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EDUCATIONAL EXPERIMENTS
1 Angelo State University, Biology Department, San Angelo 76909
2 The University of Texas at Austin, Science Education Center, Austin, Texas 78712
Abstract
This study investigated discovery learning pedagogy and its effects on students’ achievement and attitudes toward instruction in a lower-division biology course, entitled Structure and Function of Organisms. Instruction was primarily lecture-based but included four discovery learning activities. Results indicate that students had greater achievement on content learned through discovery methods than lecture-based instruction. Findings regarding students’ attitudes toward discovery-based instruction suggest that students enjoyed active, discovery-based problems, believed that discovery helped them gain an understanding of the material and helped them to develop skills that could be used in other courses. The study presented here shows that a moderate amount of discovery learning used in combination with traditional methods of instruction may be an effective means for promoting students’ achievement.
Key words: discovery-based instruction
Discovery learning most often refers to pedagogy that exposes students to various situations, questions, or tasks that allow them to "discover" for themselves the intended concepts or material (1). Learning occurs when the learner constructs an understanding of newly discovered information by associating it with prior knowledge in an organized and systematic way. Within this context, discovery learning is defined as student-based exploration of an authentic problem using the processes and tools of the discipline. Discovery learning in its many forms has been recommended as a means for instruction by major science education organizations (4, 13, 14). Research has demonstrated the potential benefits of active/discovery learning over traditional, passive learning (2, 21). Specific benefits of discovery learning include learner involvement yielding more and different ways for the learner to experience the content, student activity, which increases attention to task(s) and creation of an episodic memory that aids reconstruction of knowledge, meaningful learning that involves deeper processing of ideas and confronting misconceptions, and higher-level learning, so that science is viewed as a dynamic process, not simply a static set of facts (3, 20). The meaningful experiences provided by discovery learning result in students who are motivated, self-directed learners that may be better able to learn and recall information (15, 20).
Discovery learning has long been advocated as a means for science instruction at the elementary and secondary level, but it is just beginning to make in-roads into postsecondary settings. Within this context, it is viewed as an effective means for improving student achievement and developing science process skills by directly involving students in the learning process, resulting in more meaningful learning, which, in turn, leads to increased motivation and improved student attitudes (2, 20). The research presented here focuses on an instructors’ use of discovery learning strategies in conjunction with traditional, didactic instruction.
This study has important implications for instructors of science, who often report student content acquisition (i.e., covering the content) as their primary goal (5, 7, 10). If the limited use of discovery learning in combination with more traditional practices can improve students’ achievement, science faculty should consider reevaluating their current teaching strategies. The combination of discovery and traditional pedagogy in this study is offered as a means for allowing students to become involved in the inquiry process of science, therefore improving college science instruction while allowing instructors to still "cover the content" in a style with which they are familiar and comfortable.
The purpose, therefore, of this study was to gain an understanding of the aspects and influencing factors of discovery learning that impact student achievement and attitudes within the context of a college level, undergraduate biology course. The course studied consisted of two semester-long (15 wk) sections of sophomore level biology, entitled the Structure and Function of Organisms. Each section was taught by the same instructor, had similar numbers of students (
160 each), and used similar exams. The course was primarily lecture-based interspersed with Socratic-type questioning episodes and taught in a large lecture hall. In addition, four discovery learning activities were used during the semester. The discovery activities (see APPENDIX A) were designed to teach students about the process of science and experimental design, while introducing or reinforcing course content. After undergoing an introductory lecture segment, students spent the remainder of the class, (15–20 min) working in informal groups of three or four, formulating hypotheses based on lecture material, and designing experiments to test the hypotheses. Data sets based on work published in peer reviewed journals were made available to the groups, which they then had to graph, analyze, and interpret. These analyses then served as the bases from which students made predictions about related topics. The subject matter covered via discovery learning in this course were stomatal control, osmosis, hormonal control of tropism, and transport in red blood cells. The focus of the research presented here was to explore students’ attitudes toward discovery-based instruction and the impact of discovery-based instruction on student achievement.
INSTRUMENTS AND METHODS
Achievement.
Achievement was assessed using a comprehensive final exam that included both content and process elements of the discovery activities. The final exam was subdivided into categories based on the types of questions that were asked (see APPENDIX B). The categories were defined as content learned through traditional lecture methods, content learned through discovery methods, discovery (science) process skills, and experimental design questions. Three experts with advance degrees in biology1 determined that the questions contained in the categories were comparable in level of difficulty. Descriptive statistics were determined for each student’s performance in each category and compared using a ANOVA. Regression analysis was performed on adjusted scores to determine whether the categories were indicative of overall final exam performance. Partial correlation coefficients were used to determine which category was the strongest indicator of final exam performance. Lastly, a correlation was performed between the final exam scores and the posttest attitude survey to determine the relationship between the two.
Attitude toward instruction.
Students’ attitudes toward discovery instruction were determined using an anonymous, posttest-only survey given at the end of the semester. The survey contained four items describing students’ attitudes toward discovery instruction on a Likert-type scale in addition to student’s prediction of their final grade in the class. Descriptive statistics and frequency distributions were collected. Correlation analyses were performed to determine whether there was a relationship between students’ attitudes toward instruction and their predicted final grade in the course.
RESULTS
Achievement.
The students’ performance on the final exam was evaluated to determine the effectiveness of the discovery instruction on students’ content acquisition, science process skills, and experimental design capabilities. Corrected means, adjusted for varying point values on the categories, indicate that students performed best on those content questions learned through discovery methods and worst on experimental design questions learned through discovery methods (Table 1).
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Achievement.
The majority of the course was taught by traditional lecture methods, so it stands to reason, given that the questions within the different categories of the final exam were equally difficult, that students would perform best on questions that dealt with content presented through lecture. However, this was not the case. The results of this study indicate that students exhibited greater achievement on content-based questions learned by discovery and questions demanding the use of discovery process skills than on questions based solely on content learned through lecture. These findings support the hypothesis that student involvement in discovery learning would result in higher achievement in science content knowledge. These findings are especially important given the inconsistent findings within the research literature (e.g., compare Refs. 6 and 9).
One reason why discovery learning may improve student achievement is because instead of only lower level recall of factual information, it promotes higher-level thinking skills (e.g., application, analysis, synthesis, and evaluation). This higher-level thinking may have led to better student understanding of the discovery-based content and may explain the higher scores on the discovery content portion of the exam (vs. content learned through didactic means). This is further substantiated by the finding that performance on discovery-based content questions and lecture-based content within the final exam are most predictive of final exam score.
Other possible explanations for the increased achievement are that discovery learning increases student attention to task(s) at hand and creates an episodic memory that aids in reconstruction of knowledge. Student involvement in the discovery learning process (i.e., attention to task) "forces" them to struggle with the content and processes of science at the moment of instruction. This immediacy causes students to try to understand material and reconcile any cognitive dissonance in the classroom, at the moment of instruction, and not at a later date. Discovery learning promotes an episodic memory in which information is associated with specific events. Students can use recollections of the discovery activity itself to reconstruct the knowledge gained through the activity. Discovery activities used in this course may have contributed to the increase in student achievement based on these premises.
Perhaps the greatest effect of discovery learning is that it provides students with meaningful experiences, promoting meaningful learning. Researchers assert that meaningful experiences result in students who are motivated, self-directed learners that may be better able to learn and recall information (15, 20). With discovery, students learn in authentic contexts that can lead to curiosity and positive attitudes (20). In addition, discovery learning promotes meaningful learning. By involving the learner, discovery learning gives him/her more and different ways to experience the content, making it more meaningful and resulting in better recall of information (20). Discovery activities place content into context, which may have given students in this study the meaning they needed to make appropriate connections and therefore account for the increase in student achievement.
However, we must also acknowledge the most obvious, parsimonious explanation of the increased achievement scores, students’ "time on task." More specifically, students may have scored better on discovery content material because, in addition to receiving a lecture on the information and possibly studying it outside of class, students performed activities using that information. The discovery activities provided students with opportunities to read, write, apply, listen, discuss, and reflect on the content and processes of the topics they were studying. It is well documented that writing, discussing, and sharing ideas, solving problems, and applying knowledge increases the tendency of students to retain knowledge (10, 17, 22). However, this alternative hypothesis does not discredit discovery learning but strengthens it. Pedagogies that allow students to focus attention on the critical tasks at hand, think about the content, and apply science content skills, resulting in increased content knowledge, should be the basis of every course. Discovery learning is one such pedagogy that, when used modestly in conjunction with traditional didactic instruction, increases student achievement.
Surprisingly, students in this study received the lowest scores on questions pertaining to experimental design, on which the discovery activities were based. Although students participated in the discovery process, perhaps they did not recognize the designing of experiments as important relative to the outcomes or content learned through the experiments. As a result, students may not have devoted time to studying experimental design, instead focusing on content. Although at this point, we can only speculate as to the reason why students scored well on those exam questions pertaining to discovery content and science process but paradoxically failed to perform well on questions pertaining to experimental design. Further study is required to clarify this seeming contradiction.
Attitude toward instruction.
This study also hypothesized that students would come to appreciate discovery learning and value it as an effective means for enhancing their learning. In support of the hypotheses, data suggest that students in this course liked the active, discovery-based problems, believed that discovery helped them gain an understanding of the material presented in this class, and, through discovery activities, developed skills that could be used in other courses. The improved understanding of material and decided course approval reported by students mirrors the results of earlier analyses (3, 6, 18).
Success, in terms of students’ appreciation of discovery learning may be due in large part to the melding of discovery activities and lecture. Researchers report that courses dominated by discovery and active-learning strategies can lead to poor student attitudes (16, 19). In the course studied here, discovery activities were used sparingly throughout the semester. The limited number of activities used in combination with traditional lecture-based instruction may have been a contributing factor to students’ approval of discovery learning.
Students’ positive views of discovery learning are of particular importance given the context of this study. Discovery learning activities were performed successfully in a large lecture hall without sacrificing the amount of content covered, a common criticism of active instruction such as discovery learning (3). To be successful in a large class, activities must be highly structured (11). That these activities were structured and embedded within lecture may account for their success. Students expect faculty to lecture, so lecture cannot be totally abandoned in favor of a strictly activities-based course unless the activities are gradually implemented over time and students recognize the activities as an integral part of the learning process (12, 16). In the context of this course, students enjoyed and valued participating in the discovery learning activities that gave them experience with processes of science.
CONCLUSION
As evidenced by several national and regional efforts, colleges are striving to improve teaching and learning. Part of this effort involves striving toward goals identified by national science reform efforts (e.g., American Association for the Advancement of Science, Science for All Americans) that include understanding the scientific method and developing scientific habits of mind. For many instructors, departments, and campuses, active discovery learning is viewed as an effective means for implementing science process into a curricula that has traditionally emphasized recall of factual information. The study presented here shows that a moderate amount of discovery learning used in combination with traditional methods of instruction may be an effective means for promoting students’ achievement. Furthermore, when used conservatively students appreciate the value of discovery learning.
APPENDIX A
Discovery Learning Example
In this discovery activity concerning stomatal control, students divide up into informal groups to work on designing an experiment that teaches and reinforces science process skills. Students are given prior information on experimental design and stomatal anatomy and control via lecture and handouts. The activities are graded as part of an "in-class" exercise and calculated into the students’ final grade. At the end of the activity, random groups are asked to present their experiment to the rest of the class. The following is from the discovery activity regarding stomatal control.
Directions For the Group Activity
Parts A-C; follow underlined directions on your group answer sheet.
Part A.
What aspect of stomatal control do you wish to investigate? Decide on your independent variable (some event in the hypothesized pathway) and which dependent variable, either stomatal aperture or rate of stomatal conductance (same as transpiration rate) you wish to investigate.
Answer 1–6 on the group answer sheet. Then, get a data set that is appropriate to your proposed measurement. The data sets on the pink sheets are taken from published research articles.
Part B.
Graph your data on the form provided. Place the independent variable (test variable) on the horizontal axis and the dependent variable on the vertical axis. Label the axes of the graph. Graph data points using points ( · ) or circles (
).
Answer 7–8 on the group answer sheet.
Part C.
What you have is a set of measurements that indicates whether or not a relationship exists between your independent and dependent variables. This is one set of observations, but you need to perform an experiment in order to test the mechanism of stomatal control.
Perform an imaginary experiment. What would be the effect of a specific manipulation on guard cell function? Choose an experimental manipulation, such as A-E below, and predict how your curve would differ if the manipulation were done at about the midpoint of your graph.
Sample substances to add in your manipulation:
On your graph: indicate with an arrow along the x-axis the point at which you make the manipulation. Predict the results by graphing hypothetical values of the dependent variable as "X" points on the graph.
Answer 9–11 on the group answer sheet
In-Class Exercise
Print names in your group: _______________________________
Part A.
Part B (on graph paper).
Part C.
APPENDIX B
Content-Based Questions Taught by Lecture
Content-Based Questions Taught by Discovery
Discovery Process-Based Question
Experimental Design-Based Question
Footnotes
Address for reprint requests and other correspondence: R. R. Wilke, Angelo State Univ., Biology Dept., San Angelo, TX 76909.
1 All three experts were faculty of The University of Texas at Austin. Each expert possessed a Ph.D. in zoology and had at least 15 years of teaching experience with various lower and upper level physiology courses at the collegiate level. 
Received for publication April 6, 2000. Accepted for publication January 18, 2001.
REFERENCES
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