2.9 Constructivist and Cognitive Science Theories

Science educators, particularly over the past twenty years, using the work of Jean Piaget as a foundation, have developed a number of theories to explain cognitive learning. In general these researchers are interested in how information is taken into the organism, interpreted, represented and acted upon. These science educators agree with Piaget, that knowledge is constructed, and theorize that students are builders of knowledge structures. These science educators, also referred to as cognitive scientists have developed a number of alternative models that have direct implication for teaching science to secondary students. The models that are discussed below represent recent work being done by cognitive scientists. Although these models differ in some respects, they share the following characteristics (Resnick and Kloper, 1989):

1. Importance of content knowledge

Cognitive scientists put a lot of emphasis on what they call "expert knowledge." They suggest that "experts," say in physics or geology reason more powerfully about a topic in their respective fields than a novice. In fact one of the things you will find common in the models that follow is an attempt by teachers to find out what the novice learner (your students) know about a topic before teaching them new concepts. Another idea that cognitive scientists have put forth is that learning requires knowledge, yet knowledge cannot be given directly. Students must generate their own knowledge. Yet for this to be done, the teacher must provide a learning environment where students can discuss and question what they are told, investigate new information, and build new knowledge structures. Further, teachers need to provide ways to ascertain what students know, and then find ways to link this knowledge (which quite often is naive) to new knowledge structures.

2. Integration of skills and content

Because the cognitive approach places the student in the center of learning, the development of thinking skills must be integrated with content knowledge. This is, of course, an idea proposed by many other theorists, especially Piaget and Bruner. It is just as important for students to observe, question, test, hypothesize, as it is to develop cognitive structures about gravity, electrons, plate tectonics, and carnivores. In fact, without observing, questioning, testing, and hypothesizing, the student has little chance of developing scientific conceptions about these or any other concepts.

3. Intrinsic nature of motivation

This is a major change in the emphasis for cognitive scientists. Typically, motivation has been the subject of social psychologists who are interested in attitudes, effort and attention. Cognitive scientists have realized the importance of developing a learning environment in which students will want to learn. Cognitive scientists, unlike the behaviorists, focus their attention on the intrinsic nature of content and instruction as a means to motivate Cognitive scientists are also learning that students' concept of self can be a contributing factor in motivation. Resnick and Klopfer report that social psychologists have found that motivation is closely related to students' conceptions of intelligence. In one study, if students helped to understand that intelligence is an incremental ability, rather than a fixed entity, the students who believe the former, when faced with challenging or difficult problems, stick with the problem, and try to use what they have to solve the problem. The latter students, according to the researchers, might in some cases give up saying that they lack the intelligence to find the solution. Interesting, thought provoking, challenging and stimulating approaches to instruction may motivate students more so than the positive reinforcers suggested by behavioral psychologists.

4. Role of learning groups

Cognitive scientists believe that the social setting for learning is crucial. They have found that cooperative problem solving groups have been effective with students of varying abilities. Resnick and Klopfer suggest that skilled thinkers (the instructor or high ability students) can demonstrate desirable ways of solving problems, thereby helping students who lack these mental abilities or experiences. The implication for the science teacher is to develop in the classroom open, positive communication patterns, and to place students in small, mixed ability cooperative groups where social interaction can occur. In either case, cognitive scientists are calling for the formulation of "social learning communities," environments where questioning, critical thinking, and problems solving are valued. According to cognitive scientists, these learning communities can be critical in helping the less able student learn thinking patterns that the more able student possess.

Constructivist Model

According to the constructivist theory, a large number of students show up in science classes with lots of ideas about science concepts, many of which are "incorrect," naive or are as these researchers call them, as misconceptions. The aim of science teaching is to "help students overcome naive conceptions or habits of thought and replace them with scientific concepts and principles."

First let's consider the nature of some misconceptions in science, and then describe a theory to improve students' understanding of science.

In a physics or physical science class, the coin toss problem will illustrate the problem of misconceptions. The problem, shown in below is an application of Newton's laws of motion. A coin is tossed upward in the air, and the student is asked, "What are the forces on the coin at point B, when it is moving upward through the air? The typical answer to this problem by students is, "while the coin is on the way up, the 'force from your hand' (Fh) pushes up on the coin. On the way up it must be greater than the force of gravity (Fg), otherwise the coin would be moving down." The expert or physicist answer is the only force acting on the coin at point B is the downward force due to gravity (and a small additional downward force due to air resistance). Anderson and Smith report that in one study of college engineering majors, who had a course in high school physics, the percentage of students answering the question correctly after instruction rose from 12% to only 28%.

In chemistry, an example of a misconception is illustrated when a student, four months into the course, is asked to explain what happens when a nail rusts. His explanation is

...the coldness reacts on it [the nail]...plastic doesn't rust because coldness doesn't cause the same reaction...rusting is a breakdown of the iron because it [coldness] brings out the rusting...it [coldness] almost draws it [rust] out, like a magnet...like an attractor it brings it out (Anderson and Smith, 1987, p. 88).

Anderson and Smith (1987) report that this student consistently said he was satisfied with his explanation, that they made sense to him, and that scientists would explain the situation the same way. Misconceptions make sense to the student, and they are firmly held to the learner as a mental structure. This makes things very difficulty for the science teacher!

Students hold misconceptions in all areas of science. In a biology class, students were presented with "the amputated finger problem:" If a little girl had an accident and her finger was amputated and she married someone with a similar amputation, what would you predict their children's fingers would look like at birth? Even after instruction in a unit on genetics, students had the following misconceptions: "The finger was cut off too fast for the genes to change;" "The child will probably have a finger missing because the traits of both parents are strong;" and "The lost finger would be inherited from the parents."

Let's look at some misconceptions that student's bring to Earth science classes. Following is a list of Earth science misconceptions in several conceptual areas:

Even after instruction, misconceptions are still prevalent among students in science classes. Teachers who direct their attention at student misconceptions report that a student misconception is "knowledge spontaneously derived from extensive personal experience."Because these misconceptions were derived by students, and they make sense to them, the students often hold on to these ideas in spite of alternative (scientific) conceptions. Since it is assumed that knowledge cannot be given directly to the learner, the task of the teacher who focuses on misconception theory is as follows (Anderson and Smith, 1987):

1. Help the student become dissatisfied with their existing conception.

2. Help the student achieve a minimal initial understanding of the scientific conception.

3. Make the scientific conception plausible to the student.

4. Show the scientific conception as fruitful or useful in understanding a variety of situations.

Lawson and Thompson (1990) point out that the intellectual level of the students will effect student understanding in science, and may prevent some students from understanding the scientific conception, especially if it is expressed as a theoretical conception. They suggest that the concrete student lacks reasoning patterns necessary to evaluate competing hypotheses (e.g., the hypothesis of the inheritance of acquired characteristics [the typical misconception] versus the natural selection of genetically acquired characteristics). They may be unable to reject the naive inheritance theory because they do not understand the concept of natural selection and gene transfer. The implications of this study is teachers should provide students with opportunities to discuss their prior conceptions and carefully compare them with the scientific conceptions. Another, and perhaps more important implication, is that we need to develop alternative ways of expressing concepts, as suggested by Bruner.

Constructivist research has led to a theory of instruction in which the students' prior conceptions are detected, time is provided for the students to compare their misconceptions to the scientific conceptions, and finally an opportunity to use the new conceptions in a variety of learning situations. The classroom implication of conceptual-change teaching will be discussed in Chapter 7.