I think, there can be the basement of pressing. As an example here could be social networks, where people share their life to others, and other had to be better than first one. So there can be the pressure of economical situation of some persons, and also the pressure of lower self-esteem.
Slave traders viewed humans lives as dogs. Because slave traders only wanted humans to work for them and do there dirty work. They did not think anything of there value of life.
