 participants from the American state of Ohio who were aged between 17 and 74.

Name 1 way recall was tested:

Photo-recognition test consisting of 50 photos, some from the participant's high school yearbook

Name another way recall was tested:

Free recall test where participants recalled all the names of their graduating class.

How accurate were participants within 15yrs of graduation for photo recognition?

About 90% accurate

How accurate were participants after 48 yrs of graduation for photo recognition?

Recall declined to about 70%

How accurate were participants within 15yrs of graduation for free recall?

About 60% accurate

How accurate were participants after 48 yrs of graduation for free recall?

Dropped to 30%

What do the accuracies for photo recognition and free recall show?

LTM can last a very long time.