Two social psychological theories are central in establishing how humans perceive machines. Therefore, they form a foundation for the machine penalty. First, Computers Are Social Actors shows that, given social cues, we tend to respond to machines in social ways, such as treating them politely or deferring more to their specialized expertise. This is primarily due to automatic or mindless reactions to computers, wherein we respond according to social heuristics to machine’s social behaviors and cues. Second, anthropomorphism involves perceiving machines as not just social, but also having human characteristics and motivations. We anthropomorphize to better explain unpredictable machine behavior, to relationally connect to machines, and by projecting our internal self-motivations onto machines. These theories establish the social and human nature of perceiving machines and provide the groundwork for the machine penalty’s explicit comparison between AI and humans.