Flexibility is the ability to adjust your thoughts, actions and feelings to the circumstances you find yourself in. Situations change, and so it's important to be able to adjust and behave in the most functional way to achieve your goals. When you're born, your brain is not finished. Infant brains are born under construction. They're waiting for a set of wiring instructions from the world. If you expose your children to a lot of varying experiences then you're basically wiring your child's brain to function in a flexible way and to learn new things when necessary. If your child's experiences are very restricted then your child will have less flexibility to adjust their actions to the situations that they're in. There's a really well-known demonstration of flexibility called the Stroop test. A sequence of words, such as red, green, yellow, blue but written in different colors. When you present people with a whole list of these, you find that it takes people longer to name the color of the ink, when the word is written in a colour that is different to the actual word. The idea behind that is in order to be able to name the colour requires people to switch between different pieces of information in their mind. In simple terms, what happens is that when they scan the word color, the automatic processes of reading the word interfere with the person's ability to state the color out loud. The more difficult people find this generally the less cognitively flexible they are.