Individual Differences In Memory

Some people remember more from when they were little (under age five) than others. Some people can't remember anything from that early! People who share certain memories may remember events very differently. A child's memory of a favourite birthday party may be very different from the parents, for example. There are so many individual differences in memory!

• What are some examples of types of memories?
• How does the dual processing theory of mind explain individual differences in working memory capacity?
• What is one example of individual differences in working memory and reading?
• How do individual differences affect the accuracy of eyewitness memories?
• What is one example of individual differences in colour memory?

Individual Differences in Episodic Memory Ability

Memory processes involve encoding, storing, and retrieving past events and knowledge. Research has found individual differences in memory that can impact memory processes. These include:

• Trauma.
• Age.
• Brain activity.
• Schemas.
• Processing speed.

Fig. 1 Individual differences in memory

There are different types of memories. Individual experiences shape some of these memories, examples of which are episodic and autobiographical memories.

Regarding episodic memories, individual differences exist in the ability to form and retrieve them. Kirchhoff (2009)¹ suggested the individual differences responsible for this are as follows:

Fig. 2 Individual differences in episodic memory ability

Herlitz et al. (1997)² found women performed better than men on episodic memory tasks. There were no gender differences on tests of semantic memory. In general, however, there do not appear to be gender differences in memory.

Individual Differences in Working Memory Capacity and Dual-Process Theories of the Mind

Earlier, we've mentioned two types of memory, episodic and autobiographical memory, which consist primarily of experiences and details of past events. Another important type of memory, a term often used in psychology, is our working memory.

Individual differences in working memory are differences in people's ability to direct their attention. Attention control is part of the central executive component of the working memory model (Baddeley & Hitch, 1974)³. In addition to how the brain processes, encodes, and stores stimuli directed to the other model components.

These individual differences in working memory reflect differences in accomplishing cognitive tasks such as:

• A directed search of the necessary information in situations with active interruptions or distractions. Those with high working memory capacity showed faster and more accurate retrieval of information than those with low working memory capacity.

• Ongoing activation of information in mind and the ability to resist distraction. Those with high working memory capacity (WMC) showed greater resistance to distraction on different memory tasks than those with low working memory capacity.

• Keeping out information irrelevant to a specific goal or task. In testing fluency of memory retrieval from different categories (category fluency task), those with low working memory capacity committed more repetitions of category items. They were less able to pay attention to their responses than those with high working memory capacity.

The dual-process theory of the mind assumes there are two ways in which thoughts can arise:

1. Automatic – this system is unconscious and useful in instantaneous thinking.
2. Controlled – this system is intentional and applies when a person must make a conscious effort to think. This system is useful when people make rational, calculated thoughts.

People with lower working memory capacity rely on the automatic system. On the other hand, people with higher working memory capacity use the controlled system. When there are additional tasks (increase in information load), people with higher working memory capacity are more impaired than people with lower capacity. Working memory capacity can affect processing ability and performance on specific tasks.

Individual Differences in Working Memory and Reading

We understand that memory is a form of cognition necessary for other cognitive abilities to work efficiently. These cognitive abilities influenced by memory include reading, listening, and attention skills. Individual differences in memory can also impact different types of memory.

Daneman and Carpenter (1980) found that performance on reading comprehension tasks may result from differences in working memory capacity. The study found that people with poor reading comprehension may need to limit the amount of information they store in their working memory. People with good reading skills were more effective at chunking. This study shows that working memory capacity and processing influence reading comprehension ability.

Another notable difference in working memory and reading between individuals is the ability to make sense of a word in a sentence with multiple meanings. In this sentence, “I saw a bat,” one might think of baseball equipment or an animal.

Miyake et al. (1994) suggested that high-span readers (large working memory) can hold multiple meanings in their thoughts. This process allows them to select the correct meaning aligned to the context when the researchers provided the context (e.g., I saw a bat fly out of the cave). In low-span readers (small working memory), reading times were slower when the context pointed to the less typical meaning of the word.

Individual Differences in Accuracy of Eyewitness Memory

The Yerkes-Dodson law explains why there are individual differences in the accuracy of eyewitness testimony. The theory is that the amount of fear one feels as a witness to a crime affects one's recollection of the events:

• Low and high anxiety levels – memory accuracy is minimal.
• Moderate levels of anxiety are the optimal level where memory is most accurate.

Memory loss after a traumatic event can occur due to physical trauma. However, some people forget memories of an event because they repressed the memory.

There are also links to sex differences that affect the accuracy of eyewitness memory. Studies suggest that females can recognise and remember other people's facial features better than males. But males perform better in remembering details about the event, including the surroundings, as they tend to observe the environment more than females. Additionally, how men and women think about crime reflects individual differences in their cognitive schema, which can also impact the accuracy of eyewitness memory.

Because we all have different life experiences, our schemas are different, influencing how we remember things. Our memories undergo reconstruction to fit our schema.

Fig. 3 Memory reconstruction to fit a schema

Individual Differences in Colour Memory

Research has shown that people are more likely to pay attention to coloured objects. Attention to information is vital in the process of encoding and storing memories.

Rindermann et al. (2020) found that blind and visually impaired children have higher working memory capacity than non-visually impaired children. This finding suggests the brain can compensate for deficits due to visual impairments. Thus, perceiving colours does not necessarily lead to an improvement in memory.

There is also an association with individual differences in working memory and accurately remembering a specific colour, even with changes in lighting conditions (colour constancy). One research showed that those with high working memory performed better in recalling the same colour under a different illumination than those with low working memory. But there were no differences in colour recollection if viewed under the same lighting conditions.