Is it true that babies dream but can't dream about themselves? originally appeared on Quora: the place to gain and share knowledge, empowering people to learn from others and better understand the world.

Answer by Fabian van den Berg, Neuroscientist, on Quora:

Peering into the minds of babies is very difficult, especially when it comes to subjective experiences such as dreams. The problem is that we can’t ask babies what they are dreaming about, they can’t tell us.

We know babies sleep, they show similar wakefulness-rest-REM patterns throughout the day. They already do this in the womb, and after they are born you don’t need to be a scientist to notice the difference between a sleeping and an awake baby.

Adults dream the most in their REM phase, we know that because they can tell us. It is tempting to assume that the same happens in babies. They have REM sleep, we have REM sleep, we dream during REM so they dream during REM.

That’s a dangerous assumption though. Infants are not tiny adults, they don’t have the same abilities or experiences we have. Their world is very different from our own, they see the same events without any knowledge or experience, unbothered by past events. Just because we experience something, does not mean they experience it the same way. It’s comparing a human to a cat, monkey, or alien. They do become like us, eventually, but they aren’t like us yet.

They have consciousness, to some degree at least (depending on your views on the topic), even before they are born. Self-awareness is the one they don’t have yet, which is the knowledge/realization that they are a thing separate from other things. That’s where the mirror test comes in, they don’t recognize themselves in the mirror before 18 months or so, which leads to the conclusion that before that time they don’t have a concept of self.

Knowing thyself in this sense has little effect on the ability to dream, more so on the content of that dream. Likely they won’t dream from their own personal perspective since they don’t have that yet.

Some scientists believe that the lack of development and experience means babies don’t dream. Dreams the way we experience them wouldn’t arise until age 7 or 8. Any parent would know that kids definitely have nightmares and dreams before 7, but the idea is that those dreams/nightmares are superficial and not as vivid as adult dreams. The ages of 7/8 are important because that’s when they start developing a sense of self (an identity), not to be confused with the ability of self-awareness.

But this isn’t believed by all, far from it. The other side claims that babies most definitely dream. Processing the massive influx of information they receive when they are awake. People, animals, objects, language, feelings, so many new things… no wonder they get tired so much.

The content of a baby-dream will be very different from ours but serves a clear purpose. One theory about dreams is that they simulate danger, and children are very vulnerable. Their brains simulate a lot of dangers, setting up scenarios and how to deal with them. Which is why children have more nightmares than adults, adults kinda dealt with most scenarios already (and why nightmares come back when you have to do an important presentation).

For now, we can’t say for certain if babies dream. We don’t have the tools to measure it objectively (yet). We can say that if they do dream their dreams will be very different from what you or I experience.

Like many things, the experience of an infant is very alien to us. There is no language, no sense of self, no previous experience, no model of the world. It’s just pure sensory information that a young brain is trying to untangle.

The lack of self-awareness doesn't affect the ability to dream, but it does mean the content is very different. It would also mean they won’t dream about themselves, at least they won’t experience it as a dream about themselves. It is one of the aspects that make us think their dreams are different… if they have them.

Once we get to the point that we can translate brain signals to visual images, then we will have some very interesting result about this. Until then, the mystery remains.