Oxytocin and vasopressin are two neuropeptides that perform a wide range of important functions. For example, vasopressin is involved with kidney function. However, they are best known within the field of psychology for their involvement in social behavior. Oxytocin has been linked to childbearing and lactation and both oxytocin and vasopressin have been linked to parenting behavior as well as to sexual orgasm and the emotional connection formed during sexual activity. A famous series of studies on the social behavior of the vole (see Sidebar) suggests that these chemicals are less related to sexual behavior per se than to the formation of emotional bonds.