This is absolutely not true. There are multiple factors which have been proven to affect an individual's IQ over time- * Schooling, * How stimulating their env

This is absolutely not true. There are multiple factors which have been proven to affect an individual's IQ over time- * Schooling, * How stimulating their environment is, * Nutrition, * Disease (although this is generally towards the negative). All of these can be influenced by behavior- people's eating habits affect their nutrition, and people who seek out intellectual stimulation are more likely to find it than those who don't.