short term memory

What is short-term memory (STM)?

A temporary store where information is coded mainly acoustically and lasts about 18-30 seconds unless rehearsed.

What is the duration of STM?

18-30 seconds.

What is the capacity of STM?

7 +/- 2 items (average of 5 to 9 items).

How is information mainly coded in STM?

Acoustically (by sound).

What happens if STM information is not rehearsed?

It is forgotten or displaced after about 30 seconds.

What is maintenance rehearsal in STM?

Repeating material to ourselves over and over to keep it in STM.

What happens if STM information is rehearsed long enough?

It passes into long-term memory (LTM).

How can STM capacity be increased?

Through chunking (grouping items into larger units).

What is an example of chunking in STM?

Converting a phone number like 01494324654 into chunks: 01494, 324, 654.

What happens to ignored sensory information?

It does not move from the sensory register to STM.

How can information be encoded in STM?

Visually (as an image), acoustically (as a sound), or semantically (through meaning, less often).

What does Cowan’s research suggest about STM capacity?

It might be closer to 5 items rather than 9.

What is the key study for STM duration?

Peterson & Peterson (1959).

What was the setup of Peterson & Peterson’s (1959) study?

Participants were given trigrams (e.g., TYF, GHW) to recall after 0-18 seconds, with an interference task to prevent rehearsal.

What was the interference task in Peterson & Peterson’s study?

Counting down from a number (e.g., 56: 55, 54, 53, 52) until told to stop.

What were the results of Peterson & Peterson’s study?

Only 10% of trigrams were recalled after 18 seconds.

What did Peterson & Peterson conclude about STM?

STM duration is about 18 seconds, indicating memories are short-lived.

What is the key study for STM capacity?

Jacobs (1887).

What was the setup of Jacobs’ (1887) study?

443 female students (aged 8-19) recalled strings of numbers or letters in order; digits/letters increased until recall failed.

What were the results of Jacobs’ study?

Participants recalled 9 numbers on average but only 7 letters.

What did Jacobs conclude about STM capacity?

STM capacity is 7 +/- 2 items (5 to 9), and recall improves with age.

What did Miller (1956) theorize about STM capacity?

Capacity is about 7 items, influenced by patterns like 7 days of the week, and can be extended by chunking.

What is an example from Miller’s theory?

You can recall 5 words as easily as 5 letters by chunking information.

What is the key study for STM coding?

Baddeley (1966).

What was the setup of Baddeley’s (1966) STM study?

Participants recalled four sets of words immediately: similar sounds (e.g., cat, mat), different sounds (e.g., dog, bin), similar meaning (e.g., big, large), different meaning (e.g., huge, good).

What were the results of Baddeley’s STM study?

More mistakes were made recalling similar-sounding words (e.g., cat and cap confused).

What did Baddeley conclude about STM coding?

STM codes information acoustically, as similar-sounding words get confused during recall.