Images pecked in stone hundreds to thousands of years ago could be for religious reasons, to mark territories or simple doodles such as those still made today by children and adults. That is according to Dr. Ekkehart Malotki, a preeminent researcher into the history of rock art. "Creating art is a distinct piece of our biological make-up," he told about 50 people Saturday during his lecture at Deer Valley Rock Art Center. "It is an instinct." Malotki, a professor emeritus of languages at Northern Arizona University, said no one would ever know the true meaning of images pecked or painted...