When decisions about intervention to protect lives move outside individual choices and to the level of governments, we see similarly problematic choices being made. When we look at mass atrocities and genocides in particular, we see mass intervention and cooperative government action in some cases, while other situations, sometimes with greater numbers of imperiled lives, are ignored. This can be the case even when decisions not to intervene appear to violate our strongly held values for protecting life. Why does this occur?
The idea of prominence is that some social values carry more weight than others when choices are made, despite holding less intrinsic value outside the realm of choice or decision.
In other words, while we claim that humanitarian goals and the elimination of atrocities and genocides is key to our national identities and personal values, decisions need to be justified and "prominent" objectives, i.e. objectives that are more readily justified, take precedent over other objectives even when we express high importance in the latter. As a result of prominence bias, decisions that protect national security or our perceived economic interests will consistently outweigh needs such as environmental protections or the protection of large numbers of statistical lives.
This idea also operates on the level of individuals making decisions based on needs that seem more important in the moment than our intrinsic values. For example: someone who believes environmental protection is important and burning fossil fuels is quite bad for the environment may choose to fly cross country to attend a meeting in person rather than to attend virtually.
"When (In)Action Speaks Louder Than Words: Confronting the Collapse of Humanitarian Values in Foreign Policy Decisions" by Paul Slovic. University of Illinois Law Review, 2015.