Study suggests money can buy happiness â perhaps more than previously thought By Kelly Hayes Does dark chocolate make us happy? A recent study suggests that eating chocolate, especially dark chocolate, is linked to lower odds of depressive symptoms. New research suggests that the relationship between a person’s happiness and their income doesn’t plateau around $75,000 a year, contrary to often-cited past research on the subject. Instead, a study published last month found that emotional well-being continues to increase along with income above that threshold. This includes feeling better day-to-day and being more satisfied with life overall. The research, published in the National Academy of Sciences journal, used data from more than 33,000 working U.S. adults, ages 18 to 65. The participants answered prompts in a smartphone app as part of the research project Track Your Happiness, which included questions like, "How do you feel right now?" and "Overall, how satisfied are you with your life?"