Human behavioral characteristics generally derive from human sociability, language and symbol use, and the influence they seek on their own world. These include rationality and irrationality, intellect and emotion, and self-preservation and altruism.
While many animals are sociable, human beings have much more complex social structures, especially as increasing technology over the past 300 years has made it possible for people to communicate across wide distances. In contrast with animals, people use symbol systems, of which language is one, and individual people seek to leave their specific marks on the world through cultural production (i.e., art, music).
The human mind is contradictory in nature, which makes human behavior a complex topic to explore. Although people have sufficient rationality to create a field of study such as psychology, people have difficulty carrying that rationality into other situations such as delaying gratification. Related to this idea is the fact that people are both intellectual and emotional. While human achievement derives from the people's intellectual capacity, still love is necessary for satisfaction with life. Finally, people have the capacity to care about each other and even make great sacrifices for other people. Still, people also can be selfish, power hungry and downright mean to each other.
The challenge of studying the human mind is that those doing the studying also possess the same faculty: They are not able to look at the mind objectively because their conclusions are influenced by their own contradictory psychological characteristics. For this reason, any list of human characteristics cannot be complete. Nevertheless, many scientists studying human behavior have made a monumental effort to get beyond the limitations of their own minds.