This is a useful article found on the Psychology Today website, offering a description, accessible to scientists and laypersons alike, of what happens in the human brain, as positive thoughts are experienced.
Samantha Smithstein, Psy.D., offers the idea that being thankful is not just part of a holiday, it's good for our mental health. Her blog, on the Psychology Today website, briefly explores our human tendency to focus on negative thoughts and the benefit of working to increase positive thoughts, as well as several practical methods for application in our daily life.
A study by Kamal Chopra examines the impact of teaching first grade students to identify and reframe negative self-talk into positive self-talk. After a year-long series of lessons, the children participated in a qualitative interview, and Chopra found the children had developed an empowering life skill, the study demonstrated that even very young students are in control of themselves by consciously feeding their minds with positive empowering self-talk.