Findings:
Found that the average STM span was between 5 and 9 items. Digits were recalled better than letters. STM span increased with age.
Conclusions:
Findings show that STM has a limited storage of between 5 and 9 items. The capacity of STM is not determined by the nature of the information to be learned but the size of the STM span, which is fairly constant across individuals. STM span increased with age which maybe due to increasing brain capacity or improved memory techniques.
Criticisms:
- The research lack mundane realism as the digit span is not representative to everyday memory demand and the artificiality of the task may have biased results. Letters and digits are not meaningful information and so may be remembered less well than more meaningful information. Thus, the capacity of STM may be greater for more everyday memory.
- Findings have been usefully applied to improve memory. For example, telephone numbers, postcodes, are based on the idea of total digit span.
Duration in short-term memory – Peterson and Peterson (1959)
Aim:
Measure the duration of STM. Also a reason to include the interference task was to stop participants from rehearsing the trigrams.
Procedure:
Participants were shown a trigram (three constants such as BVM or CTG). They were then asked to recall them either after 3,6,9,12,15 or 18 seconds. Participants were given an interference task between initial presentation of the trigram and the time when they were asked to recall it. The interference task was to count backwards in threes in a three-digit number.
Findings:
Peterson and Peterson found that participants were able to recall trigrams after three seconds. They recalled fewer after 6 seconds and at 18 recall was very poor.
Conclusions:
Is that memory trace in short-term memory has just about disappeared after 18 seconds. It’s as if the information is written on a magic slate and as time passes the writing fades away.
Criticisms:
- On the positive side we the simple nature of the experiment means that we can clearly identify the effect of the independent variable (time delay) on the dependent (recall).
- The research lack mundane realism as a recall of trigrams are not representative in everyday memory demands.
Duration in long-term memory – Bahrick ET AL (1975)
Aim:
To find out if people do have very long-term memories that are not confabulated.
Procedure:
They asked 392 ex high school students of various ages to free recall names of any classmates and also showed them a set of appropriate photographs and asked them to identify individuals
Findings:
Even after 34 years ex-students were still able to name 90% of photographs of their classmates. After 48 years this had declined to 80% for name recognition and 40% for face recognition. Free recall was considerably less accurate: 60% accurate after 15yrs and only 30% accurate after 15yrs.
Conclusions:
The findings show that classmates are rarely forgotten once recognition clues have been given. The finding also shows that recognition is better than recall. It can be concluded that memory may not be as unreliable and subject to confabulation as is commonly perceived.
Criticisms:
- Classmates’ faces are very particular types of information. They might have emotional significance and there will have been opportunity for a great deal of rehearsal given the daily contact classmates will have experienced. Findings on VLTM cannot be generalised to other types of information.
- Compared to the vast majority of memory research, which takes place in the laboratory, this had high mundane realism. This is more natural.
Flashbulb Memory- Conway ET AL (1994)
Aim:
Aimed to show that if the public event has a distinctive meaning and emotional compact for the participant then it will be more memorable and thus create a flash bulb memory.
Procedure:
Used Mrs Thatcher’s resignation as the public event. This was a natural experiment. 923 participants were selected, two-thirds from the UK and one third from other nationalities, mainly North Americans. All of the participants were interviewed with a fortnight of Mrs Thatcher’s resignation and 369 were interviewed 11 months later. The elapsed time gave opportunity for forgetting. Participant’s memories of the event were assessed for accuracy and detail over time as indicative of memorability and thus flash bulb memory.
Findings:
At 11 months 86% of the UK participants still had a vivid, detailed, accurate memory of the event, compared to only 29% of the participants from other countries.
Conclusions:
The difference between the UK and other nationalities suggests that the public events that have more cultural relevance are more likely to be remembered by individuals from that cultural. Things with more emotional impact are more memorable and create a flash bulb memory. It can be concluded that flash bulb memories are more enduring and so less subject to forgetting than other types of memory.
Criticisms:
- It had a sample drop-off, which is a weakness of longitudinal research. The sample drop-off may of left biased sample for the second interviews, which may have distorted the difference found between the UK and other nationalities. They may lack validity, which reduces their meaningfulness and generalisability.
- It is difficult to assess whether memorability is due to the distinctiveness and emotional impact of the event or the fact that important events are often rehearsed.
Repression – Levinger and Clark (1961)
Aim:
To look for repression and to see if there is a difference between participants recall of their associations to neutral or negative emotionally charged words.
Procedure:
Asked participants to generate associated words to a series of words presented by the researchers. Some of the words were neutral and others were emotionally arousing. When asked to recall participants rather would recall the neutral than the emotional.
Findings:
Participants have greater difficulty remembering there associations to negative emotionally charged words than to neutral words. A difference in recall speed was found. Also it was found that negative emotionally charged words produced higher galvanic skin response.
Conclusions:
It was concluded that the greater the difficulty in the recall of negative emotionally charged words compared to neutral words was explained by the repression. This was supported by the galvanic skin response data, which showed that the emotionally charged words created more arousal, which may have led to them being repressed into the unconscious to reduce anxiety.
Criticisms:
- The level of arousal may be a confounding variable as whilst immediate tests of recall found the emotionally charged words to be poorly recalled, delayed recall tests have found that emotionally charged words are remembered better than neutral words. This contradicts repression as an explanation to the findings. If repression had occurred than the words should still be repressed, so recall should not improve.
- It lacks mundane realism as emotionally charged words have much lower threat than real life anxiety provoking stimuli.