Photo/Illutration A person looks at a mobile phone screen in the dark before going to sleep. (Asahi Shimbun file photo)

I wonder who was the first person to use the Japanese expression “neochi,” which translates literally as “to fall asleep” but more in the sense of dozing off inadvertently.

I witnessed a perfect example of this in a young man at a nearby library the other day, who was snoozing with his head bowed at a perfect angle.

Apparently a student preparing for a university entrance exam, he had reference books around him. He might have stayed up late the previous night.

He looked so content in sleep, but I worried about him a bit. Wouldn’t napping like that affect his health? And how are his studies going?

Because I myself was a constant catnapper in my student days, this simple question popped in my head: What, exactly, is sleep?

According to Takeshi Sakurai, 57, a sleep expert and professor at Tsukuba University whom I interviewed, the brain seems to engage in maintenance work while we sleep.

“It ‘saves’ important memories and deletes those that aren’t important,” he explained. “We don’t want redundant files cluttering our computers, do we?”

Our brain processes massive data while we are awake, like when we try to memorize English words and learn mathematical formulae by heart.

But the brain switches to a different mode while we are asleep, Sakurai said. It decides which memories to hold on to, getting us prepared for new studies.

This reminded me of Chinese philosopher Zhuangzi's “Butterfly Dream Parable” which goes: “Once upon a time, I dreamed I was a butterfly ... Soon I awaked, and there I was, veritably myself again. Now I do not know whether I was then a man dreaming I was a butterfly, or whether I am now a butterfly, dreaming I am a man.”

We all sleep through one-third of our lives, but we don’t know who we are during those hours.

“Neochi moshimoshi” is a new expression today meaning a smartphone chat between lovers until one of the partners falls asleep.

“Falling asleep inadvertently in the middle of something is a sign of sleep deficiency, and that’s not good,” Sakurai warned.

So, before I doze off while writing this, here’s my advice to students cramming for their entrance exams and young lovebirds: “Be careful of sleep deprivation.”

--The Asahi Shimbun, Feb. 5

* * *

Vox Populi, Vox Dei is a popular daily column that takes up a wide range of topics, including culture, arts and social trends and developments. Written by veteran Asahi Shimbun writers, the column provides useful perspectives on and insights into contemporary Japan and its culture.

Related News