A sleep study is hitting the airwaves and the interwebs this week, showing a novel way that our sleep can have repercussions.

But on this occasion, the focus is not on the repercussions for us after a bad night’s sleep - but others.

The conclusion?

Helping others has something to do with how much sleep you got last night.

Slicing the Salami

In all truth, this is a fantastic study - not only due to its novelty, but that it tended to avoid a common behaviour researchers undertake.

Salami Slicing. This means that a single study collected a whole bunch of data, and then instead of publishing one big study, the researchers slice the data into different portions to produce more studies.

Why?

Well, researchers may be looked favourably if they have produced lots of studies. And rewards mainly include promotions, and obtaining grants to do big studies.

I confess that I’ve Salami Sliced a fair bit over my career - and found that the advantage was that you can satisfy that stressful issue of managing a lot of researchers.

For example, as an academic, I would receive about 3 new Honours students per year - meaning I would need to come up with 3 new research project ideas per year.

In 2008, I had 3 students collect data using the same survey. Yet each student had a different project. One was looking at the links between napping and nocturnal sleep - another was looking at how their family’s organisation and sleep hygiene was associated with their sleep (Billows et al., 2009) - and the other one was looking at the links between fluid intelligence (novel problem solving) and their sleep (Johnston et al., 2010).

Because they were all using the same survey, they ended up collecting data for each other - meaning, the amount of data they were able to use for their project was 3 times bigger.

Salami Slicing is often seen as a negative - but I believe there is one caveat (ie, exception to the rule). When the same dataset is being used, yet different research questions are being asked.

This week’s study by lead author Dr Eti Ben Simon did the opposite of salami slicing. It asked a single research question - is sleep related to how much we help others - and did this by using 3 datasets from 3 different studies.

Their 1st study was performed in a laboratory using fancy and very expensive machinery (MRI).

Their 2nd study observed people’s natural day-to-day changes in sleep and helping behaviours.

Their 3rd study looked back on donation data and analysed what happens to the amount people donate when they lose a bit of sleep (ie, the shift to daylight savings).

The Headlines

As I mentioned, both the traditional media and social media have gobbled this study up.

One would think that the mere fact the study was performed at the University of California, Berkeley in the USA, plus the media powerhouse that the USA is, that the USA would be the country promoting this study the most.

It’s actually more promoted in Japan. A country known to be more of a collectivist society, where people work together - as opposed to the United States who could be considered an individualistic society, who are more inclined to look after themselves.

Well, it’s interesting to know that in Dr Ben Simon’s 3rd study looking at actual donations made, that they used data from the USA only, during the years 2001 to 2016.

The other interesting point is that this time period overlaps with 2009-2018, which saw the residents of the USA being the most charitable in the world (Charities Aid Foundation, 2021).

The other really interesting point is that in 2020, the USA dropped from 1st to rank 17th when it came to giving (Charities Aid Foundation, 2021). Indonesia is now ranked 1st in the world.

As per Dr Ben Simon’s study that sleep and donating to charities are linked, does this mean this week’s results - based on the USA (circa 2001-2016) - are still applicable in 2022?

Not ‘One’ Sleep Fits All

When I first read this study, my eye went to the results of Study 2, where people’s day-to-day variations in sleep were analysed alongside their helping behaviours.

Specifically, I found the illustration used to highlight Study 2’s results quite interesting.

They used what’s called ‘Violin Plots’ (because they can look like a violin). Although I guess in this particular study, they look like melting violins (especially the blue one - which foreshadows what I’m about to talk about). As opposed to the violin-looking graphs that Dr Michal Kahn mocked up for our study this year on sleep-deprived parents sexual activity …

Back to the blue and green violins …

The asterix (*) between the green and blue violins below indicates a statistically significant difference. It means that people … Americans … those from the USA … are less helpful after ‘worse sleep quality’.

Now, have a look at those small grey vertical lines within each violin. And can you see that ridiculously tiny grey dot with the white outline within each grey vertical line? They’re pretty similar.

Indeed, if you look at the overall shape between the green and blue violins, they look pretty damn similar.

Possibly the only difference is that the blue one is melting.

So now I’m going to ask you to look closely at the very top of each violin, and the very bottom of each one. Compared to the green violin, the blue one does not have such a pronounced spike on top.

And at the bottom, the blue one looks like it’s melting and is about to go ‘plop’!

My interpretation?

The majority of people don’t change the amount they help others if they experience a bad night sleep. It appears that there’s a small amount of the population who don’t give a f#ck about others if their sleep was ratsh#t last night.

It also appears that in developing these violin plots, the researchers used the nights where people’s sleep changed the most - as opposed to what happens overall. So if you get a bit less sleep, that may not mean you’re gonna be unfriendly today.

The other interesting aspects is that the researchers examined whether differences in people’s chronotype (ie, early-to-late chronotype) influenced helping behaviours. They didn’t find it did. Then again, they didn’t measure chronotype properly. To do so, you need to measure it from people’s weekend sleep (Roenneberg). They measured it with weekday sleep.

But remember - this might not apply to Indonesians! Or Canadians for that matter - they’re so damn friendly they make us Aussies look like assh*les (even though we’re the 5th ranked donators in the world).

Conclusions?

Usually I don’t jump on the bandwagon and blog about the latest trends in sleep.

This week was an exception. It was a terrific study and I commend the researchers for what they’ve done.

But in breaking down this study a bit, what I hope you’ve learned is that it doesn’t apply to everyone.

Because there’s these things called Individual Differences.

People possess certain personality characteristics at different levels - whether it’s how much they help others (Ben-Simon et al., 2022), their ability to get into a flow state (Smith et al., 2017), or how conscientious they are about the consequences of taking risks (Reynolds et al., 2015).

You can apply scientific findings to the majority of people. Just be on the look out for individual differences.

And always read the primary source of information.

• Prof MG