Moral decision-making ‘on the fly’

Over a century of research has focused on the consistency and inconsistency of
moral decision preferences. We propose that shifting between moral principles is
an adaptive strategy and that it is reinforcement learning that underlies its flexible
nature. Decision-makers’ psychological concept of morality is continually under
construction (on the fly); consequently, moral flexibility is an adaptive and
advantageous moral strategy based on learning, informed by changes in moral
rules and specific moral contexts. Accordingly, in two experiments we developed
and employed a two-stage supervised learning task, where participants learned
novel moral rules based on corrective feedback of their moral decisions. Our
original method and empirical findings demonstrate that participants learn new
moral rules, transfer these rules to tasks where no feedback is provided. However,
we found that participants make decisions based on the principle of maximizing
utility rather than a learned rule when the rule conflicts with this principle. In light
of our proposal and findings that decision-makers’ psychological concept of
morality is continually under construction, moral-decision-making researchers
should integrate learning into their respective models and predictions.