A new Cornell University study suggests if you want your children to grow up to actively care about the environment, give them plenty of time to play in the "wild" before they're 11 years old.

Environmental psychologist Nancy Wells says, "Although domesticated nature activities -- caring for plants and gardens -- also have a positive relationship to adult environment attitudes, their effects aren't as strong as participating in such wild nature activities as camping, playing in the woods, hiking, walking, fishing and hunting."

Wells continues, "Our study indicates that participating in wild nature activities before age 11 is a particularly potent pathway toward shaping both environmental attitudes and behaviors in adulthood."

Wells' previous studies have found that nature around a home can help protect children against life stress and boost children's cognitive functioning.