Definition: Openness to experience is one of the "Big Five" personality factors. A person who is high in openness to experience is creative, flexible, curious and adventurous. He enjoys having his mind and senses stimulated, such as by viewing art, listening to new music, sampling exotic cuisine and reading literature and poetry. An open person likes to have variety in his day-to-day life and craves novelty.
On the other hand, a person who is low in openness to experience tends to enjoy following routines, likes predictability and structure and tends not to engage his imagination on a regular basis. His beliefs typically match the status quo and his choices in occupation, apparel and other purchases tend to go along with the mainstream standards.
Most people's personalities fall somewhere between these two extremes.
Openness to experience gradually increases until about 20 years of age. Parents of tweens can build upon this natural increase by encouraging divergent thinking. You might do this by writing poems together or going to an art museum and talking about what you each see in the paintings.
Rathus, PhD, Spencer. Psychology: Concepts and Connections, Brief Version. 8th edition. 2007. Belmont, CA: Thomson, Wadsworth.