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Study Notes

​Duration of Long-term Memory

AS, A-Level
AQA, Edexcel, OCR, IB

Last updated 22 Mar 2021

Bahrick (1975) investigate the duration of long-term memory using 392 American university graduates. The graduates were shown photographs from their high-school yearbook and for each photograph participants were given a group of names and asked to select the name that matched the photographs.

Bahrick found that 90% of the participants were able to correctly match the names and faces, 14 years after graduating and 60% of the participants were able to correctly match the names and faces 47 years after graduation. Bahrick concluded that people could remember certain types of information, such as names and faces for almost a lifetime. These results support the multi-store model and the idea that our long-term memory has a lifetime duration (at least 47 years) and is semantically encoded.


Bahrick’s research used a sample of 392 American university graduates and therefore lacks population validity. Psychologists are unable to generalise the results of Bahrick’s research to other populations, for example students from the UK or Europe. As a result, we are unable to conclude whether other populations would demonstrate the same ability to recall names and faces after 47 years.

Furthermore, Bahrick found that the accuracy of long-term memory was 90% after 14 years and 60% after 47 years. His research is unable to explain whether long-term memory becomes less accurate overtime because of a limited duration, or whether long-term memory simply gets worse with age. This is important because psychologists are unable to determine whether our long-term memory has an unlimited duration (like the multi-store model suggests), which is affected by other factors, such as getting old, or whether our long-term memory has a limited duration.

Finally, it could be argued that Bahrick’s study has high levels of ecological validity as the study used real life memories. In this study participants recalled real life information by matching pictures of classmates with their names. Therefore, these results reflect our memory for real-life events and can be applied to everyday human memory.

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