The researchers also examined 133 jury cases between 2000 and 2009 involving exposure to toxic chemicals. They found as the number of people that were effected by the toxic chemicals increased, the amount of total damages the person responsible was asked to pay decreased.
Now those are some perverse incentives. If you know that you have harmed a few people, and you know that you will be caught eventually and involved in a lawsuit, then you should try to harm as many other people as possible. After all, a jury will punish you more for poisoning 5 people than for poisoning 500.
Our instincts and emotions simply do not know how to think about any number of people greater than 150. Our brains only know how to operate in the context of a small tribe, unless we properly train ourselves to avoid these kinds of cognitive biases.