In June 2023, two tragedies took place at sea, drawing starkly different reactions. In the first instance, an estimated 500 migrants from Syria, Pakistan, Egypt and the Palestinian territories died after a dangerously overcrowded fishing trawler sank near the Greek coast, receiving little to no assistance from the coast guard. In the second, an experimental submersible craft carrying five people on a tourist expedition to the wreck of the Titanic disappeared and later imploded underwater, leading to a multimillion-dollar rescue operation that involved several countries and private parties. Because these events happened just days apart, many were outraged: Why did five deaths seem to matter more than 500?

In English, this is known as the hierarchy of death. The French have a grimmer—and perhaps more telling—expression for it: la loi du mort-kilomètre, literally “the rule of death per kilometer,” which states that the public, and by extension the media, tend to feel more concern over the death of one person close to home (either literally or metaphorically) than over the deaths of thousands of people abroad. 

Many criticize the cynicism of such an expression, especially as it is used to justify disproportionate interest in domestic matters over international ones. And yet it is undeniable that there is only so much suffering one can empathize with day to day. Human compassion fades not only with distance but also—as the number of people whose suffering we’re exposed to rises—with a phenomenon known as “psychic numbing.” Health care professionals, aid workers and journalists often experience a related condition called compassion fatigue, an emotional burnout characterized by physical and mental exhaustion. 

“Compassion draws on mental resources and given that our mental resources are finite, we have a finite capacity for it,” explains Adam Waytz, a psychologist and professor at Northwestern University. And because our tendency is to direct our empathy toward those we feel closer to, “we might fail to properly acknowledge the suffering of others"—to be unfair to groups we consider different from ourselves, say, or unethically biased toward those we favor.