People with happy brains have their parents to thank, to a certain extent, not only for happy genes, but also for loving childhoods. Studies have shown that angry or critical parents can actually alter a child’s happiness level until it’s set around age 16.
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Scientists have known for decades that a large part of our temperament is genetically pre-determined; by studying the personalities of identical twins they’ve found that about 50 percent of our happiness — or unhappiness — can be traced to our genes. Adding the 40 percent that we can control with our daily thoughts and actions still leaves about 10 percent unaccounted for. This remaining 10 percent is related to our life circumstances, such as where we live, how much money we have, our marital status, and how we look.