Max Weber and some schools of modernization theory suggest that cultural values could affect economic success. However, researchers have gathered evidence that suggest that values are not as deeply ingrained and that changing economic opportunities explain most of the movement into and out of poverty, as opposed to shifts in values. Studies have shown that poverty changes the personalities of children who live in it. The Great Smoky Mountains Study was a ten-year study that was able to demonstrate this. During the study, about one-quarter of the families saw a dramatic and unexpected increase in income. The study showed that among these children, instances of behavioral and emotional disorders decreased, and conscientiousness and agreeableness increased.