The brain grows
dramatically through the second year of life. Around 12 months, toddlers
develop a new ability to remember experiences that occurred a few hours or even
a day earlier. Toddlers often demonstrate this new ability by repeating a
recalled experience, such as throwing a ball or stacking blocks, at a later
time. Changes in the brain allow a toddler between 18 and 24 months of age to
think in more complex ways, such as recalling events that occurred days
earlier. The older toddler begins playing pretend, such as giving a teddy bear
a "drink" from a cup or "talking" on the phone. These toddlers are also
beginning to understand symbols (for example, that words can stand for
objects).
Toddlers also begin to see connections between events. For example,
when they open a music box, they know they will hear a song, or when they throw
a ball, they know it bounces. They'll probably throw their dolls, food, and
many other objects to see if they'll bounce too.
At 18 months, toddlers have developed a greater understanding of the
world outside of home. Toddlers begin to develop a sense of self, the ability
to see themselves as separate from others. They can now imagine a threat and
often go through a period of clinging to parents and being fearful of
strangers.