Identifiable Victim Effect
The identifiable victim effect is the human tendency to feel compassion and be more likely to help an individual victim of a crime or tragedy over a large, undefined group of people who experienced the same event. This is why charity infomercials and fundraisers will often have a single child, animal, or victim as a focus for the fund-raising attempt rather than a large group who may become essentially faceless and nameless when presented as a large group.
One theory for this effect suggests that we can more easily identify with an individual victim therefore making us able to relate to them and feel more compassion. This is especially true if they appear particularly attractive or vulnerable (note how many charities uses cute children or adorable animals to represent them). There are other possible aspects to this cognitive bias. Research also has shown we are more likely to feel sympathy and assign less blame to individuals who are similar to us. Another theory suggests that by having one identified victim we perceive that we are more likely to be able to help than with a large, ill defined grouping of people. Often times this quote attributed to Josef Stalin (quoted by Nisbett and Ross, 1980) is used to describe the identifiable victim effect: "The death of a single Russian soldier is a tragedy. A million deaths is a statistic."