Development of learners' critical thinking skills is an integral part of the modernization of current education system on the whole and foreign language learning in particular.

In accordance with the requirements of Common European Framework of Reference for Language  Learning and Teaching (CEFR) it becomes obvious the necessity of development of analytical and evaluative skills among high school students. In addition to spontaneity and fluency,  students should develop  skills of argumenting their personal opinion, as well as analyzing positive and negative aspects of  people opinions. As emphasized in the European requirements for language proficiency, high school students should be able to produce clear, detailed reports on a variety of subjects and express their viewpoint on a required topic, demonstrate advantages and disadvantages of various opinions, build a reasoned statement [1].

The issue of individual development and  formation, possessing certain qualities of thinking ability, has become a vital problem at the present time. It is caused by the evolutional development of the country as a democratic society. For the formation of free creative citizens of such a society, it is important to develop their critical thinking skills. In the foreign language classroom learners' critical thinking skills formation is developed within  the use of  such speech activities as reading, writing and speaking [2].

There are a variety of opinions and assessments about the concept of "critical thinking". On the one hand, it is associated with something negative, as it implies dispute, conflict; on the other hand, it combines the concepts of "critical", "analytical", "logical", "creative" thinking, etc. Although the term of "critical thinking" is known for a very long time from the work of famous psychologists such as Piaget [3], Vygotsky [4], etc., in the educational process it occurred recently.

J. A. Brouse and D. Wood define critical thinking as a reasonable reflective thinking, focused on solution of  what to believe in and what to do. [5] Critical thinkers try to be objective, logical, and understand other points of view. Critical thinking, in their opinion is a search for common sense and the ability to refuse of own prejudices. Students with critical thinking skills are capable to put forward new ideas and see new opportunities, which are very important  in solution of problems.

D.Kluster argues that critical thinking begins with asking questions and clarifying the problems that could be solved [6]. He connects the definition of the concept of "critical thinking" with the problem solving and the ways of its solution. In our opinion, critical thinking is an ability to analyze incoming information and treat  it both from positive and negative sides without any subjective intervention.

D. Halpern defines the concept of critical thinking in the research "Psychology of critical thinking" as a directed way of thinking, being logical, and action oriented, it is characterised by the use of cognitive skills and strategies that increase the probability of obtaining the desired result [7].

  D.Halpern treats critical thinking as an equivalent to creative thinking.  However, it is considered by some researchers that there is a difference between them and they are not identical [8, 9]. Critical thinking can be characterized as an open way thinking, it does not accept any dogmas, and it is developing by applying new information on the personal experience of life. Critical thinking is the starting point for the development of creative thinking, they are being evolved in the synthesis, interdependently.

It is natural that human mind development is specific for every individual, so we believe that human's ability to think critically is not developed at one and the same level in every person, and for this purpose it should be improved. But the question is at what age the students are able to think critically? Piaget, J. wrote that the stage when the best conditions for the development of critical thinking appears is the age of  14-16, but it does not mean that this ability is equally developed in everybody.

To develop learners' ability to think critically, it is important for them to possess a number of qualities, among which D.Halpern highlights following:

1. Ability for planning. Human thoughts often occur randomly. It is important to organize them, build a sequence of presentation. Well-ordered thoughts are the sign of selfconfidence.

2. Flexibility. If the students are not ready to accept the ideas of others, they can never become  generators of their own ideas and thoughts. Flexibility allows them  not  to make spontaneous  judgment until the students  do not have the wide variety of information.

3. Perseverance. Facing difficult problems, we often postpone its decision for later time. Generating persistence in suspense mind, the student will manage to achieve much better results in learning.

4. Willingness to correct one's own mistakes. Critically thinking person would not justify his wrong decisions, he will draw conclusions, taking into account his mistakes for further cognitive improvement.

5. Awareness. This is a very important quality, that requires the ability to observe oneself in the process of mental activity, monitoring the progress of reasoning.

6. Search for compromise solutions. It is important for the decisions to be perceived by other people, otherwise they will remain at the level of statements [7].

There are also other criteria, selected by researchers for identifying the students' skills of critical thinking:

1. Ability to ask essential questions on the studied  material;

2. Ability to assess and put forward one's own arguments;

3. Ability if necessary to admit lack of information or understanding ;

4. Desire to explore the views or postulates, contained in the source, and compare them with the facts;

5. Possess certain set of criteria for analyzing ideas;

6. Ability to carefully listen to other students and then express his own point of view;

7. Ability to search for arguments for supporting one's own ideas;

8. The skill of searching for critical information as an integral part of the process of cognition;

9. Ability to draw logical conclusions based on the information got.

Indeed, understanding the differences between the fact and personal opinion, the ability to make inferences on the basis of the information is necessary and significant skill. American researcher D.Ellis in his manual "Active thinker" focused on the fact that students, possessing the critical thinking skills are able to understand the difference between fact and opinion; ask questions, make detailed interest observations [10].

In conclusion, it should be noted that the critical thinking, being a natural way of  interaction with ideas and information  enables modern educational system to rise on a new level.

At the present time the problem of selecting information has become a vital problem. It is important not only to possess it, but also to evaluate critically, interpret, process and apply in real-life situations. Getting new information, students should be able to analyze it from different points of view, draw conclusions about its value and accuracy.

In language teaching and learning process, it is necessary to use approaches, technologies and techniques, which allow the students to be aware of the issues discussed in the framework of intercultural communication, search and find their own problem solutions, rather than proposed by a teacher.

Modern life sets new priorities for independent cognitive development of the students: it is the ability not only to know the facts, but use them appropriately; it is the ability to receive and model information rather than possess it; it is a creative, fruitful work and cooperation rather than consumerism. Thus, in our opinion, the development of students' critical thinking skills creates better opportunities for their personal growth, i.e. such work is primarily addressed to the child's individuality, as well as to the improvement of his skills to think critically and find his own way for problem solution.

2. Vlasova EB Critical thinking in teaching English // Foreign languages at school. 2008. - № 8. - P.24.

3. Piaget, J. Genetic aspects of language and thought // Psycholinguistics. - M., 1984.

4. Vygotsky, LS Psychology of Human Development. - M .: Publishing House of meaning; Exmo, 2005.

5. Brouse JA, Wood D. Environmental education at schools: Translation from English. NAAEE, 1994

6. David Klooster // Critical thinking and new literacy. M .: TSGL, 2005, P.5

7. D. Halpern Psychology of critical thinking. - Peter, 2000.

8. Bolkov EV Development of critical thinking. M., 2004.

9. Maklakov AG General Psychology - SPb: Peter, 2001 - 592 pp

10. Ellis D. An Active Thinker. - New York: Pantheon Books, 1999.