When people look at people, they assess them, and there there exist to the person who is looking easily available visual cues that provide a heuristic for assessments (Sugiyama 2016). Physical attractiveness is assessed within milliseconds of seeing a new face (Willis and Todorov 2006) and is a reliable indicator of genetic quality and health (Little 2014; Re and Rule 2016).

A heuristic technique (/hjʊəˈrɪstɪk/; Ancient Greek: εὑρίσκω, "find" or "discover"), often called simply aheuristic, is any approach to problem solving or self-discovery that employs a practical method, not guaranteed to be optimal, perfect, logical, or rational, but instead sufficient for reaching an immediate goal.