Remembering an email address long enough to write it down, following a conversation, or remembering the beginning of a sentence you’ve just read. Working memory makes these tasks possible. A recent study conducted by a team of psychologists has shed light on strong connections between working memory and sleep, mood, and age. What are the effects of these three factors on working memory?

A component of short term memory, working memory is used to store, temporarily maintain, and manipulate useful information for performing cognitive tasks, such as reasoning and comprehension. It plays a crucial role in many cognitive functions (language, action planning, etc.). Research has already established a link between each of the factors listed above (age, sleep, and mood) and overall working memory function. But the present research, conducted by Weiwei Zhang, a professor of psychology at the University of California, Riverside, looks specifically, for the first time, at how these factors are associated with memory quality and quantity.

The scientists carried out two studies for their research. In the first, they invited 110 students to give self-reported measures (collected using questionnaires) on their sleep quality and mood (depressed or not). In the second study, they recruited 31 subjects ages 21 to 77. In both protocols, each participant’s working memory was evaluated using a short-term memorization task. The researchers measured both the quantity of the recalled information (quantitative aspect) as well as its accuracy (qualitative aspect).

The results of the first study showed that poor sleep quality and depression could independently lead to reduced working memory capacities in terms of memory quantity. The second study confirmed this tendency and indicated that age could be negatively correlated with memory quality. In other words, our working memory becomes less accurate as we age. From this point of view, this research is the first to isolate the effects of age, sleep, and mood on working memory quantity and quality. The results of this study, published in the Journal of the International Neuropsychological Society, show the dissociable effects of these three factors and highlight the importance of evaluating different aspects of working memory (quantitative and qualitative). These findings could be used to implement interventions and treatments to counteract the negative impact of these factors on memory.

In the meantime, Professor Zhang says that, “For the mind to work at its best, it is important that senior citizens ensure they have good sleep quality and be in a good mood!”.