In case that a nudge is intended to act on the altruism/ethical norms/moral considerations of an individual, its mechanism is quite different from that of the nudges intended correct a cognitive bias/failure of consideration.
In the latter case, the nudge used the bounded rationality of the individuals to change their decision, and while it might change the perceived cost of taking an action, it does not change the utility of the choice as such (for example, default options or availability of certain choices).
In the case of the moral/ethical nudges however, the policy-maker who is intending to invoke the moral norms relating to the decision with the nudge is intending to change people’s utility of the choice they make - the nudge is effective if it encourages people to build into their utility functions the moral considerations relating to the decisions.
Does this distinction between the two types of nudges have any implications for their legitimacy, and can we say that the type of moral/ethical nudges is more apparent in pro-social nudging while the nudges intending to correct cognitive biases are more frequent in nudging with a paternalistic motive (furthering the individual’s own good?)