The chapter focuses on the evolutionary explanation of yawning, crying, tears, and two types of depression. Individual yawning, characteristic of many animals, becomes contagious in human communities. This acquired structure, realized by “mirror neurons,” probably facilitated hominins’ collective bedtime. Crying is not a “useless” side effect, as Darwin believed. Infant crying, similar to the cries for help of infants in other mammals, was a kind of “evolutionary prototype” for adult crying. Self-domestication, which led to pedomorphism (the preservation of childlike traits in adults), made adult hominins more prone to cry in situations of helplessness. Initially, crying was a collective behavior associated with the formation of shared intentionality, the growth of intragroup solidarity, and mutual empathy. The group responded to overwhelming frustration and stress with crying when all attempts at remedy failed. Communal sobbing in response to insurmountable loss helped reduce stress, restore an acceptable emotional state, and strengthen the social cohesion of the group, which provided advantages in the struggle for survival. The author analyzes the social norms governing crying and the mechanisms of its inhibition. Tears, originally adapted to wash foreign bodies out of the eyes, became associated with crying as a result of practices to help children who cried in the face of such discomfort. Depression is not a providing structure, but a painful breakdown of complex mental processes. There is an analogy between depressive states and the presumed consequences of severe ostracism in hominin groups. Prolonged experiences of loneliness and rejection could lead to profound mental disturbances manifested in stupor, apathy, refusal to eat, and self-care. Severe depression caused by the loss of a loved one can result in a kind of “self-ostracization,” in which a person unconsciously rejects the world he or she associates with the unbearable pain of loss. The standards and competition of modern societies may produce another type of depression, one associated with social frustration. The mismatch between high “bars” of success and a person’s abilities leads to chronic failure and loss of self-esteem, which can lead to a depressive state. The author proposes hypotheses to test the relationships between crying, solidarity, stress, and social support.