A Level Psychology: Coding, Capacity and Duration of Memory:

A Level Psychology: Coding, Capacity and Duration of Memory: Coding definition

The format in which information is stored in the various memory stores.

A Level Psychology: Coding, Capacity and Duration of Memory: Capacity definition

The amount of information that can held in memory

A Level Psychology: Coding, Capacity and Duration of Memory: Duration definition

The length of time information can be held in memory

A Level Psychology: Coding, Capacity and Duration of Memory: short-term memory (STM)

The limited-capacity memory store. Coding is mainly acoustic capacity is between 5 and 9 items on average, duration is between 18 and 30 seconds.

A Level Psychology: Coding, Capacity and Duration of Memory: long-term memory (LTM)

The permanent memory store. Coding is mainly semantic (meaning), it has unlimited capacity and can store memories for up to a lifetime.

A Level Psychology: Coding, Capacity and Duration of Memory: Research on coding

Once information gets into the memory system, it is stored in different formats, depending on the memory store.

The process of converting information information from one form to another is calling coding.

Baddeley (1966) gave different lists of words to four groups of participants.

Participants were shown the original words and asked to recall them in the correct order.

When they had to do this recall tasks immediately after hearing it, they tended to do worse with acoustically similar words.

If participants were asked to recall the word list after a time interval of 20 minutes, they did worse with the semantically similar words.

This suggests that information is coded semantically.

A Level Psychology: Coding, Capacity and Duration of Memory: Research on capacity - Digit span

How much information can the STM hold at any one time.

Jacobs (1887) developed a technique to measue digit span.

The researcher gives 4 digits and then the participant is asked to recall these in the correct order out loud.

If this is correct the researcher reads out 5 digits and so on until the participant cannot recall the order correctly.

This determines the individual's digit span.

Jacobs found that the mean span for digits across all participants was 9.3 items.

The mean span for letters was 7.3.

A Level Psychology: Coding, Capacity and Duration of Memory: Research on capacity - span of memory and chunking

Miller made observations of everyday practice. He noted that things come in sevens: There are 7 notes on the music scale,7 days of the week, 7 deadly sins and so on. This suggests that the span (or capacity) of STM is about 7 items. Miller also noted that people can recall 5 words as well as they can recall 5 letters or digits, they do this through chunking.

A Level Psychology: Coding, Capacity and Duration of Memory: Research on duration- Duration of STM

Peterson and Peterson tested 24 undergraduate students. Each student took part in eight trials. On each trial the student was given a trigram (e.g. YGC) to remember. They were also shown a 3 digit number, the participants were asked to count backwards from this three digit number until told to stop. The counting backwards was to prevent rehearsal. On each trial they were told to stop after a certain amount of time 3,6,9,12,15 or 18 seconds. Their findings found that STM has a duration of up to 18 seconds.

A Level Psychology: Coding, Capacity and Duration of Memory: Research on duration- Duration of LTM

Harry Bahrick and colleagues (1975) studied 392 participants from the Amercian state of Ohio who were aged between 17 to 74.

High school yearbooks were obtained from the participants or directly from some schools.

Recall was tested in various ways such as a photo recognition test, free recall test.

Participants who were tested within 15 years of graduation were about 90% accurate in photo recognition.

After 48 years, recall declined to about 70% for photo recognition.

This shows that LTM can last a very long time.

A Level Psychology: Coding, Capacity and Duration of Memory: Evaluation of Coding, Capacity and Duration of Memory - Artificial Stimuli

One limitation of Baddeley's study was that it used quite artificial stimuli rather than meaningful material.

The word lists had no personal meaning to participants.

This means we should be cautious about generalising the findings to different kinds of memory task.

For example, when processing more meaningful information, people may use semantic coding even for STM tasks.

This suggests that the findings from this study have limited application.

A Level Psychology: Coding, Capacity and Duration of Memory: Evaluation of Coding, Capacity and Duration of Memory - Lacking Validity

One limitation of Jacob's study is that it was conducted a long time ago.

Early research in psychology often lacked adequate control.

For example, some participants may have been distracted while they were being tested so they didn't perform as well as they might.

This would mean that the results might not be valid because there were confounding variables that were not controlled.

However, the results of this study have been confirmed in other research, supporting its validity.

A Level Psychology: Coding, Capacity and Duration of Memory: Evaluation of Coding, Capacity and Duration of Memory - Not so many chunks

One limitation of Niller's research is that he may have overestimated the capacity of STM.

For example, Cowan (2001) reviewed other research and concluded that the capacity of STM was only about four chunks.

This suggests that the lower end of Miller's estimate (five items) is more appropriate than seven times.

A Level Psychology: Coding, Capacity and Duration of Memory: Evaluation of Coding, Capacity and Duration of Memory- Higher external validity

One strength of Bahrick et al.'s study is that it has higher external validity.

Real life meaningful memories were studied.

When studies on LTM have been conducted with meaningless pictures to be remembered, recall rates were lower (Shepard 1967)

The downside of such real-life research is that confounding variables are not controlled, such as the fact that Bahrick's participants may have looked at their yearbook photos and rehearsed their memory over the years.

A Level Psychology: Coding, Capacity and Duration of Memory: Evaluation of Coding, Capacity and Duration of Memory- Meaningless stimuli in STM study

A limitation of Peterson and Peterson's study is that the stimulus material was artificial.

Trying to memorise consonant syllables does not reflect most real-life memory activities where what we are trying to remember is meaningful.

So we could say that the study lacked external validity.

However, we do sometimes try to remember fairly meaningless things, such as phone numbers, so the study is not totally irrelevant.

A Level Psychology: Coding, Capacity and Duration of Memory: Evaluation of Coding, Capacity and Duration of Memory- Criticising Peterson and Peterson

One explanation for why we forget things in STM is that the memory trace simply disappears if not rehearsed (spontaneous decay).

An alternative explanation is that the information in STM is displaced - STM has a limited capacity and any new information will push out what is currently there.

In the study by Peterson and Peterson participants counted down during the retention interval.