“…(The literature on this topic is quite large and it is not the intention to cover the whole range here. For further references see for example Deutsch (1953Deutsch ( , 1961, Lerner (1958), Emerson (1960), McClelland (1961), Apter (1965), Eisenstadt (1966), Black (1967) and Moore (1967).) As was implied at the beginning of this section, the concept is very wide and therefore vague.…”