Trickle-down economics - a theory directly associated with "Reaganomics", but still relevant today. The idea consists of deregulation of the economy and of lower tax for the top in order to increase the "size of the pie" so everybody would have a bigger piece, even with a smaller share.
In this small video, Joseph Stiglitz gives an overview of "trickle-down economics" and why it has failed its own promises of raising people's living standard.
This is the short version of a longer video (see here). It consists of good arguments by a distinguished professor. It is relevant for Exploring Economics since it is about a current discussion.