According to research by Robert Hodge and David Tripp (1986), the characteristic of television violence that has the most significant effect on children's behavior is the:

context within which the violence is portrayed

Explanation:

Robert Hodge and David Tripp are two famous child psychologist who worked on the the effect of the television violence shown on the children's behavior.

According to them, they have found out that children while watching television interprets the material of the show in the framework of their own lives. The children's psychology relates the context of the show where the violence is being portrayed to their own life.

Hence the answer is - --

"context within which the violence is portrayed".