New research from the University of Sussex has revealed the biological limits to human compassion and empathy. The study found a stark contrast between how the brain processes information about risk to human lives and information about risk to money and could help explain why people can struggle to respond emotionally to large-scale humanitarian disasters.
Published in Social Cognitive and Affective Neuroscience, the study by Sussex researchers Dr Dan Campbell-Meiklejohn and Dr Jo Cutler used MRI scans to examine how people process information about real life-and-death events in the brain. The team found that neural responses were surprisingly low for large numbers of lives at risk and for lives lost overseas.
Their findings shed new light on two longstanding challenges in humanitarian response: our tendency to tune out as a disaster grows larger, and to prioritise local crises over those further away.
Dr Dan Campbell-Meiklejohn, Associate Professor of Psychology and Director of the Social Motivation Lab at the University of Sussex, said:
"The world is facing more life-threatening problems that require a global response. Our findings suggest that our brain’s processing of people at risk can be lower if those lives are far away or in greater numbers. Those biases may have grown out of evolution in small groups facing nearby threats or perhaps from how our brains are shaped by the media we experience. Whatever the cause, living up to values that all lives matter equally may require all of us, especially policy makers and communicators, to work together to overcome these limits and save more lives both at home and abroad."
The researchers scanned the brains of British participants as they read 200 news headlines describing real threats to life that happened, ranging from a single person to tens of thousands of people, either in the UK or across 56 other countries. Participants then learned whether those individuals survived or died.
In addition, the participants were given a large number of entries to a genuine prize draw with a cash reward. Throughout the experiment, they were then told that some of their entries were also at risk, and that they could lose anywhere between one to a thousand of their chances to win the money. Later, they were told whether those entries had in fact been lost or were safe. Their brain responses to these financial risks and losses were measured, just like they were for human lives
This uncovered several insights into how the brain responds to human suffering: revealing how people become less responsive as the number of victims grows and how deaths abroad are processed differently from those at home.
The findings could help policymakers and humanitarian organisations develop more effective ways of communicating global crises and encouraging action:
A collapse of response as the number of lives at risk increases: When tracking financial risks, brain activity scales up naturally as the amount of money increases. But with human lives, the opposite happens: brain activity broadly decreases as the number of people at risk grows. This happens no matter where the lives are located in the world.
A unique pattern for overseas lives: Unlike individual lives at risk at home, single lives at risk abroad generate a very low response. The response does go up for mid-range numbers but then collapses for the largest numbers of victims. This creates a characteristic ‘inverted U’ pattern of response across the number of lives at risk in countries abroad.
Empathy regions react differently to risks compared to deaths – but only in our home country: Brain activity shows a heightened response when local people die compared to when they survive. Crucially, these same regions show no measurable distinction between survival and death if it occurs abroad.
The researchers caution that brain scans reveal patterns of neural activity rather than a single explanation for human behaviour. Follow-up responses from participants suggested that if they were biased toward local events, it was because these would be more likely to affect them or people they know, indicating that self-protection may play a role alongside differences of empathy.
Social Cognitive and Affective Neuroscience
Experimental study
People
Diminished Neural Responses for Greater Numbers of Lives at Risk and Lives Lost in Foreign Countries
28-Jul-2026