We report results from a framed field experiment with a realistic retirement savings simulation to examine two factors in socially responsible investment (SRI) decisions: characteristics of investors and the investment choice architecture. We find that default options, age and values are significant explanators while infographics, gender, education and income are not. Further, repeated decisions affect SRI negatively through donor fatigue and positively through windfall gains. Our results suggest SRI is significantly limited by the non-ethical default options pension providers commonly set. Conversely there is scope for nudging pension savers towards socially responsible investments using defaults.