A Chalkboard for a Canvas By Debra Cleveland Although mining and teaching biology appear wholly unrelated, plant physiologist Robert Thornton sees an analogy between the two. "The deeper you dig in a mine," he says, "the more time and energy it takes to get people to its face, where mining takes place. Similarly, biology is advancing so rapidly that it takes increasingly more time and resources to get students to a place where they have the tools to make their own creative contributions to science. This is why we need the best minds in science thinking about how to teach biology." Over the course of his 34-year UC Davis career, Thornton, who retired this spring from the Section of Plant Biology, has devoted much time to thinking about how to teach biology. According to him, teachers do the most good when they improve a student's general thinking skills. "I see the teacher's role as providing incentive to students," says Thornton, "diagnosing their learning weaknesses, and prescribing a way to overcome their weaknesses." A highly regarded instructor of the division's introductory biological sciences courses, Thornton's initial aspiration was not to become a teacher or a scientist. In fact, his family's economic circumstances made attending college unlikely. He grew up in the small town of Ophir, in the Sierra Nevada foothills. "My family was extremely poor," he says. "We lived in a shack without electricity and didn't have indoor plumbing until I was in elementary school." Despite his family's poverty, Thornton dreamed of becoming an aeronautical engineer. "I had an uncle who was a fighter pilot in World War II," he says, "and he was my hero. I wanted to be like him and fly airplanes; I was absolutely desperate to fly airplanes. So I thought I'd be an aeronautical engineer, and design airplanes and then fly them." The young Thornton voraciously read Air Trails, an aeronautical magazine, and pored over advertisements for aeronautical trade schools in the back of the magazine. He was determined to attend one of these trade schools, but someone, he doesn't recall whom, suggested that he apply to the California Institute of Technology, Pasadena. Says Thornton, "My father-who installed linoleum for a living- had wanted to go to Cal Tech but couldn't because of the Depression. I applied, got in, and went with the intention of studying aeronautical engineering." Thornton later found out that Cal Tech admitted him as part of a program to bring to the school students who had scored highly on the verbal part of the Scholastic Aptitude Test. "Cal Tech thought they might be missing out on some talent by admitting only those students who scored highly on the mathematical and scientific parts of the exam," Thornton says. Going from home to Cal Tech was not an easy transition. "My background was very different from most of the other students'-their fathers were lawyers and doctors-so it was quite an ordeal. I got extremely homesick," he says. Thornton remembers that he and a hometown friend, who had also come to Cal Tech, went to a phone booth and took turns calling their parents, telling them they wanted to come home. "My friend's parents told him to come home and mine told me to stay," says Thornton. "Perhaps that made all the difference because my friend never did finish college." In addition to feeling out of place, Thornton discovered that he didn't have the mathematical facility required to become an aeronautical engineer. By process of elimination, he ended up majoring in biology. "I considered everything," he says, "For example, I thought about geology as a major but noticed that the geologists appeared to be gregarious people. I was much more of an introvert and so decided against being a geology major." As it turned out, Thornton found he had a talent for biology and thrived in the discipline. Toward the end of his undergraduate years, a Cal Tech professor suggested to Thornton that he go to Harvard for graduate study. He was stunned by the suggestion but then thought Why not? Thornton enrolled at Harvard as a doctoral student, but after completing the requirements for a master's degree in biology, he left. "My wife at the time-I had gotten married at the end of my sophomore year at Cal Tech-didn't like science or being on the East Coast," says Thornton, "and one day she asked if I was going to finish the graduate program. She made me realize I had a choice, and we decided to move back to the West Coast." Thornton and his wife subsequently moved to Ojai, where he had his first teaching experience. "After working for an engineering firm," says Thornton, "I taught at a private school in Ojai for a couple years. I taught all sorts of things, from the junior high to college level." At this point in his life, Thornton says he had a "learning epiphany." It was a revelation that provided the foundation of his teaching philosophy. "One day I was unpacking materials for a chemistry class," he says, "and realized I was homesick for the academic community at Harvard. So I decided to go back, but to re-apply I had to take the GRE (Graduate Record Exam). I had always found math difficult, but I suddenly discovered you could look at problems more than one way. I realized that had I been taught differently, I might have been very good at math. I still don't know what caused this epiphany; it could simply have been maturation, or perhaps teaching math." Out of that experience, Thornton developed his 'logjam theory' of learning. "Your mental facility is like a river, with ideas flowing instead of water," he explains, "But a logjam can occur: ideas get tangled up and prevent the river from flowing. In a logjam, however, there's one key log, and if you get that one log loose, the whole thing breaks up. So I conjectured that a key concept had created a logjam for me and now something had happened to unlock that. Later when I was teaching, I thought this might be the case with other people-that when they have difficulty with thinking skills, they have a logjam. If we can find the key idea, we can open it up and they'll become great thinkers. This philosophy has animated my whole teaching career." Thornton returned to Harvard and received his Ph.D. in 1966. In 1968, the recently divorced Thornton came to UC Davis and began teaching introductory biological sciences courses. Says Thornton, "I put a lot of creative energy into the job. I wanted students to have more 'wow' experiences such as I had had when re-taking the GRE." In 1975 Thornton received the Academic Senate's Distinguished Teaching Award, specifically for his superlative lectures. However, he felt his teaching methods needed refining. "Often when I was teaching," says Thornton, "I felt as though I was leading a pack of people up a mountain for a great view, but when I got to the top and said voilà, I didn't hear any exclamations because people were straggled out behind me. So I began to experiment with teaching methods. I administered a difficult conceptual exam and afterward interviewed students about their thinking processes. I discovered students don't connect things enough." Consequently, Thornton made connecting concepts the primary focus of his classes. He shifted course materials to problem-based learning and designed instruction around exams. "My exams are the dread of students because I ask a lot of questions that begin 'Which answer helps most to explain….'" An early proponent of computer-based instruction, Thornton has found that computers can aid instruction, but aren't effective replacements for a human. When he used computerized presentations entirely for a class, instead of lecturing, course ratings were significantly lower. "I concluded," says Thornton, "that students get something from a live instructor. They want to see someone at the chalkboard doing things, making mistakes." He did find that students love self-tests, for which computers are useful. "Also," says Thornton, "students often can't visualize what you're trying to put in front of them. With computers, you can create animated simulations." Thornton's artistry as a teacher was reflected in the excellent evaluations students gave him, and he sees himself fundamentally as an artist. "I was famous for carrying around an eraser that cleared the clutter off the chalkboard," he says. "As I was erasing the board before beginning a lecture, I felt like an artist setting up a canvas." Although Thornton won't be creating biological portraits for students in person any more, his devotion to teaching is continuing into his retirement, which he is enjoying with his wife of 30 years. "I'll now have more time for developing computer simulations of biological processes, which are extremely complicated and time consuming," he says.