Why do we dream?

Came across this excerpt from 苏青’s《结婚十年》八、少奶奶生活（3） (Su Qing’s Married For Ten Years, Chapter 8: Life as the young mistress of the house (3)), written 1943:

QUOTE

我会剪纸花，找张大红贺贴，我能剪出小兔子，小猪，小剪刀之类。我把这些剪出来的东西贴在她的小圆脸上，鼻梁当中再贴条两头尖的红条儿，等会儿揭去，红花便清楚地印在脸上了。婆婆说：孩子们脸上不可多贴花，因为他们睡时灵魂儿要出去的，及找回来时若认不得自己脸孔了，岂不糟糕！

(My translation) I know how to cut out paper flowers.  I’d find a big red greeting card and cut out things like little rabbits, little pigs and little scissors.  I would stick these on her little round face, also two tapering strips on each side of the bridge of her nose, so that when these are removed, the red flowers would be clearly imprinted on her face.  My mother-in-law said:  Mustn’t stick such things on children’s faces, because their souls go out when they’re asleep, and if the souls cannot recognise their own faces when they get back, wouldn’t that be terrible!

UNQUOTE

When I was a child, the siblings who went to a Chinese school had to do Chinese brush calligraphy.  Grandma would be dozing off in her cane chair in the tropical heat.  For light entertainment, my bored siblings and I would take the calligraphy brushes and paint whiskers on her cheeks, or moustaches on her upper lip, or blacken her glasses (for her to wake up to darkness).  If the grown-ups caught us doing this, we’d be told off for endangering Grandma’s life, as her soul wouldn’t be able to recognise the body when it returned from its wanderings, so it wouldn’t be able to be reunited with her body, and she’d die.  We were told that dreams are really what our souls see in their wanderings when we’re asleep.  We were also told that the reason a sleeping person wakes up with a jump when there’s a sudden noise is that the body has to investigate the cause, so the soul has to come back from its wanderings and jump back into the body very quickly.

(Singapore, 1960s)