Coming to an individual, what are the factors that influence actions of self interest Basically, individuals are goal oriented, and as such, they depend on their skills and resource to achieve their goals. Also, in order to achieve his goals, an individual may look for information, evaluate alternatives, and choose the ideal option. In the absence of these, there is manipulation due to lack of information and ignorance.
There are also other factors involved in the process of decision making. "The rational ideal not only overstates the purity of information, it also exaggerates the rationality of the people using information. That humans do not make decisions in purely rational fashion is a point that needs no belaboring."  This is what Charles Lindblom has called "the preceptoral system," whereby "a system of social control is exercised by a highly unilateral governmental persuasion addressed not to an elite or to a bureaucracy alone but to an entire population"  "While the individual in the rational ideal is autonomous, free to deliberate and choose on the basis of accurate information, in the preceptoral system the individual is a puppet whose mind has been invaded by others and who acts as though he or she chooses voluntarily but is in fact directed from without." 
The practice of restriction or suppression of information is not only confined to totalitarian regimes, it is also practiced in the highly scientific corridors of medical research, mega business houses, the media, law agencies, political parties, and at the highest levels of the proponents of free society. 
Nonetheless, public-interest is the result of experience and proper understanding of what the problem is and how the solution could be achieved with minimum confusion and confrontation. It involves public debate and perception, and allows for discussion and information based solutions, instead of leaving it to the discretion of a single individual. "The rational ideal, in sum, offers a vision of society where conflict is temporary and unnecessary, where force is replaced by discussion, and where individual actions are
1Policy Paradox, p314.
2Policy Paradox, Chapter 13, page 316.
3Policy Paradox, p308.
4Why Public Ideas Matter Chapter 2, page 31
brought into harmony through the persuasive power of logic and evidence. Government by persuasion brings out the highest human quality - the capacity to deliberate." 
However, the decision making process often tend to be long and tedious on issues related to public interest. That is why sometimes it is felt that that there is the need for some element of totalitarianism in government. That is to say, it is not always necessary for government to be of the totalitarian type in order to use persuasion.
"Let us for the moment, however, not make totalitarian government a necessary condition for indoctrination and so not limit indoctrination to totalitarian regimes by definition. Instead, let us regard it as a relationship in which dominant elites control people's beliefs and