Many studies show that De Bono's Six Thinking Hats training method guides people to improve their critical thinking skills. Therefore, the current research was carried out in order to "investigate the effectiveness of the six thinking hats technique on the critical thinking skills of fourth grade elementary students in the three dimensions of creativity, cognitive maturity and mental engagement"; In addition, the effect of this method on the critical thinking of three categories of students (strong-medium-weak) was investigated. One school was selected from the population of fourth grade elementary school girls in district 15 of Tehran, and two fourth grade classes were randomly assigned to the experimental and control groups. The research method was quasi-experimental with pre-test and post-test. Ricketts (2003) critical thinking questionnaire was used to measure students' critical thinking. Educational intervention in the form of six thinking hats technique was carried out in 12 60-minute training sessions for the experimental group. The results of the multivariate covariance analysis (MANCOVA) test showed that the six thinking hats have an effect on improving students' critical thinking in the three dimensions of creativity, cognitive maturity, and mental engagement. There is no significant difference between strong and average students as well as average and weak students. But there is a significant difference between strong and weak students. In general, it can be said that the technique of six thinking hats improves critical thinking skills in the three dimensions of creativity, cognitive maturity, and mental engagement according to students' academic performance.
Keywords: critical thinking, six hats of thinking, effectiveness, academic performance, fourth grade.
 
 
Introduction
Nowadays, the main goal of primary education is not only teaching reading, writing and the courses defined in the educational system, but teaching how to use thinking skills, including creative and critical thinking, in facing the rapid changes of the modern world, is necessary to cultivate lifelong learners. Critical thinking is a cognitive process that combines the ability to interpret, analyze, and evaluate information, arguments, and experiences with a set of attitudes, skills, and abilities to guide thoughts, beliefs, and actions. Teaching students critical thinking has been developed by teachers around the world in different ways. The six thinking hats concept presented by De Bono (1995) is one example that has inspired a wide range of critical and creative thinking training programs. The Six Thinking Hats technique is an attractive strategy that forces students to think and discuss a problem from different perspectives and includes thinking processes to solve problems, decision-making, and mental processes necessary to benefit from education, such as comparison, evaluation, justification, and inference. The characteristic of each of the thinking hats is as follows: white hat thinking (facts): white hat includes passive issues and forms. With this hat, facts are explored in the form of facts and statistics without any judgment. Red hat thinking (emotions): The red hat emphasizes emotional insights, sudden discoveries, and emotional and non-rational aspects. This hat is a suitable tool for pouring out feelings and emotions. Black hat type thinking (limitations): By wearing this hat, negative but real aspects, limitations, problems, bottlenecks and pessimistic facts related to a phenomenon or issue are expressed. Yellow hat thinking (benefits): With this hat, positive and optimistic but realistic aspects related to a phenomenon are examined. Green hat thinking (creativity): Green hat is used to express new and creative opinions, ideas and solutions. Blue hat type of thinking (management): The blue hat performs the task of managing, controlling and organizing the other five types of thinking. By wearing this hat, a person evaluates and organizes the thoughts of other people. . It seems that the effect of six hats on the critical thinking of students who are different in terms of academic performance (strong, average and weak) has not been investigated so far. Therefore, the main goal of this research is to investigate the effectiveness of the six thinking hats technique on the critical thinking skills of the fourth grade students in the three dimensions of creativity, cognitive maturity, and mental involvement, according to the students' academic performance.
Materials & Methods
The current research is an applied research in terms of its purpose; Also, in terms of method, it is a quantitative research of semi-experimental type with a pre-test and post-test design with an experimental group and a control group. The statistical population of this research includes all fourth grade female students in district 15 of Tehran in the academic year 2022-2023, which includes 25 primary schools, 53 classes and 1550 students. The sampling method in this research is a random cluster. Azadi Primary School, which had 2 fourth grade classes, was selected among the 25 girls' primary schools of the second period of the 15th education district of Tehran. Due to the selection of the real classroom unit as the control and experimental groups, the number of students in the experimental and control groups was 30 and 31, respectively. In order to collect data, Ricketts (2003) critical thinking questionnaire was used. This tool has 33 questions and includes 3 subscales. The intervention was that six thinking hats were taught in the experimental group in 12 one-hour sessions for 3 months. This research was carried out in the second round of the academic year 2022-2023, and in the data analysis, the report cards of the first round were used to divide the students into three categories: weak, medium and strong. It should be noted that in the implementation of the six thinking hats technique, students were not categorized and their division was done only in data analysis.
Discussion & Result
According to the findings, the Six Thinking Hats technique is effective in improving students' critical thinking skills in the three components of creativity, psychology, and mental engagement. There is no significant difference between strong and average students as well as average and weak students (p < 0.05) on the effect of the six thinking hats technique on students' critical thinking skills based on their academic performance. But this difference is significant between strong and weak students (p<0.05).
Conclusion
The six thinking hats technique improves students' critical thinking. By creating an organized structure for discussion, this technique helps students to examine the topic from different angles and express their ideas clearly and reach conclusions.This teaching method is most useful for strong students who have basic critical thinking skills. Strong students can use the Six Thinking Hats technique to explore concepts more deeply and provide more detailed analysis. Weaker students can benefit from it in developing basic critical thinking skills.