Smiling and laughter can positively impact happiness and social interactions. The limbic system in the brain, including the amygdala, thalamus, hypothalamus, and hippocampus, is associated with feelings of happiness. Evolutionary psychologists believe happiness helped with survival by enhancing traits like social acceptance and mating. Physically, smiling and laughter can increase energy and improve response to illness. Mentally, they promote emotional stability and coping. Socially, smiling and laughter are linked to increased workplace and relationship success as well as more friendships. Both smiling and laughter are universally recognized expressions of positivity that can transmit happiness to others and improve mood.