To Sleep… Perchance to Drown

Science is so simple; I mean you just have to look around –or at least listen. Take unihemispheric slow-wave sleep (USWS) for example. This is where only one side of the brain sleeps while the other side stays alert. It’s a great thing; if you’re an animal that needs to sleep, but could get eaten if you do, it would be a good idea to keep the burglar alarm connected at all times. Or, to use a more current analogy, video-surveillance with motion detectors –a kind of CCTV for the brain.

It’s an adaptation known to exist in Beluga whales, some dolphins and seals, and maybe in certain types of migrating birds. It makes sense, of course. If you’re supposed to breathe air, and you’re somewhere in the middle of the ocean, how could you ever go to sleep? Even domestic chickens that are rarely found out there, exhibit USWS. So how about us?

Well, now that I’ve retired, I find that I can sleep pretty well anywhere, although, similar to the chicken, I tend to avoid it while swimming and in other circumstances where I might be in danger –driving comes to mind. Also while shopping, because I would probably buy a lot of sugary things which would also put me at risk.

But USWS has not been a priority for mammals for some reason. It has been argued that to do this in a creature with a need for close integration of both hemispheres of the brain (like us) might compromise some cerebral functions –unless, of course, being eaten trumps being smart. So, if becoming a porterhouse steak is not a major threat, evolution would probably weed USWS out.

And yet… Could we creative mammals have retained some vestigial remnants of this ability -like some of us have retained the capability of going bald? It’s a question on which I wouldn’t have dared to speculate until reading this short little blurb on my BBC News app. –fully awake at the time, you understand:

It would seem that a study done at Brown University in Rhode Island by Yuka Sasaki suggested that ‘People sleep less well in an unfamiliar place as the brain’s left side stays alert for danger.’ Well, at least more responsive to sound –but that’s a start, eh?

And yet I could have told you that, come to think of it. I first heard evidence of its existence while I was sitting at a little table in Starbucks having my coffee and sausage-and-egg breakfast sandwich. It’s really very good, although if you don’t let it cool off a bit first, your level of awareness can fluctuate markedly. Anyway, I was just waiting for it to cool down, and my ears, having little else to do, were on patrol.

Two women were sitting at the next table, heads together, whispering loudly at each other. Nothing attracts attention like a whisper, so I focussed immediately. Normally, of course, I don’t focus; I just let it drift in, but they sounded so… angry, I thought it might be important.

“I don’t know how he thinks he can get away with it,” the blond with the sporty lipstick hissed. I could see a little trail of bubbles on her coffee where the whisper had bounced.

“But how could you tell what he was doing, Edith? You said it was the middle of the night and as dark as freshly dyed hair?”

I have to say that I was impressed with her simile –her own hair requiring a few touch-ups, notwithstanding. I’d have taken it personally, I think.

“I thought I was dreaming at first…” she hesitated mid-whisper. “Actually, it was a part of my dream…”

The woman with the roots, waited patiently for her to continue. You can’t rush this kind of thing.

“I was in a club sitting at the bar, when some guy sat down next to me. He was hot, but only for his phone. I could hear him tapping at it, even though he’d turned off the keyboard sound…”

“Didn’t Dan turn his off too, Edie?”

Duh. She was missing the whole point, and Edith just withered her with a ‘you’re not very smart, are you?’ stare that I could almost feel at my own table. Perhaps I had been leaning a bit over to their side under the guise of rebooting my sandwich –I’d taken it out of the bag to cool and then had to reconstruct it for consumption. But they were too wrapped up in the intrigue to notice my proximity. Besides, they were whispering, so the secret was safe.

“So you think Dan was texting someone from your bed in the middle of the night, Edith?” The woman had to get her rumours straight if she was going to pass it along.

“I know he did!” Edith whispered emphatically and then nodded –a little sarcastically, I thought, but I can’t say for sure because the little egg patty had slipped onto the table somehow and I had to encourage it back onto the bun. I may have missed something.

But even in the midst of my own food angst I managed to anticipate the response: “How do you know?” She was genuinely puzzled.

I think Edith sighed –I was busy, remember- but a whispered sigh is far more difficult to identify… Or at least attribute it to one party or the other.

“I checked his phone when he got up to pee,” she whispered with an obvious frisson of pride.

“And…?” The woman was evidently drinking decaf.

“And I was right…” Edith sat back, clearly satisfied that he couldn’t put one over on her!

The other woman shook her head admiringly. “Edie, it’s like you’ve got ears on the back of your head…”

Edith was not happy with that analogy, but nonetheless, she was smiling. “Sometimes, you know, I think I can sleep with one eye open…”

She’d have made a good chicken, I decided, and tucked into my rescue-sandwich.


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