**1. Introduction**

Information-psychological impact (IPI) is the informational influence on people's minds, which alters their perception of the reality, behavioural functions and, in some cases, even the functioning of their inner organs and body systems [1–3]. Information-psychological impact (IPI) may affect individuals, groups of people, communities and the whole society. IPI can be either positive or negative, depending on the intended purpose. Positive IPI is used for medical treatment purposes, rehabilitation, improvement of behavioural patterns and creative purposes. It can also be used to unite people for a good cause. Negative IPI is used for manipulating—directly or indirectly—individuals, groups of people or the whole society into actions that violate either their own interests or interests of others. Negative IPI may cause emotional, psychological and social tensions, deterioration of moral standards and behavioural norms, as well as moral and political disorientation. This, in turn, leads to dramatic changes in individual, group and public

conscience and alterations in the moral, political, social and psychological environment within the society [1–3].

Information-psychological impact is implemented by means of various tools and techniques. At the moment, negative information-psychological impacts are more common. They influence individuals, groups of people or the society by means of telecommunication systems, mass media and social networks. Negative IPIs are used to control the society, force certain opinions on various issues, recruit members to religious cults and terrorist groups and to alter people's mental state. Among the examples of such IPIs are colour revolutions, the so-called "death groups" on social networking sites, as well as active recruitment campaigns to terrorist groups, which are based on films or video games aimed primarily at young people.

subject are presented as vector *yt* and change under the influence of other

ferromagnetism, Ising model is often used to verify the results of numerical modelling. When studying the diffusion of IPI in social networks, the model helps to describe the changes in the behaviour of a large social group caused by the nearest neighbours. The influence of the nearest neighbours plays a key role, and the willingness of the group to accept a new idea serves as the

4. Influence models based on Markov chains. Such models employ corresponding mathematical tools to represent the activities of every subject and the group as a whole. They are used to analyse social dynamics and determine the patterns of the group behaviour. The authors [22–24] consider the similarity of opinions of the subject, the authors [7, 24] focus on the time over which the opinions become similar, and the authors [7, 25] study the conditions under

All the above-mentioned models represent the rules of interaction between the subjects or groups of subjects. However, they either do not at all represent the specifics and characteristics of the network influence and the interaction process or

When a social network is considered as a set of agents [4, 26–28], we assume

therefore necessary to determine a small group of agents with the maximal level of influence, that is, to solve the influence maximisation problem [4, 10, 29]. These agents can be used as key nods for influencing other subjects of the social network

that every agent has a certain degree of influence on the other agents. It is

or to monitor the social network in order to reveal the presence of IPI. The influence maximisation problem has been considered in papers focusing on the

• Viral marketing [29], where a social network is represented by a Markov chain with each agent A having his own value that depends on the profit from

• Influence maximisation in the models of innovations' diffusion [10]. They include a set of active agents, and at a certain point in time, a new active agent

• Voting process modelling [9], where every agent can, at any stage, change his opinion by accidentally voting for one of his neighbours and adapting their opinion. The agent is more likely to adapt the opinion supported by the

Besides analysing the influence, management and confrontation, there is also a problem of diffusion of information-psychological impact in the information space [5]. Information may spread in the following directions [5, 30]: from a subject to another subject, from a subject to a group, from the information production centre

The authors [5, 26–28, 31] suggest a multi-agent model of information diffusion. The model takes into account the growth of the number of agents over time. Agents

.

subjects according to the so-called influence matrix *<sup>W</sup>*: *yt*þ<sup>1</sup> <sup>¼</sup> *Wyt*

3. Ising models [20, 21]. Invented for studying the phenomenon of

*Modelling the Information-Psychological Impact in Social Networks*

analogue of the temperature.

*DOI: http://dx.doi.org/10.5772/intechopen.88252*

do this inadequately.

following issues.

which a uniform final opinion is formed.

sales to other agents influenced by agent A.

majority of his neighbours.

to an individual subject or a group.

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can activate his neighbours with a set probability.

It is thus very important to model IPIs in social networks in order to analyse and select the most effective methods of using positive IPIs and combating negative IPIs [1, 2, 4].
