WHAT ARE INDIVIDUAL DIFFERENCES IN MEMORY?

Individual Differences refers to variables that make one person different from another.

The cognitive theories of memory tend to ignore these individual differences, focusing instead on processes that are universal and apply to everyone. A few unusual individuals (like H.M. and Clive Wearing) are studied, but only to help researchers understand better how "normal memory" works.

​Cognitive theories explain how individuals may pay different levels of attention to events, may rehearse what they attend to to different degrees and may employ different strategies for encoding memories (like "chunking" or Elaborative Rehearsal). Individuals may have different schemas, which cause them to sharpen or level their memories differently.
CULTURAL DIFFERENCES
Memory processes seem to be universal - all human beings have workng memory, short term and long term memory, etc. However, schemas are exactly the sort of thing that differs from culture to culture. This means that what people choose to remember and how they remember it will be affected by culture.

Mary Mullen (1994) carried out the first cross-cultural research into memory. She asked more than 700 Caucasian and Asian students to describe their earliest autobiographical memories (memories of things that happened to them). Asian students' first memories happened six months later than the Caucasian students' first memories - the earliest memory being from around age 4 for Asians and 3 years 6 months for Caucasians.

Katherine Nelson (2004) links this to upbringing and how our parents talk to us. As children, we encode our memories as we talk over those events with the adults in our life. The more those adults encourage us to spin "an elaborate narrative tale", the more likely we are to remember details about the event later.
Harlene Hayne (2000) studied Maoris from New Zealand and found that they had the best autobiographical memory of all, recalling events from their second year of life, on average up to a year earlier than Caucasians.
In Maori culture there's a very strong emphasis on the past--both the personal past and the family's past... They look backward with an eye to the future. And hence they remember more of their own past as well - Harlene Hayne
In Western culture, over-reliance on computers might be affecting memory: this is "digital amnesia" brought about by a habit of looking up information rather than bothering to remember it. Maria Wimber (2015) points out that when we "outsource" our long term memory to mobile phones and the internet, the brain's ability to make long term memories decreases.
Our brain appears to strengthen a memory each time we recall it, and at the same time forget irrelevant memories that are distracting us... In contrast, passively repeating information, such as repeatedly looking it up on the internet, does not create a solid, lasting memory trace in the same way - Maria Wimber
DEVELOPMENTAL DIFFERENCES
Memory improves with age, peaking in middle life and declining with old age.

A study by Loftus et al. (1992) demonstrates this by showing museum visitors a film then questioning them later. Loftus found that average accuracy was 74%. 26-35 year-olds were most accurate (77%) and the elderly (age 65+) group were the least accurate (56%). 

Not only did children (age 5-10) and the elderly (age 65+) get the lowest scores for accuracy, they were also the most suggestible - when there was a "leading question" they were more likely to produce a false memory.
GENDER DIFFERENCES
There don't seem to be significant gender differences when it comes to memories, although schemas may be different between men and women and this might affect what they remember and how they remember it. For example, Wang (2013) found that women were better than men at recognising photographs of faces they had seen before - but only female faces; when it came to male faces they scored the same as the men.

In Loftus' study of individual differences, males and females scored similarly, except in the elderly group, where females were much more accurate than males (69% versus 43%).
PERSONALITY DIFFERENCES
There is some evidence that introverts have better long term memory (LTM) because they experience more cortical arousal when stressed but extroverts have lower cortical arousal and better short term memory (Cox-Fuenzalisa et al., 2006).

However, a cognitive explanation would be that introverts spend more time thinking about the past (they like to brood) and so they rehearse memories more; extroverts are more focused on the present and so pay more attention to sensory experiences.
Freud's psychodynamic theory of personality is entirely based around memory. Freud argues that people's personalities form when they repress painful childhood memories and create defence mechanisms to deal with unresolved issues in their past. This explains what Freud calls "childhood amnesia" - how we can't recall clearly events in our past from before the age of 5 or 6.

OTHER DIFFERENCES: PHOTOGRAPHIC MEMORY

Another aspect of individual differences is people who have very unusual memory abilities: the so-called "photographic memory" of the person who can recall every minute detail of what they see, read or hear.

For example, Kim Peek was born with brain damage that caused him to suffer many problems but gave him the strange ability to make mental calculations astonishingly quickly and read at speed, recalling in detail everything he read. Peek read 12,000 books in his life and could recall them all.

Although Kim didn't suffer from autism, he inspired the character of Raymond Babbitt in the Oscar-winning film Rain Man (1988). Dustin Hoffman, the actor who played Raymond Babbitt, visited Kim to get an understanding of his abilities and his disabilities.
Photographic memory is sometimes found in people with autism, called autistic savants. For example, Stephen Wiltshire can draw detailed landscapes from seeing a view once.
A condition called eidetic memory occurs in 2-10% of children, who can recall lots of details in something they see once, like car registration plates or book covers. This fades after age 6 and is unknown in adults.

Savantism and eidetic memory seem to be unconnected with IQ.

Adults may have hyperthymesia, also known as Highly Superior Autobiographical Memory (HSAM). James McGaugh (2006) reports the case study of A.J., a woman who could recall every detail of her life from the age of 14.
 "Starting on February 5th, 1980, I remember everything. That was a Tuesday."
However, although A.J. could recall her own experiences in detail, she wasn't particularly good at recalling learned material, like information from a book.
A.J. later revealed her identity as Jill Price, a school administrator. She has explained how the inability to forget anything is a source for her of depression and stress.

Another person with HSAM is Aurelien Hayman, a student from Cardiff. Hayman was the subject of a Channel 4 documentary called The Boy Who Can't Forget. Like A.J., Aurelien Hayman can recall every day of his life; however, unlike A.J., he regards his memory as a gift rather than a burden.

APPLYING PSYCHOLOGY TO INDIVIDUAL DIFFERENCES IN MEMORY
AO2

Photographic Memory

'Photographic memory' is a popular myth that doesn't seem to exist in reality.

There is a small minority of children with eidetic memory, but this only affects visual memory and it disappears after the age of 6 - and very little research involves children younger than that.

There is a small minority of adults with hyperthymesia or HSAM. People like A.J. (Jill Price) have exceptional recall for things they have personally experienced, but don't seem different from anyone else for things they have learned about. They don't function differently in normal memory tests like the Brown-Peterson Technique.

​Savants are people with disorders like autism but have exceptional memories. However, these people make poor samples as they have other cognitive deficits and often suffer from depression - perhaps brought on by their excessive memorising.

​These people might have exceptional memories because they rehearse details that most people don't.

EVALUATING INDIVIDUAL DIFFERENCES IN MEMORY (AO3)
SWAC

Strengths

Individual differences in memory are supported by lots of research. Loftus et al.'s natural experiment in a field setting shows differences in the accuracy and suggestibility of memory between children, adults and the elderly, but also between people with different levels of education and different occupations. There also seem to be gender differences in memory among the over-65s.

Case studies of people with exceptional memories also support the idea of individual differences. McGaugh's case study of A.J. (Jill Price) demonstrates that people with hyperthymesia can recall astonishing details from their own past. Similar amazing memory feats are performed by autistic savants like Stephen Wiltshire.

Weaknesses

There is a generalisability problem with any case study that looks at an unusual person. These individuals might not even be representative of other people with their condition. For example, most autistic people are not autistic savants and most autistic savants don't have Stephen Wiltshire's particular ability at drawing from memory. Similarly, although Jill Price found her hyperthymesia a burden, Aurelien Hayman regarded it positively.

Applications

Individual differences might help the police deal with eyewitnesses. Loftus et al. suggest that children and the over-65s (especially elderly men) have the worst accuracy and are very suggestible, so leading questions must be avoided. Adults in their 30s have the best memories, so their testimony should be taken very seriously.

People with hyperthymesia or savants might be very useful. For example, Kim Peek worked as an accountant for a firm and, when he was replaced, it took two normal accountants and a computer to do his job. However, these people are still as suggestible as anyone else so their memories can be affected by leading questions or schemas. Moreover, there are often social or emotional problems linked to these conditions.

Comparisons

It may be that normal memory models explain individual differences. For example, the Multi Store Model suggests that savants and people with hyperthymesia simply rehearse their LTM much more than ordinary people. This is backed up by the brain scans that suggested that A.J.'s brain functioned in the same way as people with Obsessive Compulsive Disorder (OCD).

Reconstructive Memory might explain these differences too. Schemas explain why some people are more suggestible than others. Children might not have developed schemas yet and the elderly might have out-of-date schemas. Educated people might use different schemas from uneducated people and groups like the salespeople and technicians might learn different schemas from unemployed people. However, this doesn't explain the poor accuracy of police officers and lawyers, who ought to have scored higher.

EXEMPLAR ESSAY
How to write a 8-mark answer

Evaluate the importance of individual differences in research into memory. (8 marks)
  • A 8-mark “evaluate” question awards 4 marks for describing individual differences (AO1) and 4 marks for AO3 (Evaluate). Don't forget to add a conclusion so that you can get into the top band (7-8 marks).

Description
Individual differences are things that make people distinctive, like their age and sex and education. It includes special abilities like photographic memory.
Loftus et al. did research into individual differences and found that children and old people were less accurate and more suggestible than adults in their memory ability.
Loftus also showed that college students have above-averagely accurate memories but are just as suggestible as anyone else.
Photographic memory isn't real, but some people do have hyperthymesia or Highly Superior Autobiographical Memory. People like A.J. can remember every day of their own lives.

Evaluation
Individual differences are backed up by natural experiments that compare different age groups, occupations, educational levels and genders. They are also backed up by case studies of exceptional individuals. This suggests they are not a 'myth'.
There might be an application for individual differences for the police. Loftus et al.'s research suggests which eyewitnesses should be trusted and which are unreliable.
Another application might be for cognitive psychologists themselves. Loftus et al. also suggests that college students are fairly representative samples. Although they are more accurate than average, they are just as suggestible.
A final application might be for autistic savants who could use their abilities for jobs involving memory (like Kim Peek who worked as an accountant).

Conclusion
There's a lot of evidence that individual differences exist but not much about what causes them. Despite Rubenstein's claim that college students are overused in research, individual differences don't seem to be so huge that students are completely unrepresentative.

  • Notice that for a 8-mark answer you don’t have to include everything about individual differences. I haven’t mentioned the other savants or cases of HSAM. I haven’t described the details of Loftus et al.'s study. But I have tried to make the two halves – Summary and Application – evenly balanced.