Several different theories have been developed to explain the existence of, and the functioning of, international institutions. One school of thought sees such institutions as growing naturally out of the demands of increased economic interdependence. The fact that countries are interacting more frequently with each other creates a demand for simplifying procedures as manifested in rules, procedures, and dispute settlement mechanisms. According to this view of international institutions, the greater the degree of economic interdependence, the greater will be the need for, and the demand for, institutions to facilitate cooperation (Keohane 1983). The institutions can be particularly important to the weaker states in the relationship by providing them with "voice opportunities" to make their views known and to give these views some effect (Grieco 1994).