The Roller Coaster Years
After experiencing the ready smiles and relatively easygoing attitudes of baby days, many parents are shocked when behavior markedly deteriorates as tots begin to walk. It is common for them suddenly to resist their parents' requests and directives at every turn. It's not just the newfound freedom that drives the sudden bouts of stubbornness. It's that walking turns the toddlers' world upside down — or vertical, as the case may be. Change, even change for the better, taxes the emotional reserves of human beings of all ages and is therefore stressful.
Shortly after learning to walk, toddlers are likely to:
Repeatedly dissolve into tears over small frustrations
Strike out when they are angry
Be stubborn and uncooperative
Have a hard time falling asleep
Wake up crying during the night
Show other signs of stress, such as more frequent infections
Don't worry that you've created a monster. You can expect the sunnier personality to reappear when the novelty of walking wears off and toddlers have adjusted to the many changes mobility has introduced into their life. Then during the “terrible twos” (or “terrific twos,” depending on your point of view), conflict heats up in earnest as struggles over autonomy take center stage.
But when the terrible twos are successfully negotiated, toddlers trust themselves as well as their parents. At that point, youngsters will still dislike many of their parents' limits and rules. They may fuss some and try to get them to change their minds. But even if they're at a loss to understand the reasons for many of their parents' more disappointing decisions, they comply more often than not.
Experience as Teacher
Between ages one and three toddlers make great strides in mastering their careening emotions. In this case, “familiarity breeds content,” so toddlers encounter fewer new things that inspire fear. They know what to expect and how to behave in many situations, and they have learned to follow most of the family routines and rules. Still, even older toddlers may become upset when confronting events they find especially distressing — for instance, when Mom and Dad leave them with a sitter and walk out the door. If the toddlers have been raised in a secure and stable environment, experience will have taught them that they are not being abandoned. Although youngsters nearing their third birthday still break lots of household rules and resist routines at times, they bump into fewer unexpected no-no's while toddling through the house each day. That alone makes parenting far easier.
Growing Bodies
The increased maturity of the frontal lobes of the brain plays a role in children's ever-improving emotional control, too. These physical changes render older toddlers less impulsive and more able to plan ahead, tolerate frustration, and delay gratification. Further, as youngsters develop physically, their skin becomes somewhat less sensitive, their digestive system works better, and their sleep patterns stabilize. Perhaps hunger pangs don't strike with such intensity at age three as at age one, so a minute spent waiting seems less like a year … and more like only half a year!
Emotional development during the toddler years means that as they approach age three, they shouldn't routinely dissolve into tears while having to wait to have their needs and desires satisfied. Although waiting is still hard for them, they react less intensely to small stresses but still frequently become overwhelmed and remain overly emotional by adult standards.

