Using data from three countries that differ economically, culturally, and geographically, this study examines the role of Prospect Theory's reflection effect, a psychological factor, in combination with Uncertainty Avoidance (UA), a cultural factor, on the choice of mortgage products. Experiments were conducted using business professionals in the United States, Germany, and Japan. The results suggest that risk-averse people tend to become more risk seeking, leaning more toward adjustable-rate mortgages (ARMs) when choosing a mortgage type, and that this psychological effect may underlie the mortgage choices of people who tend to choose ARMs, even across countries with different cultures.