But Professor Gaechter says his team's theory was that punishment has only low costs because it needs to be used rarely and works as a threat.

VOA: special.2009.03.03

Under his theory, businesses act as structures for conflict resolution.

VOA: special.2009.10.16

That theory is known as evolution through natural selection.

VOA: special.2009.02.25

Under this theory, the superego acts as a restraint.

VOA: special.2010.04.13

As a result,he was almost upstaged by a younger colleague, Alfred Russell Wallace, who developed the theory of evolution through his own research.

VOA: standard.2009.11.25

Williamson developed a theory where business firms can serve as structures to resolve conflicts.

VOA: standard.2009.10.12