Susan Pinker is a developmental psychologist who believes that social interactions are not only necessary for human happiness, but also could be the key to health and longevity. On the Italian island of Sardinia, there are more centenarians living here than in any other country. According to Susan Pinker, this is not because of the island’s sunny disposition or their low-fat, gluten-free diet — it is due to their emphasis on close personal relationships and face-to-face interactions.