Through her research, Fredrickson found that vagal tone can be strengthened like a muscle. Study participants practiced a form of Buddhist meditation called metta, or loving-kindness, cultivating benevolent feelings of goodwill and compassion towards themselves and to others. The result was increased vagal tone, as well as increased positive emotions and social connectedness. Further research by Fredrickson and her colleagues uncovered how “people’s perceptions of their positive social connections with others accounted for the causal link between positive emotions and improved vagal tone.”