Brain Rules (Updated and Expanded)

part and purely adaptive on his. If I had not stuck my tongue out initially, he
would not be doing so with such predictability every time he saw me.
Three months later, my wife picked me up after a lecture at a medical
school, Noah in tow. I was still fielding questions, but I scooped up Noah
and held him close while answering. Out of the corner of my eye, I noticed
Noah gazing at me expectantly, flicking his tongue out about every five
seconds. I smiled and stuck my tongue out at Noah mid-question.
Immediately he squealed and started sticking his tongue out with abandon,
every half second or so. I knew exactly what he was doing. Noah made an
observation (Dad and I stick our tongues out at each other), formed a
hypothesis (I bet if I stick my tongue out at Dad, he will stick his tongue
back out at me), created and executed his experiment (I will stick my
tongue out at Dad), and changed his behavior as a result of the evaluation of
his research (sticking his tongue out more frequently).
Nobody taught Noah, or any other baby, how to do this. And it is a
lifelong strategy. You probably did it this morning when you couldn’t find
your glasses, hypothesized they were in the bathroom, and went to look.
From a brain science perspective, we don’t even have a good metaphor to
describe how you know to do that. It is so automatic, you probably had no
idea you were looking at the results of a successful experiment when you
found your glasses lying on a towel.
Noah’s story is just one example of how babies use their precious
preloaded information-gathering strategies to gain knowledge they didn’t
have at birth. We also can see it in broken stuff, disappearing cups and
temper tantrums.
12 months old: Infants analyze how objects act

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Babies younger than a year old will systematically analyze an object
with every sensory weapon at their disposal. They will feel it, kick it, try to
tear it apart, stick it in their ear, stick it in their mouth, give it to you so that
you can stick it in your mouth. They appear to be intensely gathering
information about the properties of the object. Babies methodically do
experiments on the objects to see what else they will do. In our household,
this usually meant breaking stuff.
These object-oriented research projects grow increasingly sophisticated.
In one set of experiments, babies were given a rake, and a toy was placed
nearby. The babies quickly learned to use the rake to get the toy. This is not
exactly a groundbreaking discovery, as every parent knows. After a few
successful attempts, the babies lost interest in the toy. But not in the
experiment. Again and again, they would take the toy and move it to a
different place, then use the rake to grab it. You can almost hear them
exclaiming, “Wow! How does this happen?”
18 months old: Objects still exist if you can’t see them
Little Emily, before 18 months of age, still believes that if an object is
hidden from view, that object has disappeared. She does not have what is
known as “object permanence.” That is about to change. Emily has been
playing with a washcloth and a cup. She covers the cup with the cloth, and
then pauses for a second, a concerned look on her brow. Slowly she pulls
the cloth away from the cup. The cup is still there! She glares for a moment,
then quickly covers it back up. Thirty seconds go by before her hand
tentatively reaches for the cloth. Repeating the experiment, she slowly
removes the cloth. The cup is 
still
there! She squeals with delight. Now
things go quickly. She covers and uncovers the cup again and again,
laughing loudly each time. It is dawning on Emily that the cup has object
permanence: Even if removed from view, it has not disappeared. She will
repeat this experiment for more than half an hour. If you have ever spent
time with an 18-month-old, you know that getting one to concentrate on
anything for 30 minutes is some kind of miracle. Yet it happens, and to
babies at this age all over the world.
Though this may sound like a delightful form of peekaboo, it is actually
an experiment whose failure would have lethal evolutionary consequences.

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Object permanence is an important concept to have if you live in the
savannah. Saber-toothed tigers still exist, for example, even if they
suddenly duck down in the tall grass. Those who didn’t acquire this
knowledge usually were on some predator’s menu.