Analysis of students’ critical thinking skills with reflective and impulsive cognitive styles on conservation and environmental knowledge learning

The research types used in this study included (1) pre-experimental research using a One-Shot Case Study design, referred to in Sugiono (2008). One-Shot Case Study is a single treatment design; an experiment is carried out without a comparison group and also without initial tests. To develop students' critical thinking skills, we carried out a learning process on conservation and environmental knowledge by a using group investigation model based on a contextual approach. They also included (2) descriptive exploratory research, to describe students’ critical thinking skills with reflective versus impulsive cognitive styles; (3) comparative research, to see the difference between the critical thinking skills of students with reflective versus impulsive cognitive styles. The research subjects were 26 students of the biology education class in 2013: 13 students had a reflective cognitive style, and 13 students had an impulsive cognitive style.

This research is conducted in two stages: the first stage of the research to measure cognitive style and the second phase of research to measure critical thinking skills.

The instrument used to measure cognitive style is MFFT, developed by Warli (2010). The MFFT instrument includes one standard image and eight variation images. Through this instrument, the student is instructed to select one of eight variation images and the same with the standard image. The observed variables are the time required by students to answer the question for the first time and the frequency of answers until the correct answer is produced. According to Warli (2010), the four groups of students found using this test include: (1) the group of students who have characteristics to answer quickly the problem carefully/thoroughly so the answer is always right; (2) the group of students who have characteristics to answer quickly the problem carefully/meticulously so that answers are always right (reflective student); (3) the group of students who have characteristics to answer quickly but with less accuracy/less precision so that the answers are often wrong (impulsive student); (4) the group of students who have the characteristics of slowly answering the problem with less accuracy/less precision so that the answers are often wrong.

Specifically, the MFFT process used here involved: (1) calling the students one by one to complete the cognitive style test through the instrument MFFT by seeking a variation of images corresponding to the standard image; (2) recording the time used by the student to answer the question for the first time; (3) recording the frequency of answering until the participants obtain the correct answer; (4) calculating the amount of time and frequency of errors then dividing them by the number of items to obtain the average; (5) looking for the median of time (t) and the frequency (f) and then drawing the chart line, which is parallel to the axis t and axis f, to make the four groups of students.

The instrument used to measure critical thinking skills was an essay test measuring the ability of critical thinking with a total of six questions:

Please identify the number of possibilities that will occur in the environment if limestone mining in some Tuban sub-districts is not limited.
What is on your mind if a reclamation is carried out along the northern coast of Tuban?
What are the causes of the accumulation of waste in the Tuban district, and what are the consequences of this garbage pile?
Is it wise for us to use plastic equipment without regard to symbols/codes as a place for daily food and drinks?
Do you agree if the number of four-wheeled vehicles or two-wheeled vehicles continues to increase for the sake of people's welfare?
What should we do if this environment is maintained?

Those questions are used to measure the critical thinking that refers to the sub-indicators (Ennis, 1996), which include: (1) identify or define criteria for consideration of possible answers; (2) provide an explanation; (3) identify the inaccuracy; (4) show the ability to give a reason; and (5) select the criteria to consider possible solutions. Also, to determine the score of critical thinking skills refers to the standardization, we use Paul and Elder’s (2007) assessment criteria, which include: clarity, accuracy, precision, depth, breadth, and logic, which are adjusted to learning conservation and environmental knowledge.

To empower critical thinking skills, the students used the group investigation model based on the contextual approach. Characteristics of conservation learning and environmental knowledge using a group investigation model based on contextual approaches included the following steps. 1) Learning is directed so that the students have the skills to solve real problems. The grouped students are assigned to the field to observe environmental problems according to their topic. 2) Learning provides opportunities for students to do meaningful tasks. In this case, the students are assigned to identify the causes of environmental problems by the topics that they choose and may provide alternative solutions. 3) Learning is carried out by providing meaningful experiences to students. By being assigned to the field to observe environmental problems directly, it is expected that students will have a meaningful experience. 4) Learning is carried out through group work, discussion, and correcting each other at the presentation.

The overall assignment was organized using the six stages of the learning group investigation model, according to Slavin (2008). The first phase entails to identify the topics and form the groups with three to four students. The topics were environmental issues commonly familiar to the students. The second phase entails the students planning investigations conducted in groups based on their chosen topic. Phase three entails the students carrying out an investigation based on their chosen topic. The students are in groups, conducting investigations into the field to collect, analyze, evaluate, make conclusions, and apply new knowledge for solving the above problems examined by the groups. In this stage, each group takes approximately two weeks. Stage four entails the students to prepare the final report. In this stage, all students collect the results of the investigations at the same time. Stage five, the students make a presentation of the final report. Stage six of the evaluation is conducted at the end of the semester during the Semester Final Exam. This phase was used to obtain data on students’ critical thinking skills.

Furthermore, the data on critical thinking skills of students with reflective and impulsive cognitive styles are analyzed through SPSS program version 19 by using the non-parametric Mann-Whitney test.