Barbara Fredickson proposed the broaden and build theory in which she posits “that these positive emotions broaden an individual’s momentary thought–action repertoire: joy sparks the urge to play, interest sparks the urge to explore, contentment sparks the urge to savour and integrate, and love sparks a recurring cycle of each of these urges within safe, close relationships.”

Her own experiments showed the powerful physiological response as illustrated below:

Now, research is showing that positive emotions impact on genetic level. When DNA was physically separated from the subject and the subject was then exposed to either Positive or Negative emotions, the DNA responded as well. With positive emotions, the DNA strands expanded. With negative emotions it contracts.