Duration

Duration refers to how long a memory ‘trace’ (i.e. information about the past) can be held for, before it is forgotten.

According to Atkinson and Shiffrin’s multi-store model of memory, the duration of the Sensory Register (holding information taken directly from the senses) has a brief duration of just half a second.

Attending to and rehearsing information helps to retain information in Short-Term Memory for a duration of up to approximately 30 seconds, and consolidate it into Long-Term Memory.

The duration of Long-Term Memory is considered to be anything greater than 30 seconds – its maximum duration appears to be unlimited.

Research example:

Peterson and Peterson’s 1956 experiment is an early example of research providing insight into Short-Term Memory duration.

Participants were presented with nonsense trigrams (written strings of three consonants, e.g. XQF) and asked to recall them after 3, 6, 9, 12, 15, or 18 seconds.

However, to prevent participants from rehearsing trigrams during these pauses, they counted down in threes from a number set by the experimenters – this is known as an interference task.

The results found an 80% accuracy rate for trigram recall after 3 seconds, but only 10% accuracy after 18 seconds, suggesting that Short-Term Memory duration is limited to roughly 18 seconds when rehearsal is prevented.

Evaluation of Peterson and Peterson (1956):

• There is a good chance that the results are reliable (i.e. can be replicated) as variables can be closely controlled in a laboratory environment.
• However, the results possess low ecological validity (i.e. might not apply to real life), as nonsense trigrams are arguably unrealistic examples of the kind of information people learn on an everyday basis.