Exploring how students learn organic chemistry. (The scholarship of teaching and learning).

Abstract

The overwhelming volume of information in contemporary chemistry classes makes the role of instructor as purveyor of content an unrealistic task. We have therefore become more concerned with helping students understand information and process new concepts. We studied the effect of collaborative and problem-based learning (PBL) on students' approach to their learning and on the quality of their learning outcome. Our results reinforce and extend prior data, namely, that collaborative learning helps students take a deep approach to their learning, and PBL helps students see connections to science in society. We found that carefully designed PBL problems can promote content acquisition. We discuss strategies for dealing with the challenges we discovered in using these pedagogies such as how to help students successfully transfer information from the PBL contexts and promote students' intellectual development.

Introduction

How we teach reflects our underlying goals for the kinds of learning we expect from our students. We may not always deliberately examine and articulate these goals, however, either to our students or ourselves, especially when we teach in very content-demanding disciplines. But if we wish to be the best possible teachers that we can be, then we need to ask ourselves, what is learning to us, and how is the best way to facilitate that learning?

Learning may be described on one hand as increasing students' information content including their memorizing facts or methods for later use. On the other hand, learning may be viewed as enhancing students' ability to abstract meaning and interpret perceived reality. A teacher's goals for learning will dictate her preferred teaching styles. Educators who view teaching as a transfer of information adopt a more teacher-centered classroom style, and the learning outcomes appear to be more fact-based. Whereas teachers who view learning as transforming students' thinking adopt a more student-centered classroom style, and the learning outcomes in those classrooms appear to be less fact-based and more related to conceptual change (Prosser & Trigwell, p. 156).

In reflecting on our practice and the goals for our students' learning outcomes in organic chemistry, we realized that "covering" all important content with our students was becoming an impossible task given the already vast and rapidly increasing wealth of information known in organic chemistry. We became more interested in helping students understand and decipher the information that was available to them and enhance their ability to deal with new ideas as they encountered them. We became concerned that the traditional method of teaching in the discipline, that is, lecturing, even when punctuated with interactive question/answer sessions, did not promote this learning for understanding, sometimes called "deep learning," in our students. The lecture is a useful vehicle for transmission of information, but it may not engage students in processing and integration of ideas and concepts. We decided to examine the effect of collaborative and problem-based learning (PBL) on our students' approach to their learning and the quality of their learning outcome. We wanted to know if collaborative methods helped motivate our students to deeper learning and if PBL enhanced or detracted from this process.

Our study may help answer questions that faculty have about collaborative or problem-based learning such as: Will it improve content acquisition? Will students be more engaged? Will students like this approach? Our assessment tools are of broad utility and include the Approaches to Study Questionnaire (ASQ) (Richardson, 1990) that we used to analyze students' approach to their learning and the Structure of Observed Learning Outcomes (SOLO) taxonomy (Biggs & Collis, 1982), a hierarchical rubric that describes students' responses to essay questions in terms of their ability to link concepts properly. Our results reinforce the data showing the potential power of these pedagogical techniques as well as pointing out the challenges associated with them. In particular, we found that collaborative learning helps students take a deep approach to their learning, and PBL helps students see connections to science in society. We found that in some cases the use of real life issues in PBL can promote course content acquisition, but this outcome is neither automatic nor trivial to achieve. We discuss students' response to these pedagogies, both negative and positive, in the framework of Perry's model of intellectual development.

Theoretical Context

Pedagogies extending beyond the lecture method are of interest for those concerned with how students best learn science (McNeal & D'Avanzo, 1997; Science teaching reconsidered, 1997). Specifically, cooperative learning has been shown to enhance student achievement in introductory chemistry (Bowen, 2000) and introductory physics (Hake, 1998). Collaborative learning is sometimes treated as synonymous with cooperative learning, but collaborative learning may refer more to work in groups on questions that have no "right" answer and may include complex, controversial societal issues (Bruffee, 1999; Matthews, 1995). Using cooperative/collaborative learning methods coupled with studying content in the context of a socially relevant problem may be defined as problem-based learning (PBL). PBL has been used extensively in medical schools and is valued because it engages students in constructing knowledge, developing expertise in analyzing problems and functioning as part of a group (Margetson, 1994; Wilkerson & Gijelaers, 1996). This method can help students move beyond a superficial examination of questions and enable students to reach higher levels of reasoning sooner.

Pedagogies involving students in collaborative activities may help students in their moral and intellectual development as described by Perry (1970), reinterpreted specifically for women learners by Belenky, Clinchy, Goldberger & Tarule (1986) and adapted and examined in science classes by Nelson (1989; 1999). Students typically enter introductory level science classes with a dualistic right/wrong approach, called received knowledge by Belenky, et al., that contributes to reliance on the professor's authority and on fact-based learning. The highest levels of development in Perry's model are the contextually relative and commitment in relativism modes. These modes represent students' abilities to adapt the best theories for a specific context and to accept explanations based on the best theories and their own beliefs. Similarly, Belenky, et al., described the most integrated way of viewing knowledge as that of constructed knowledge in which knowledge and truth are contextual. These theories provide another framework for viewing deep learning, or learning for understanding. Moving students into a more integrated, contextual approach to knowledge is very difficult and requires both challenge and support. The group structure inherent in collaborative learning could help provide both.

Class Format and Assessment

The context of our study is a small liberal arts college for women. Each author taught a section of organic chemistry in the fall semester using collaborative learning. This class is the first in a yearlong sequence designed for science majors and students preparing for health professions and is typically taken by students in their sophomore year. Students were assigned to groups of 4-5 at the beginning of the semester based on their responses on a short learning styles inventory (Nurenberg, 1995, pp. 9-10). Groups were mixed both in terms of learning styles and prior performance in chemistry. In each section students completed Worksheets every week in which they answered questions and worked problems related to the reading assignment prior to discussion of each topic in the class. These worksheets were discussed in their groups and then with the class as a whole. Lectures were kept to a minimum, usually no more than 15 minutes, and were used to clarify difficult concepts, misconceptions and confusions.

In one of the class sections students explored certain content issues using the PBL format. In particular, students studied structure/function relationships in alkenes while researching information on the effect of trans-fat in processed foods. As a second issue students studied certain organic reactions and polymer chemistry within the context of the proverbial question at the grocery checkout line, "do you prefer paper or plastic?"

We gathered information about our students' approach to their learning with the goal of correlating approach with the quality of learning outcomes. The ASQ (Richardson, 1990) is a standard instrument designed to evoke students' responses that show whether they are taking a reproducing orientation or a meaning (understanding) orientation to their study. The questionnaire contains 32 items, 16 of which are designed so that students' agreeing with the item shows that they are taking a surface or reproducing orientation to their study. On the other 16 items, students' agreement indicates that they are taking a meaning or understanding approach.

We evaluated the quality of learning outcomes by asking open-ended questions on exams that were designed to probe students' understanding of key concepts. These items were evaluated using the SOLO taxonomy (Biggs & Collis, 1982). This taxonomy describes student learning in stages of increasing structural complexity: prestructural, unistructural, multistructural, relational and extended abstract. We shared with our students our goal for them to understand concepts at least at a relational level and gave them the following description of the taxonomy:

   Prestructural: I don't know anything about this topic.

   Unistructural: I know some isolated facts but they don't exactly apply to
   this concept.

   Multistructural: I know some isolated facts on this concept but I don't
   know how they relate to each other.

   Relational: I know several things about this topic and what they mean
   related to the broader issues.

   Extended Abstract: I can see how these facts and concepts relate to larger,
   more abstract ideas in organic chemistry.

We ascribed these levels to students' conceptual knowledge based on our evaluation of students' responses. Since the evaluation process is subjective, we each evaluated student work using these criteria to validate our individual judgements. In adapting this rubric to a science class, correct answers were ones at the relational or extended abstract level. We assigned students' answers to the other levels based on whether they used correct concepts in wrong ways (multistructural) or whether they tried to apply incorrect concepts (unistructural) in answering the question.

Outcomes

On the ASQ, students in both classes generally agreed on items designed to assess that they were taking a deep approach to study, relating ideas and using evidence. Students generally did not agree on those items designed to assess fear of failure and improvidence. Improvidence is defined as "an overcautious reliance on details" (Richardson, 1990, p. 156) and is characterized by tightly structured learning and by a failure to seek analogies or use one's own experience (Dart & Boulton-Lewis, 1998). Students not agreeing with these items may be a logical outcome of the positive interdependence of group learning.

After one semester, students who had experienced PBL answered more positively on several of those items on the ASQ reflecting that they were relating ideas or using evidence or logic when compared to the class using collaborative learning only (CL). For example:

I tried to relate ideas from organic chemistry to ideas in other
subjects whenever possible.

PBL class   100%   CL class   67%

In trying to understand new ideas in organic, I olden tried to relate
them to real life situations in which they might apply.

PBL class    65%   CL class   46%

There are not a large number of these items nor a large number of students in each class (16-20), so we should not overemphasize this finding. But it would seem a logical and hoped for conclusion that students studying real world problems related to organic chemistry content would begin to make more connections between what they learn in class with what goes on in the world outside the classroom.

Secondly, our evidence suggests that students did get a deeper understanding of some concepts that they encountered in a PBL problem compared to not having a PBL problem. We each asked students on the first organic exam to rank the boiling point of a series of three isomeric alkanes (straight chain versus branched hexanes) and explain their answer--a common question in introductory organic chemistry. We evaluated their responses using the SOLO taxonomy. All of the students in the class that included the PBL unit on trans-fat got the right order for the right reason (N = 16), relating boiling point with effects of branching on intermolecular forces. We called this an answer on the relational level. Student responses in the class that did not include PBL (N = 15) showed fewer responses at the relational level (N = 4) and more that included misconceptions or incomplete answers ranked as unistructural (N = 6) or multistructural (N = 5) depending on how far afield they were.

We continued to use the SOLO taxonomy to evaluate the quality of our students' learning of key concepts. Since our classes are quite small, there were no statistically significant differences between the two sections on the range of SOLO categories on other questions. In general, the two sections performed very similarly on items in which there was no content correlation to PBL problems. On items in which the key concepts had some relationship to the PBL, students in the class taught using PBL scored slightly but not significantly higher on our SOLO assessment of those responses.

The success of using PBL to reinforce concepts in science classes may depend on the nature of the problem studied. In the case of the trans-fat problem, the structure of the molecules was the key chemical feature directly underlying the physiological behavior of these substances. Thus, when students were asked questions on exams related to structures of similar molecules the transfer of information was somewhat straightforward. The paper versus plastic controversy by comparison involved several unrelated chemical concepts. Thus, when queried about similar concepts on examinations students were less able to pick up on learning "cues" that may be critical in transfer of knowledge. Students have a difficult time transferring abstract information from one context to another unless we specifically guide them in ways to generalize appropriately from the specific case. PBL does promote more time on task, and thus if problems are designed that both engage students' attention and focus clearly on an important foundational concept, PBL may promote deeper understanding.

Student Responses

Student responses to this approach as expressed on the semester-end student evaluation forms range from the very negative to the very positive. Typical negative responses to collaborative learning include the students' desire to have more lecturing rather than group work since they didn't feel that they could "teach each other" or themselves. These criticisms were repeated in the PBL class with the addition that this was not an "effective way to teach because she did not teach."

These negative responses may in part reflect the struggle students have in intellectual development according to Perry or in finding voice as in Belenky, et al., as we discussed earlier. Students who remain in the dualistic or received knowledge mode are going to be uncomfortable with the transfer of authority of knowledge from instructor to student in group learning activities. This observation may be particularly appropos in the case of PBL since students deal with questions for which there are no "right" answers. Science to students at this phase of development is meant to provide right answers to issues. As Nelson points out, students may be troubled by the question of "how can knowledge be both uncertain and useful?" (1999, p. 173) Therefore they may feel that they learned very little from the PBL experience.

The positive responses from students reflect a satisfaction with thinking and "work[ing] through problems rather than taking notes and memorizing" and an increase in their belief in their own ability to struggle and succeed. Students felt that this interaction would increase their ability to remember information. Some students in the PBL class thought that all science classes should be taught this way. Interestingly, one of the authors has used PBL in senior level classes for chemistry majors in which it has been met with unqualified enthusiasm on the part of students (Hodges, 1999). The different responses of students in lower and upper division classes may reflect differences in levels of intellectual development as described by Perry or students' comfort with voice as discussed by Belenky, et al. Thus, instructors wishing to use PBL to enhance conceptual understanding in lower division classes may need to provide additional structure and support for students during the process and may need to explicitly describe epistemological theories such as those of Perry and Belenky, et al., as Nelson recommends (1999).

Conclusions

What we began as a quantitative study to glean insights into the role of collaborative and problem-based learning in students learning organic chemistry became more an ethnographic study about differences in student learning and satisfaction with pedagogical strategy. The data from our small study do not definitively show that collaborative learning or problem-based learning increase students' depth of learning or markedly change their approach to learning compared to other approaches. We did discover that carefully chosen problems can promote conceptual understanding. Thus, PBL in core science classes may be most successful when used to promote learning of key foundational concepts. The data also suggest that if instructors have a particular goal for student learning, such as encouraging students to make connections between class work and societal issues, then being as explicit as possible in activities to promote this goal can result in success. And, finally, our study alerts instructors that students may not be comfortable with the shift in classroom authority inherent in these teaching strategies, especially in lower division classes.

The scholarly approach to our teaching has resulted in our being more observant of our students' learning and becoming more intentional in our teaching methods. Collaborative learning methods can make transparent the affective issues in learning. Students vary widely in their emotional comfort with this style. This aspect of the process may make the class much more challenging for professor and student alike. Hansen and Stephens (2000) point out the high ethical demand placed on us as instructors in persevering against natural student resistance to these learning-centered pedagogies. If we hope to develop students' abilities to think critically and to become lifelong learners, however, the gain may indeed be worth the pain.

Acknowledgements

We gratefully acknowledge the Pew National Fellowship Program for Carnegie Scholars and Agnes Scott College for their support of this work.

References

Belenky, M. F., Clinchy, B. M., Goldberger, N. R. & Tarule, J. R. (1986). Women's ways of knowing. New York: Basic Books.

Biggs, J. B. & Collis, K. F. (1982). Evaluating the quality of learning: the SOLO taxonomy. New York: Academic Press.

Bowen, C. (2000). A quantitative literature review of cooperative learning effects on high school and college chemistry achievement. Journal of Chemical Education, 77, 116-119.

Bruffee, K. A. (1999). Collaborative learning: higher education, interdependence, and the authority of knowledge (2nd ed.). Baltimore: The Johns Hopkins University Press.

Dart, B. & Boulton-Lewis, G. (1998). Teaching and learning in higher education. Melbourne, Australia: The Australian Council for Educational Research Ltd.

Hake, R. (1998). Interactive engagement vs. traditional methods: a six-thousand student survey of mechanics test data for introductory physics courses. American Journal of Physics, 66, 64-74.

Hansen, E. J. & Stephens, J. A. (2000). The ethics of learner-centered education: dynamics that impede the process. Change, 32, 41-47.

Hodges, L. C. (1999): Active learning in upper-level chemistry courses: a biochemistry example. Journal of Chemical Education, 76, 376-377.

Margetson, D. (1994). Current educational reform and the significance of problem-based learning. Studies in Higher Education, 19, 5-19.

Matthews, R. S., Cooper, J. L., & Davidson, N. (1995). Building bridges between cooperative and collaborative learning. Change, 27, 34-40.

McNeal, A. P. & D'Avanzo, C. (Eds.). (1997). Student-active science: models of innovation in college science teaching. Orlando, FL: Saunders.

Nelson, C. (1989). Skewered on the unicorn's horn: the illusion of a tragic trade-off between content and critical thinking in the teaching of science. In L. W. Crowe (Ed.), Enhancing critical thinking in the sciences (pp. 17-27). Washington, DC: Society of College Science Teachers.

Nelson, C. (1999). On the persistence of unicorns: the trade-off between content and critical thinking revisited. In B. A. Pescosolido & R. Aminzade (Eds.), The social worlds of higher education: handbook for teaching in a new century (pp. 168-184). Thousand Oaks, CA: Pine Forge Press.

Nurrenbern, S. C. (1995). Experiences in cooperative learning: a collection for chemistry teachers. Madison, WI: Institute for Chemical Education.

Prosser, M. & Trigwell, K. (1999). Understanding learning and teaching. London: SRHE and the Open University Press.

Richardson, J. T. E. (1990). Reliability and replicability of Approaches to Study Questionnaires. Studies in Higher Education, 15, 155-168.

Science teaching reconsidered. (1997). Washington, DC: National Academy Press.

Wilkerson, L. & Gijelaers, W. H. (Eds.). (1996). Bringing problem-based learning to higher education: theory and practice: New directions for teaching and learning, No. 68. San Francisco: Jossey-Bass.

Linda C. Hodges, Princeton University, NJ Lilia C. Harvey, Agnes Scott College, GA

Linda is the Associate Director of the McGraw Center for Teaching and Learning. Formerly the Kenan Professor of Chemistry at Agnes Scott College, in 1999 she was named as a Carnegie Scholar of the Pew National Fellowship Program. Lilia is an Associate Professor of Chemistry, and an active member of the Project Kaleidoscope Faculty for the 21st Century group with interests in reforming undergraduate science education.