PSYCHOLOGY OF POLITI CAL VIOLENCE 5 of response to frustration. The frustration-angcr-aggression theory is more systematically developed and has sabstantially more empirical support than the other two theories. The most influential formulation of frustration-anger-aggression theory was proposed by Dollard16 and his colleagues at Yale in 1939. The basic postulate is that the occurrence of aggressive behaviour always presupposes the existence of frustration and that the existence of frustration leads to some form of aggression. The primary source of the human capacity for violence appears to be the frustration-aggression mechanism. The anger induced by frustration is a motivating force that disposes man to aggression. If frustrations are sufficiently prolonged or sharply felt, aggression is quite likely to occur.17 So in its most basic and fundamental formulation, the frustration-aggression hypothesis maintains that aggression is the result of frustration. Frustration itself is defined as the thwarting or interference with the attainment of goals, aspirations or expectations, and aggression as behaviour designed to injure, physically or otherwise those toward whom it is directed. The disposition to respond aggressively when frustrated is part of man's biological make-up; there is a biologically inherent tendency in men and animals to attack the frustrating agent.1® Analogous concepts used by contemporary American theorists are too many to be stated here. We can mention only a few. Lerner described the gap between what people want and what thev get as "frustrating" and suggests revolutionary consequences.19 Crozier says that one element common to all rebels is frustration, defined ^as "inability to do something one badly wants to do, through circumstances beyond one's control.9120 Four analogous concepts however are more important and need detailed analysis, i Relative Deprivation Relative deprivation is defined by Ted Robert Gurr as "a perceived discrepancy between men's value expectations and their value capabilities.?9a l Value expectations are the goods and conditions of life to which people believe they are rightfully entitled. Value capabilities are the goods and conditions they think they are capable of/attaining and maintaining, given the social means available to them. Societal conditions that increase the average level or intensity of expectations without increasing capabilities increase the intensity of discontent. Societal conditions that decrease man's average value positions without decreasing their value expectations similarly increase deprivation, hence the intensity of dis-coment.2 2 The emphasis of the hypothesis is on the perception of deprivation people may be subjectively deprived of, with reference to their expectation even though an objective observer might not judge them to be in want. Similarly the existence of what the observer judges to be abject poverty or "absolute deprivation" is not necessarily thought to be unjust or irremediable by those who experience it.28 Gurr^s hypothesis is that ihe potential for collective violence varies