All-nighters are bad for women’s working memory

Posted on under Today's research

Over the last few decades, a wealth of evidence has accumulated to suggest that a lack of sleep is bad for mind and body. One of the things that lack of sleep is bad for is working memory (see previous TRs). This is important for keeping things in mind for brief periods of time (Where are my keys? What’s the name of the person I’m here to see?). It also facilitates reasoning and planning. Interestingly a team of sleep scientists has now demonstrated that acute sleep loss impacts working memory differently in women and men.

What the researchers say: In the current study 24 young adults performed a working memory task in the morning following either a full night of sleep or a night of wakefulness. Half of the participants were females, and half were males. The set-up of the working memory task was to learn and remember 8-digit sequences. Contrary to expectations, males’ working memory performance remained unaffected by sleep loss. In contrast, females remembered fewer digits after sleep loss than after a night of sleep.

Importantly, even though their performance was reduced, females were unaware of the drop in working performance when sleep-deprived. A lack of awareness of impaired mental performance could increase the risk of accidents and mistakes, which can be dangerous in many private and occupational situations, both for the sleep-deprived person as well as for others, they observed.

“Our study suggests that particular attention should be paid to young women facing challenges in which they have to cope with both a high working memory load and a lack of sleep. However, it must be kept in mind that we have not tested whether the observed sex-dependent effects of sleep loss on working memory during morning hours would also occur at other time points of the day. In addition, while our data suggest that sleep loss impairs working memory in a sex-dependent manner, this does not mean that the sex-differences we observed can be generalized to other mental or physical measures of how we are affected by sleep loss,” said the lead author.

So what? There are a lot of problems with this study—particularly in its methodology—which I won’t go into. However it does highlight an important point which a number of recent studies—most of which are in past TRs—have also noted: that there are real cognitive, genetic and other biological as well as experiential differences between the genders (hardly surprising since even the brains of men and women are shaped somewhat differently). Often the different way women and men operate is something which organizations—and society at large—unfortunately don’t take into account when allocating jobs.

The important point here is that difference is not the same as inequality. That women may do worse at remembering a string of numbers after an all-nighter is pretty meaningless in itself. If it’s true then it probably illustrates an interesting evolutionary adaption: women may need to clear their short-term memories of inessential data in order to remember something more significant and relevant to them. It would be really fascinating to study that in more detail.

What now? Neither men nor women should be excluded from any occupation—that’s a given. However we should be aware of the very real differences that evolution has created and cater to those so that both (or, indeed, all) sexes can find fulfillment. That is a serious task that all organizations must face as we find out more and more about how all humans operate. We are not the same, nor should we be made to try to be—and that’s the point.

For example, overall, women have been shown to be better leaders than men in normal times because they tend to be more affiliative and to have a greater capacity to listen to opinions contrary to their own (I realize this is a vast generalization, with an equally vast number of exceptions but it is still statistically true). However many women leaders seem to feel that they have to act like men to be accepted, and this obviously is a pity.

Men and women may well react differently in any situation and any organization needs these differences in order to thrive.


By Dr Bob Murray