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Online Symposium: Piaget, Constructivism, and Beyond
Does Piaget Still Have Anything to Say to Chemists? Diane M. Bunce Department of Chemistry, The Catholic University of America, Washington, DC 20064
Journal of Chemical Education, Vol. 78, p 1107, August 2001. Copyright ©2001 by the Division of Chemical Education of the American Chemical Society.
Does Piaget Still Have Anything to Say to Chemists? Diane M. Bunce Department of Chemistry The Catholic University of America Washington, DC 20064 Introduction In 1975 Herron (1) wrote an article for this Journal entitled “ Piaget for Chemists” that started many teacher-chemists thinking about why students were not succeeding in their chemistry courses. For many, this article served as their first introduction to Piaget’s theory of cognitive development. The article had a large impact on how many viewed the students in their classes that were having trouble learning abstract concepts in chemistry. Even today, when new teachers read Herron’s article, many are struck by the idea that numerous chemistry topics are abstract and may be beyond the intellectual reach of the majority of their students. Teachers often see themselves faced with two alternatives to this dilemma – 1) teach the course on a lower conceptual level that the majority of students can understand, or 2) find ways to help students acquire the abstract level of thinking required to be successful in this subject. Some teachers select the first option for the education, nursing, and other nonscience majors because they feel that this is the only way the students will pass the one chemistry course they take. The teachers take the second approach with the science majors. But is either of these approaches acceptable? What do Piaget’s and other models offer the teacher who is faced with such a choice? Developmental and Learning Theories Piaget Piaget was not an educator. Rather, he was a developmental psychologist and as such was more interested in how children develop mental processes as they mature than he was in developing the best ways to teach. In fact, it was the educators, not Piaget, who searched for ways to incorporate Piaget’s theory into curricula. Piaget observed the behavior of children and then used these observations to reason to a logical framework for cognitive development. Piaget demonstrated that the child is not a blank slate in regards to knowledge, but rather, has pre-conceived notions of how things work (2). Sometimes these preconceived notions are in conflict with the scientific view of the world. Piaget also demonstrated that the child is constantly involved in the process of re-examining these notions and modifying them based on new incoming knowledge. The ability to successfully re-examine or modify this new knowledge improves as the
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child matures, and can be classified according to a hierarchical series of cognitive levels from sensori-motor to formal (3) as shown in Table 1. And, lastly, Piaget showed that the child is motivated to acquire new knowledge and is best encouraged by activities that interact with the environment. Table 1. Piaget’s Levels of Development Level
Approximate Age
Sensori-Motor
Birth to two years
Pre-operational
2 to 7 years
Concrete Operational
7 to 11 years
Formal Operational
11 to adulthood
Some of the tenets of Piaget’s theory were challenged by Vygotsky (4), a contemporary psychologist. Vygotsky objected to Piaget’s lack of emphasis on the interaction of learners with peers or adults. According to Vygotsky, higher cognitive functions develop as a result of the interactions between individuals, and then are incorporated into the individual’s framework. Piaget did not acknowledge the need for such interaction as long as the individual child was provided with opportunities to interact directly with the physical environment. The educational implications of the combined theories of Piaget and Vygotski (4) include the following: 1) the student should be at the center of the learning process; 2) students learn by interaction with both their physical environment and other people (peers and adults); 3) teaching should emphasize the process, not just a correct answer; and 4) teaching should accept individual differences in students and provide for them. Constructivism Upon examining Piaget’s theory, many similarities to the Constructivist and Information Processing learning theories appear. Bodner (5) defines learning in the Constructivist Theory as the process by which “knowledge is constructed in the mind of the learner”. This view of learning, like Piagetian Theory, places the student at the center of the learning or developmental process. Bodner sees Constructivism as a logical extension of Piaget’s theory. Indeed, the two theories do agree on many aspects
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such as the centrality of the student to the learning process, assimilation of incoming knowledge with the student’s pre-existing notions and the resulting accommodation of new knowledge within the student’s understanding. When taken to its natural conclusion, Constructivism can lead to the question of whether there is any objective truth outside the mind of the learner. If a learner constructs knowledge and this knowledge is shaped by the individual’s experiences and beliefs, can two individuals ever agree on any objective knowledge? Bodner argues that constructed knowledge must be continually tested against the reality of objective knowledge outside the mind of the learner. Comparison to knowledge “out there” is part of the process of fitting knowledge into our own pre-existing mental frameworks and thus, objective knowledge does exist outside the mind of the learner. Anderson et al, (6) also describe the development of Constructivism as an outgrowth of Piagetian theory. Both theories hold that learners (students) must be engaged in the process of learning. The teacher’s task is to develop experiences to help students engage in this process. Anderson et al. contend that Constructivism breaks down if teachers do not realize that when students do not learn on their own, some direct instruction must be provided. This supports Vygotski’s belief that children must interact with adults or skilled peers in order for cognitive development to advance. Information Processing Information Processing (4,6) divides knowledge into rules or schemas by which we organize knowledge. The bases of Information Processing theory are the interactions among schemas in a student’s mind. Information Processing offers educators and psychologists an explicit model of how new knowledge is used by the learner to modify existing notions. It is a model that can be tested by a direct empirical approach and thus lends itself to validation by research. Advantages and Limitations of Piagetian Theory In many ways, Piaget’s theory revolutionized the way society thought about the cognitive development of children. Piaget is credited with influencing educators to focus on the process by which children construct an answer, not the answer alone. Educators, who were influenced by Piaget’s theory, deemphasized the traditional lecture and placed more emphasis on providing a variety of activities that enable students to interact with the physical world. Curricula were examined to determine whether children were being taught concepts that they were not yet able to learn. Educators also came to realize that while
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children’s sequence of development through the levels that Piaget suggested might be the same, their rate of progression differed. Therefore, success should include the rate of progression, not only student achievement as compared to normative standards. Piaget’s theory has some limitations. He underestimated the abilities of young children and overestimated those of older children and young adults (4). Research studies show that Piaget overestimated the fraction of students in chemistry classes who are able to handle abstract concepts successfully. For instance, Dale (7) reported that 25% of the 15-year-olds in his study were formal thinkers, while Herron (1,8) showed that 50% of his college non-science majors were formal. Lawson (9) and others (4) argue that students at different Piagetian levels share common characteristics as they mature. Few abilities are completely absent at one cognitive level and suddenly appear in the next. Rather, abilities develop across Piagtian levels but are more consistently evident in one level than the next. Thus, some aspects of Piaget’s theory of hierarchical cognitive level development may be too limiting to account for the complexity and variety of human cognition. Psychologists who have expanded on Piaget’s theory (2) believe that the determination of a child’s development should place more emphasis on the roles of strategies and skills that the child possesses, and de-emphasize the classification of a student at a certain level of development. In addition, there should be more emphasis on the child’s ability to handle a specific task and the importance of dividing cognitive problems into smaller, more precise steps. It is also the belief of these psychologists that children exhibiting a majority of the cognitive abilities of one of Piaget’s levels can be taught to reason at a higher cognitive level through the use of appropriate selected activities and interaction with skilled adults or peers. Having discussed an overview of these developmental and learning theories, we now turn our attention to teaching methods and materials based upon these theories that address ways to promote learning in chemistry. Teaching methods based on developmental and learning theories Student at the center of the learning process Putting the student at the center of the learning process means providing the student with ways to incorporate new knowledge into the framework of knowledge the student already has. These activities should review the knowledge the student already possesses and capitalize on it. For instance, several
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research studies (10) have documented the misconceptions students hold concerning the processes of melting and dissolving. In the everyday use of the words, melting and dissolving are often used interchangeably while in the study of chemistry, they represent two distinct concepts. Rather than just teaching the definitions of these concepts, a student should be encouraged to compare his or her understanding of the two before a more detailed description is presented. For example, presenting chemical demonstrations of the two processes such as the melting and dissolving of sugar cubes in two different test tubes, and asking students to write an explanation of they observe can accomplish this. Through discussion of their answers, the students’ understanding of melting and dissolving can be clarified and compared with that of a chemist. Some curricula focus the learning process on the student by asking them to discuss or recall the knowledge they already have on science-based topics in the news. Chemistry in Context (11) does this for the topics of global warming and ozone depletion as a lead-in to a detailed study of these phenomena from a chemical point of view. These discussions are time well spent helping students become aware of their current understanding of the topics before new knowledge is presented that ultimately can be incorporated into their cognitive frameworks. Learning through social interaction In small co-operative learning groups, students work with peers and adults to help incorporate new knowledge. In these groups, students discuss how to solve chemistry problems. Some teachers use this approach in laboratory settings. Others use it in lecture and/or recitation sessions (12-13). The important aspects of these co-operative activities are that they are designed to challenge students’ current knowledge and require students to seek new knowledge, compare and contrast previously learned knowledge that has been compartmentalized, or apply knowledge that has just been presented. The members of the group learn from each other (peers), teaching assistants or professors (skilled adults) in terms of the students’ understanding, not the teacher’s. The questions asked by members of the group reflect where the students are in the learning process, rather than where the teacher imagines they are. For example, students often keep their understanding of the concepts of concentrated/dilute solutions separate from that of strong/weak acids even though both can be used simultaneously to describe a solution. A co-operative activity can be used to help students compare and contrast these two concepts. In this specific activity, each group is asked
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to represent one of the following: a concentrated, strong acid; a dilute, strong acid; a concentrated, weak acid; or a dilute, weak acid. Discussion among the members of the group helps students confront their own understanding or lack of it. Eventually most groups come to understand how to represent a concentrated strong acid (a lot of acid molecules compared to the number of water molecules (concentrated) dissociated entirely into their ions (strong acid) vs. a dilute, weak acid (a few acid molecules compared to the number of water molecules (dilute) with only a few dissociated into ions (weak acid)). Presentation of each group’s representation helps all students learn how to express both these concepts simultaneously. The inevitable repetition provides students with practice of the concepts, a chance to critique the presentations, and time to assimilate the new knowledge. When division of the class into small groups is not practical, students can still learn to integrate new knowledge with that previously held through whole-class activities such as ConcepTests. A ConcepTest (14) is a question/problem posed by the teacher in lecture, an initial vote by the students through a show of hands on one of several possible answers followed by a two-minute discussion during which students discuss and defend their positions. After the discussion, a second vote is taken to determine the students’ current understanding of the concept. ConcepTests provide many of the benefits of cooperative learning groups by affording students an opportunity to integrate knowledge by asking questions of and providing explanations to their peers. Use of ConcepTests also refocuses class time on student understanding rather than teacher lecturing. Emphasis on process Categorizing problems and dividing them into sub-problems is the goal of a generalized but explicit problem solving approach (15). Here students categorize problems by analyzing and planning a problem solution before the problem’s numbers are manipulated. By reviewing the plan after the problem is completed, students see trends in problem solutions. For instance, stoichiometry problems are often confusing to students (10,15). Students view each one as unique rather than categorizing them as massmass, mass-mole, or mole-mole problems. If students break the solution down into steps such as: 1) the conversion of grams of one substance to moles, 2) the relationship of moles of this substance to moles of another substance and finally, 3) moles of the second substance to grams, then the solutions of subsequent problems are viewed as variations of this problem. After repeated stoichiometric problem solving, the
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importance of the central relationship of two different substances to each other on the basis of moles via a balanced equation becomes apparent to the student. Providing for individual differences Students learn by using visual, auditory and kinesthetic approaches. Traditionally, chemistry has been taught through lectures (auditory) with the visual often supplied by the symbols and equations familiar to most chemists. Kinesthetic approaches have included “hands-on” approaches where students experience the science they are learning. If we concentrate on the visual approach used, most symbols and equations that are rich in information for the chemist, may not convey the same wealth of information to the student. Chemists interpret the symbols of a chemical reaction as representing molecules, atoms, or ions. They understand the interaction among these particles implied by the equation, but students may not. The need by students for visual representations of the interaction of particles involved in a chemical reaction has been documented in the literature (16-19). These studies show that sometimes even when students do well on traditional chemistry problems involving such things as chemical reactions, balancing equations or gas laws, they may not understand the underlying concepts (15), thus the need for a visual explanation of the behavior of particles responsible for these chemical phenomena. The most common way to teach understanding of how particles interact is by using particle diagrams where circles or other geometric shapes are used to represent atoms, ions or molecules. These diagrams have become more common in textbooks (20-21) and on the ACS General Chemistry Exams (22-23). Some research suggests that animations of such diagrams may be more effective in conveying the interactions between particles than static paper and pencil diagrams (24). Are particle diagrams equally helpful to all students? Will they interfere with the learning of students who don’t need them? In an attempt to answer these questions, a study was done by Bunce and Gabel, in conjunction with ten high school teachers, to investigate the effect of using particle diagrams on the chemistry achievement of 448 high school students from ten schools. Three two-week modules on Matter, Solutions, and Stoichiometry were taught to 10 treatment and 10 control classes. The treatment classes used demonstrations, particulate diagrams, and typical chemical symbols/ mathematical equations. The control classes used only two of these approaches (demonstrations and chemical symbols/math
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equations). Analysis of treatment-gender interactions showed significant gains in achievement for treatment women (p = 0.03), while not significantly affecting that of men (Table 2). Table 2. Overall Achievement Scores of Treatment vs. Control by Gender n
Mean
116
30.6
76
30.7
Treatment Groups Treatment Men Treatment Women Control Groups Control Men Control Women
133
31.2**
70
28.0
Treatment Women
76
30.7**
Control Women
70
28.0
Treatment Men
116
30.6
Control Men
133
31.2
Women
Men
** Significant at p < 0.005 According to Herron (1), a larger proportion of men exhibit formal reasoning than women and thus men are more likely to be successful in the study of abstract chemistry concepts. Table 2 shows that control men did score significantly higher than control women when no particle diagrams were taught. There was no significant difference in the achievement scores of men who were taught using particle diagrams (treatment) compared to those who were not (control). However, treatment women who were taught using particle diagrams, did score significantly higher than control women and this increase raised the scores of treatment women to a level of achievement equivalent to that of men (treatment and control). Other research (25) suggests that men are better able to develop their own visual models than women, but, once women learn to use visual models, they use them more effectively. Using particle diagrams in teaching
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abstract chemical concepts provides women with the visual models they need and thus helps more of them achieve at the same level as men Testing In order for these new teaching methods to be effective, testing in chemistry courses must reflect the emphasis on how well students understand chemistry. In other words, students’ explanations of why something happens must be evaluated in addition to the factual or numerical answer. Just because students do well on a particular test, does not necessarily mean that they understand the underlying chemical concept. Students may be passing tests by applying algorithms that match the beginning conditions of the problems and result in the determination of correct answers. Herron (1) warns that even when students appear successful (based upon course test grades), they may not actually be learning. Instead, these students may be “parroting words without appending meaning to those words”. This is a serious problem that is not always addressed through the use of multiple choice, short answer, or algorithmic problems. Including different types of test questions such as essay questions that ask students to explain the underlying concept used to solve a problem encourages students to seek understanding of concepts. Implications The chemistry teaching profession is in the midst of change both in what and how it teaches. Much of this change is guided by the premise that students should be at the center of the learning process. With students at the center, it becomes more important to ascertain what students have understood rather than what content should be covered in lecture. The suggestion is not that the teaching of chemistry should be made easier by leaving out abstract chemical concepts. Rather, the goal is to provide a better match between what students are capable of understanding and how we teach these concepts. Consideration of the developmental and learning theories presented here, leads a teacher of chemistry to several conclusions. The most important is that teaching and lecturing are not necessarily the same thing. Lecturing, as often practiced, may not be student-centered nor student engaging to bring about learning. Student-centered teaching is dependent on the interaction between student and student or student and teacher. It is, by definition, student engaging or student-active. The teacher’s role in such teaching situations changes but is not diminished. The teacher becomes responsible for finding and/or creating learning experiences, accessing students’ prior knowledge through students’ explanations of chemical phenomena, and using
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compare-and-contrast techniques, particle level explanations, co-operative learning, ConcepTests, and other methods that will help students integrate new knowledge into their cognitive frameworks. So how do we encourage teachers to integrate a student-centered focus into their teaching? Just as with the students, we must engage teachers in the process of learning. This engagement may take the form of a discussion of how effective, teachers perceive their lecturing to be. Sometimes this is accomplished by focusing on student evaluations of the course or by examining the number of students who vote with their feet (withdraw) or fail chemistry courses. What explanations do chemistry teachers give for this student behavior? Is the response that the students are lazy or stupid or under-prepared? All of these may be true in some instances, but why do so many teachers experience these same student reactions? Only when these questions have been raised, can we start a meaningful discussion of why students are not choosing to learn chemistry. If this information is teamed with the results of asking our students to explain chemical concepts in their own words shortly after they have been taught these concepts, we can expand the discussion to “why don’t students learn chemistry?”. Now the stage is set to help teachers rethink the way they present chemical concepts. Questions need to be raised as to whether we are teaching to satisfy our own logical understanding of chemistry or to help students formulate their understanding. If we want students to develop their understanding, then we must teach chemistry in a way that is aligned with how Piaget and the other developmental psychologists and learning theorists have showed us students learn. As presented in this paper, there are various approaches other than a conventional lecture that will encourage the engagement of students in the learning process. Engagement of students in their only learning is the necessary first step. Piagetian theory has helped us focus our teaching on the student. We are challenged to accept the responsibility for bridging the gap between where our students are in their learning and where we expect them to be. Piaget started a revolution in how we approach teaching and learning. His theory prompted many teachers and researchers to think about the mismatch between the way we teach and the way students learn. As a result of this activity, Piaget’s theory has been expanded and modified, and in some cases even rejected in favor of more emphasis on the process of learning. It is no longer enough to recognize that not all students in our chemistry classes can understand the abstract concepts of chemistry by listening to our lectures. As teachers we must accept the responsibility to affect the quality of learning for all students on each concept by paying attention to how the concepts are experienced by the students. Piaget introduced us
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to this view and took us a considerable distance in thinking about how to accomplish it. Now it’s time to move further in our understanding and action than Piaget can take us. It is time to turn to the newer theories that have expanded on the original insights that Piaget presented.
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21. Kotz, J.C.; Treichel, P. Chemistry & Chemical Reactivity, 3rd ed.; Saunders College Publishing, Harcourt Brace & Company: Orlando, FL, 1996.
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