Capacity- this is a measure of how much can be held in memory. It is represented in terms of bits of information, such as number of digits.

Coding- (also 'encoding') The way information is changed so that it can be stored in memory. Information enters the brain via the senses (e.g. eyes and ears). It is then stored in various forms, such as visual codes (like a picture), acoustic codes (sounds) or semantic codes (the meaning of the experience).

Duration- a measure of how long a memory lasts before it is no longer available

Long-term memory (LTM)- your memory for events that have happened in the past. This lasts anywhere from 2 minutes to 100 years. LTM has potentially unlimited duration and capacity and tends to be coded semantically.

Short-term memory- your memory for immediate events. STMs are measured in seconds and minutes rather than hours and days, i.e. a short duration. They disappear unless they are released. STM also has a limited capacity of about four items or chunks and tends to be coded acoustically. This type of memory is sometimes referred to as working memory

George Miller wrote about the magic number seven plus or minus two

The span of immediate memory is about seven items - sometimes a bit more

People can recall five words as well they can recall five letters- we chunk things together and can then remember more

Peterson and Peterson told participants to recall consonant syllable after a retention interval of 3,6,9,12,15 or 18

Participants on average, were 90% correct over 3 seconds, 20% correct after 9 seconds and only 2% correct after 18 seconds

STM has a very short duration - less than 18 seconds - as long as verbal rehearsal is prevented

Harry Bahrick et al. tested 400 people of various ages (17-78) on their memory of classmates

A photo recognition test consisted of 50 photos, some from the participant's high-school yearbook

List the names they could remember of those in their graduating class

90% accurate in identifying faces. After 48 years, this declined to about 70% for photo recognition. Free recall was about 60% accurate after 15 years, dropping to 30% after 48 years