Between 1820 and 1870, middle-class Americans became convinced of the role nonhuman animals could play in socializing children. Companion animals in and around the household were the medium for training children into self-consciousness about, and abhorrence of, causing pain to other creatures including, ultimately, other people. In an age where the formation of character was perceived as an act of conscious choice and self-control, middle-class Americans understood cruelty to animals as a problem both of individual or familial deficiency and of good and evil. Training children to be self-conscious about kindness became an important task of parenting. Domestic advisors also argued that learning kindness was critical for boys who were developmentally prone to cruelty and whose youthful cruelty had implications both for the future of family life and for the body politic. The practice of pet keeping, where children became stewards of companion animals who were then able to teach young humans such virtues as gratitude and fidelity, became a socially meaningful act.