Piaget found that younger children would randomly change variables without thinking things through, while adolescents capable of formal operations would systematically change one variable at a time to see how it affected the swing speed of the pendulum, much in the same way that Kelly and her friends are experimenting with what captures Jordan's attention.Adolescence is the period of life between childhood and adulthood.
The idea that the brain is somehow fixed in early childhood, which was an idea that was very strongly believed up until fairly recently, is completely wrong.
There's no evidence that the brain is somehow set and can't change after early childhood.
How could Kelly figure out what had caught Jordan's attention? She would keep her hair the way it was on the day he said hi, but change her outfit back to one of her old ones. If he said hi with the old outfit and no encouragement, then it was her hair.
And if he didn't say hi, then on the next day, Kelly would put her hair back to the way it was and wear her old clothes and smile at Jordan.
That is the hallmark of the formal operational period of development, according to Piaget.
Though mental manipulations are the hallmark of formal operations, they aren't the only way that thinking changes in adolescence.
Now she can picture them in her head to figure out that Gene is taller than Mia.
To solve that problem, Kelly has had to imagine the world and do some mental manipulation.
Many changes occur during this time, including cognitive development.
Psychologist Jean Piaget called the cognitive development changes during adolescence the formal operations stage, during which adolescents become adept at mentally manipulating the world around them and systematically manipulating variables during scientific experimentation.