Peer instruction enhanced student performance on qualitative problem-solving questions
http://www.100md.com
《生理学进展》医学期刊
1 Cátedra de Fisiología, Facultad de Ciencias Veterinarias, Universidad Nacional de La Plata, La Plata, Argentina
2 Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan
Address for reprint requests and other correspondence: S. E. DiCarlo, Wayne State Univ. School of Medicine, 540 E. Canfield Ave., Detroit, MI 48201 (e-mail: sdicarlo@med.wayne.edu)
Abstract
We tested the hypothesis that peer instruction enhances student performance on qualitative problem-solving questions. To test this hypothesis, qualitative problems were included in a peer instruction format during our Physiology course. Each class of 90 min was divided into four to six short segments of 15 to 20 min each. Each short segment was followed by a qualitative problem-solving scenario that could be answered with a multiple-choice quiz. All students were allowed 1 min to think and to record their answers. Subsequently, students were allowed 1 min to discuss their answers with classmates. Students were then allowed to change their first answer if desired, and both answers were recorded. Finally, the instructor and students discussed the answer. Peer instruction significantly improved student performance on qualitative problem-solving questions (59.3 ± 0.5% vs. 80.3 ± 0.4%). Furthermore, after peer instruction, only 6.5% of the students changed their correct response to an incorrect response; however, 56.8% of students changed their incorrect response to a correct response. Therefore, students with incorrect responses changed their answers more often than students with correct responses. In conclusion, pausing four to six times during a 90-min class to allow peer instruction enhanced student performance on qualitative problem-solving questions.
Key words: collaboration; meaningful learning; transfer
Introduction
THERE HAS BEEN REMARKABLE PROGRESS in our understanding on how people learn. It is now clear that concept construction requires active processing of information. That is, we understand and remember the information we think about (8)! However, processing information requires time. Faculty members must be realistic about the amount of time required to learn complex concepts and provide the time needed to achieve the goal (5). Students need time to explore the underlying concepts and to generate connections to other information. Students must have time to "grapple" with specific information relevant to the topic. Thus, learning cannot be rushed; the complex cognitive activity of information integration requires time (4).
However, students attending our Physiology course are in class 5 h/wk. This computes to 2.4% of the total hours in a student's week. Herein lies the problem: How do we provide time for information processing during this limited class time (8) One way is to use qualitative problems (14, 15) in a peer instruction format (12, 13). These problems require a qualitative prediction (increase/decrease/no change) about the response of a physiological system to a perturbation. Qualitative problems require integration of multiple concepts; however, the problems can be answered quickly with single, best multiple-choice questions. These are important considerations because one of the most important factors influencing learning is what the student already knows. The students must link new information to concepts they already possess (8). This process is critical for solving novel problems. Peer instruction is a cooperative learning technique that may promote this process. Therefore, we tested the hypothesis that peer instruction enhances the students' performance on qualitative problem-solving questions. To test this hypothesis, qualitative problems were included in a peer instruction format during our Veterinary Physiology course.
METHODS
Design.
We borrowed concepts from Lymna (11) and Mazur (13) peer instruction activities to promote student involvement in the learning process and test the hypothesis that peer instruction enhances student performance on qualitative problem-solving questions.
Procedures.
This peer instruction, active-learning technique was implemented during the Physiology class (Fisiología No. 423) at the Facultad de Ciencias Veterinarias, Universidad Nacional de La Plata, La Plata, Argentina. The class consisted of 114 veterinary medical students. The class was lecture based, and the peer instruction technique was used for 10 classes involving cardiovascular, respiratory, and renal physiology. Each class of 90 min was divided into four to six short presentations of 15–20 min each. Each short presentation was followed by a qualitative problem-solving scenario that could be answered with a one-question, multiple-choice quiz. All students were allowed 1 min to think and to record their answers. Subsequently, students were allowed 1 min to discuss their answers with classmates (2–3 students/group). Students were then allowed to change their first answer if desired, and both answers were recorded. Students were instructed to provide reasons for their answers and to convince their peers that their answers were correct. In this format, the students had two roles: as a teacher, explaining the rationale for their answer; and as a student, listening to the reasoning for their peers' answer. Finally, the instructor and students discussed the answer.
The questions were qualitative problem-solving scenarios generated by M. J. Giuliodori using the format provided by Michael and co-workers (see Appendixes A–C) (14, 15). The qualitative problem-solving scenarios asked for a qualitative prediction (increase/decrease/no change) about the response of a system to a perturbation; for example, If the heart is denervated, what change, if any, will occur to heart rate (will it increase, decrease, or stay the same) (14). Specifically, the questions posed conceptual problem-solving scenarios that required the integration of multiple concepts but were answered with single, best multiple-choice questions. In addition, tables were used, instead of multiple-choice questions, when more than one prediction was required (see Appendixes A–C); for example, Predict how cutaneous blood flow, shivering, and sweating will be affected at the onset of a fever (15).
Statistical analysis.
All results are presented as means ± SE, and significance was set at the P < 0.05 level. To determine the effect of peer instruction on student performance on qualitative problem-solving questions (see Fig. 1), we used a Student's paired t-test to compare responses obtained when the students solved problems as individuals with responses obtained when the students solved problems in collaboration with peers (peer instruction).
To determine which students changed their individual response (see Fig. 2), we used a Kruskal-Wallis nonparametric, one-way ANOVA. Once statistical significance was established, post hoc analysis was performed with a Student-Newman-Keuls test. Finally, to compare the positive effects (individual incorrect responses changed to peer-instructed correct responses) with negative effects (individual correct responses changed to peer-instructed incorrect responses), we used a Mann-Whitney rank-sum test (see Fig. 3). Significance was set at the P < 0.05 level.
RESULTS
Students' perceptions regarding the peer instruction activity are presented in Table 1. One hundred four students (of 114 students total) returned the completed questionnaire (91.2% response rate). The students reported that the peer instruction methodology was simple and helped them to better understand the topics. The students reported that the level of discussion was high and the immediate feedback was helpful. Finally, the students enjoyed the methodology and recommended it for other courses.
DISCUSSION
In this work, we examined the effect of peer instruction, a pedagogical tool that increases student interactions with each other and with the instructor, on student performance on qualitative problem-solving questions. The main finding was that peer instruction increased student performance on qualitative problem-solving questions. Specifically, there was a 35% improvement in correct responses to qualitative problems after discussions with peers (absolute gain: 21 percentage units, P < 0.001; Fig. 1). Similar results have been reported by other investigators. For example, Crouch and Mazur (7) observed significant increases in conceptual problem-solving skills involving physics scenarios over a 10-yr period of peer instruction experience. Similarly, we (17) recently reported that peer instruction increased medical student performance on quizzes. Furthermore, collaborative testing, a similar peer instruction procedure, also increased medical student performance on quizzes (16, 18). Similarly, peer instruction as well as collaborative testing increased undergraduate student performance on exams and increased student retention of previously learned information (5, 6). Specifically, performances on quizzes and retention of previously learned information were significantly higher when students completed exams in groups rather than when they completed exams individually (5, 6). Importantly, we (5) also documented that peer instruction enhanced meaningful learning (the students' ability to solve novel problems).
The new finding from this study is that peer instruction enhanced student performance on qualitative problem-solving questions. Qualitative problems require the integration of multiple concepts. Thus, peer instruction provides a learning experience that leads to the ability to extend what has been learned in one context to new contexts (2, 20). All learning experiences can appear equivalent when measures of learning are focused on the ability to repeat previously taught facts. However, quality learning experiences require the ability to extend what has been learned in one context to new contexts. Quality learning experiences require time to allow for practice. Faculty members must be realistic about the amount of time required to learn complex concepts and provide the practice time to achieve the goal. Students need time to explore underlying concepts and to generate connections to other information. Students must have time to "grapple" with specific information relevant to the topic. Thus, learning cannot be rushed; the complex cognitive activity of information integration requires time (4). Importantly, peer instruction provides the time for students to test existing knowledge and apply it to novel situations in a safe, supportive environment. This quality learning experience allows students to evaluate their concepts and experiences while providing feedback about their progress.
A previous study (13) has shown that students obtain optimal benefits of peer instruction when the percentage of correct individual responses is between 35% and 70%. Specifically, when the percentage of correct individual responses is too low (<35%) or too high (>70%), there is little improvement. For example, when the percentage of correct individual responses is too low (<35%), most of the students have not obtained sufficient understanding of the concept to have meaningful discussions. In contrast, when the percentage of correct individual responses is too high (>70%), there is less room for improvement (13). In this study, the percentage of correct individual responses (59.3 ± 0.4%) was within the range for optimal improvement (13).
The beneficial effects of peer instruction are due, in part, to two major factors. First, student attention decreases with each passing minute during sustained lectures. Importantly, peer instruction activities increase attention by actively involving students in problem-solving activities. Furthermore, sustained lectures appeal only to auditory learners and tend to promote lower-level learning of factual information (10, 18). Finally, sustained lecturing assumes that all students learn the same information at the same pace (9). Rowe (19) reported that pausing every 15 min during a lecture increased students' attention and retention.
Second, the value of peer instruction derives from the student generating explanations for their answers. Students obtain benefits when they generate their own explanations ("self-explanation") for their new knowledge (3) and when they explain their reasoning to classmates, that is, when the learner acts as a teacher. Thus, "the best way to learn something is to teach it," because teaching requires the generations of explanations, both for oneself and for the learner (14). All of us who teach have experienced and understand the true meaning of this concept.
In this study, only 6.5% of the students with individual correct responses changed their answers after peer discussion to incorrect responses. In sharp contrast, 64.1% of the students with individual incorrect responses changed their answers after peer discussion. Thus, most of the students who changed their responses changed to a correct answer to correct responses (56.8%), whereas a small portion changed to an incorrect answer (7.3%, P < 0.05; Fig. 2). Specifically, 22.4% of the student population changed their responses in a positive way (from incorrect to correct answers), whereas only 4.0% of the student population changed their responses in a negative way (from correct to incorrect answers, P < 0.001; Fig. 3). Taken together, the magnitude of the peer instruction positive effect was 5.6 times higher than the magnitude of the peer instruction negative effect. Therefore, the beneficial effects of peer instruction on students' performance were observed in the group of students having individual incorrect answers ("weaker students") (Fig. 3). These results are in agreement with reports by Crouch and Mazur (7). These authors reported that it is much easier to change the mind of someone who is wrong than it is to change the mind of someone who has selected the correct answer for the right reasons (13). Thus, there is always an increase and never a decrease in the number of correct answers (solutions) after discussion with classmates.
Faculty members are often reluctant to incorporate active learning activities in class. The reasons most often advanced for not including these active learning activities include not being able to cover as much content and the excessive preparation time required for devising strategies promoting active learning (1). However, as stated by Mazur (13), using time for peer instruction greatly improves the student's level of understanding with relatively little effort and no capital investment. In addition, the instructor has several important roles during the process. For example, the instructor must model appropriate social skills, including listening and providing constructive feedback or eliciting more indepth responses through probing questions. The instructor must also reinforce these positive behaviors by publicly commenting on the ways students use them effectively (5).
Student perceptions regarding the peer instruction activities are in agreement with previous work (5, 6, 16, 17). Students appreciated the interactions with peers and with the instructor. This interaction provided immediate feedback, which is not possible during the traditional lecture format. The students reported that peer instruction facilitated their learning of the topics. In this content, students were seen to be enthusiastically engaged in content-based discussions, giving support to their choices. Finally, students enjoyed this learning experience and recommended it for other courses.
In conclusion, pausing four to six times during a 90-min class to allow peer instruction of qualitative problems enhanced the students' performance on qualitative problem-solving questions.
Appendix A: Samples of Assessed Cardiovascular Questions
1. Predict (increase/decrease/no change) what would happen to the velocity of blood flow through systemic vessels if you provide a medication causing smooth muscle contraction:
Increase (correct)
Decrease
No change
2. Predict (increase/decrease/no change) what would happen to the resting membrane potential in cardiac muscle cells if the extracellular K+ concentration increases:
Increase
Decrease (correct)
No change
3. Predict (increase/decrease/no change) what would happen to cardiac output if you provide a medication causing smooth muscle relaxation:
Increase
Decrease (correct)
No change
4. Predict (increase/decrease/no change) what would happen to stroke volume, end-diastolic volume, and cardiac output if afterload increased:
5. Predict (increase/decrease/no change) what would happen to the volume of blood returning to the heart through the veins if right atrial pressure (central venous pressure) increased:
Increase
Decrease (correct)
No change
6. Predict (increase/decrease/no change) what would happen to tissue fluid formation if you provide a medication causing smooth muscle contraction in veins:
Increase (correct)
Decrease
No change
Appendix B: Samples of Assessed Respiratory Questions
1. Predict (higher/lower/the same) how the tidal volume of a horse immediately after a race would compare with its tidal volume at rest:
Higher (correct)
Lower
The same
2. Predict (increase/decrease/no change) what will be the effect on alveolar ventilation of breathing at higher frequency while keeping the same respiratory volume:
Increase
Decrease (correct)
No change
3. Predict (increase/decrease/no change) what would happen to functional residual capacity in a lung disease leading to emphysema:
Increase (correct)
Decrease
No change
4. Predict (increase/decrease/no change) what would happen to airflow resistance if you provide a medication causing smooth muscle relaxation:
Increase
Decrease (correct)
No change
5. Predict (increase/decrease/no change) what would happen to arterial PO2 in a dog breathing 100% oxygen (oxygen therapy):
Increase (correct)
Decrease
No change
6. Predict (increase/decrease/no change) what would happen to ventilation and perfusion in a dog having its right pulmonary artery blocked:
Appendix C: Samples of Assessed Renal Questions
1. Predict (increase/decrease/no change) what would happen to the glomerular filtration rate, renal blood flow, and glomerular capillary pressure during efferent arteriolar vasoconstriction:
2. Predict (higher/lower/the same) how urine osmolarity would be compared with plasma osmolarity if you provide a medication blocking the 2Cl–-Na+-K+ cotransporter (i.e., furosemide):
Higher (correct)
Lower
The same
3. Predict (higher than 1/lower than 1/equal to 1) the fractional excretion of a drug that is both filtered and secreted (with no reabsorption).
Higher than 1 (correct)
Lower than 1
Equal to 1
4. Predict (increase/decrease/no change) what would happen to the urine concentration capacity in a dog given a low-protein diet:
Increase
Decrease (correct)
No change
5. Predict (increase/decrease/no change) what would happen to plasma Na+ concentration, total body Na+ content, plasma K+ concentration, and total body K+ content if you provide a medication with an aldosterone antagonistic effect:
6. Predict (increase/decrease/no change) what would happen to urine elimination of tritratable acids if the organic load of metabolic acids increases:
Increase (correct)
Decrease
No change
7. Predict (increase/decrease/no change) what would happen to both the volume and osmolarity of extra- and intracellular fluid compartments if you provide a hypertonic saline solution (i.e., 7.5% NaCl) intravenously:
GRANTS
This work was supported, in part, by The American Physiological Society Teaching Career Enhancement Award (to M. J. Giuliodori).
REFERENCES
Bonwell C and Eison J. Active Learning: Creating Excitement in the Classroom. Washington, DC: George Washington Univ. Press, 1991.
Byrnes JP. Cognitive Development and Learning in Instructional Contexts. Boston, MA: Allyn and Bacon, 1996.
Chi M, de Leeuw N, Chiu M, and La Vancher C. Eliciting self-explanations improves understanding. Cogn Sci 18: 439–477, 1994.
Committee on Developments in the Science of Learning, Committee on Learning Research and Educational Practice, and National Research Council. How People Learn: Brain, Mind, Experience and School. Washington, DC: National Academy Press, 2000.
Cortright RN, Collins HL, and DiCarlo SE. Peer instruction enhanced meaningful learning: ability to solve novel problems. Adv Physiol Educ 29: 107–111, 2005.
Cortright RN, Collins HL, Rodenbaugh DW, and DiCarlo SE. Student retention of course content is improved by collaborative-group testing. Adv Physiol Educ 27: 102–108, 2003.
Crouch C and Mazur E. Peer instruction: ten years of experience and results. Am J Physics 69: 970–977, 2001.
DiCarlo SE. Cell biology should be taught as science is practised. Nat Rev Mol Cell Biol 7: 290–296, 2006.
Johnson D, Johnson R, and Smith KA. Active Learning: Cooperation in the College Classroom. Edina, MN: Interaction Book, 1991.
Lujan HL and DiCarlo SE. First-year medical students prefer multiple learning styles. Adv Physiol Educ 30: 13–16, 2006.
Lymna F. The responsive classroom discussion. In: Mainstreaming Digest, edited by Anderson AS. College Park, MD: Univ. of Maryland College of Education, 1981.
Mazur E. Peer Instruction: a User's Manual. Upper Saddle River, NJ: Prentice Hall, 1997.
Mazur E. Peer instruction: getting students to think in class. Proc ICUPE 399: 981–988, 1997.
Michael J and Modell H. Active Learning in Secondary and College Classrooms: a Working Model for Helping the Learner to Learn. Manwah, NJ: Erlbaum, 2003.
Michael J and Rovick A. Problem Solving in Physiology. Upper Saddle River, NJ: Prentice Hall, 1999.
Rao SP, Collins HL, and DiCarlo SE. Collaborative testing enhances student learning. Adv Physiol Educ 26: 37–41, 2002.
Rao SP and DiCarlo SE. Peer instruction improves performance on quizzes. Adv Physiol Educ 24: 51–55, 2000.
Rao SP and DiCarlo SE. Active learning of respiratory physiology improves performance on respiratory physiology examinations. Adv Physiol Educ 25: 55–61, 2001.
Rowe M. Pausing principles and their effects on reasoning in sciences. In: Teaching the Sciences: New Directions for Community Colleges, edited by Brawer F. San Francisco, CA: Jossey-Bass, 1980.
Thorndike EL and Woodworth RS. The influence of improvement in one mental function upon the efficiency of other functions. Psychol Rev 8: 247–261, 1901.(Mauricio J. Giuliodori1, Heidi L. Lujan2)
2 Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan
Address for reprint requests and other correspondence: S. E. DiCarlo, Wayne State Univ. School of Medicine, 540 E. Canfield Ave., Detroit, MI 48201 (e-mail: sdicarlo@med.wayne.edu)
Abstract
We tested the hypothesis that peer instruction enhances student performance on qualitative problem-solving questions. To test this hypothesis, qualitative problems were included in a peer instruction format during our Physiology course. Each class of 90 min was divided into four to six short segments of 15 to 20 min each. Each short segment was followed by a qualitative problem-solving scenario that could be answered with a multiple-choice quiz. All students were allowed 1 min to think and to record their answers. Subsequently, students were allowed 1 min to discuss their answers with classmates. Students were then allowed to change their first answer if desired, and both answers were recorded. Finally, the instructor and students discussed the answer. Peer instruction significantly improved student performance on qualitative problem-solving questions (59.3 ± 0.5% vs. 80.3 ± 0.4%). Furthermore, after peer instruction, only 6.5% of the students changed their correct response to an incorrect response; however, 56.8% of students changed their incorrect response to a correct response. Therefore, students with incorrect responses changed their answers more often than students with correct responses. In conclusion, pausing four to six times during a 90-min class to allow peer instruction enhanced student performance on qualitative problem-solving questions.
Key words: collaboration; meaningful learning; transfer
Introduction
THERE HAS BEEN REMARKABLE PROGRESS in our understanding on how people learn. It is now clear that concept construction requires active processing of information. That is, we understand and remember the information we think about (8)! However, processing information requires time. Faculty members must be realistic about the amount of time required to learn complex concepts and provide the time needed to achieve the goal (5). Students need time to explore the underlying concepts and to generate connections to other information. Students must have time to "grapple" with specific information relevant to the topic. Thus, learning cannot be rushed; the complex cognitive activity of information integration requires time (4).
However, students attending our Physiology course are in class 5 h/wk. This computes to 2.4% of the total hours in a student's week. Herein lies the problem: How do we provide time for information processing during this limited class time (8) One way is to use qualitative problems (14, 15) in a peer instruction format (12, 13). These problems require a qualitative prediction (increase/decrease/no change) about the response of a physiological system to a perturbation. Qualitative problems require integration of multiple concepts; however, the problems can be answered quickly with single, best multiple-choice questions. These are important considerations because one of the most important factors influencing learning is what the student already knows. The students must link new information to concepts they already possess (8). This process is critical for solving novel problems. Peer instruction is a cooperative learning technique that may promote this process. Therefore, we tested the hypothesis that peer instruction enhances the students' performance on qualitative problem-solving questions. To test this hypothesis, qualitative problems were included in a peer instruction format during our Veterinary Physiology course.
METHODS
Design.
We borrowed concepts from Lymna (11) and Mazur (13) peer instruction activities to promote student involvement in the learning process and test the hypothesis that peer instruction enhances student performance on qualitative problem-solving questions.
Procedures.
This peer instruction, active-learning technique was implemented during the Physiology class (Fisiología No. 423) at the Facultad de Ciencias Veterinarias, Universidad Nacional de La Plata, La Plata, Argentina. The class consisted of 114 veterinary medical students. The class was lecture based, and the peer instruction technique was used for 10 classes involving cardiovascular, respiratory, and renal physiology. Each class of 90 min was divided into four to six short presentations of 15–20 min each. Each short presentation was followed by a qualitative problem-solving scenario that could be answered with a one-question, multiple-choice quiz. All students were allowed 1 min to think and to record their answers. Subsequently, students were allowed 1 min to discuss their answers with classmates (2–3 students/group). Students were then allowed to change their first answer if desired, and both answers were recorded. Students were instructed to provide reasons for their answers and to convince their peers that their answers were correct. In this format, the students had two roles: as a teacher, explaining the rationale for their answer; and as a student, listening to the reasoning for their peers' answer. Finally, the instructor and students discussed the answer.
The questions were qualitative problem-solving scenarios generated by M. J. Giuliodori using the format provided by Michael and co-workers (see Appendixes A–C) (14, 15). The qualitative problem-solving scenarios asked for a qualitative prediction (increase/decrease/no change) about the response of a system to a perturbation; for example, If the heart is denervated, what change, if any, will occur to heart rate (will it increase, decrease, or stay the same) (14). Specifically, the questions posed conceptual problem-solving scenarios that required the integration of multiple concepts but were answered with single, best multiple-choice questions. In addition, tables were used, instead of multiple-choice questions, when more than one prediction was required (see Appendixes A–C); for example, Predict how cutaneous blood flow, shivering, and sweating will be affected at the onset of a fever (15).
Statistical analysis.
All results are presented as means ± SE, and significance was set at the P < 0.05 level. To determine the effect of peer instruction on student performance on qualitative problem-solving questions (see Fig. 1), we used a Student's paired t-test to compare responses obtained when the students solved problems as individuals with responses obtained when the students solved problems in collaboration with peers (peer instruction).
To determine which students changed their individual response (see Fig. 2), we used a Kruskal-Wallis nonparametric, one-way ANOVA. Once statistical significance was established, post hoc analysis was performed with a Student-Newman-Keuls test. Finally, to compare the positive effects (individual incorrect responses changed to peer-instructed correct responses) with negative effects (individual correct responses changed to peer-instructed incorrect responses), we used a Mann-Whitney rank-sum test (see Fig. 3). Significance was set at the P < 0.05 level.
RESULTS
Students' perceptions regarding the peer instruction activity are presented in Table 1. One hundred four students (of 114 students total) returned the completed questionnaire (91.2% response rate). The students reported that the peer instruction methodology was simple and helped them to better understand the topics. The students reported that the level of discussion was high and the immediate feedback was helpful. Finally, the students enjoyed the methodology and recommended it for other courses.
DISCUSSION
In this work, we examined the effect of peer instruction, a pedagogical tool that increases student interactions with each other and with the instructor, on student performance on qualitative problem-solving questions. The main finding was that peer instruction increased student performance on qualitative problem-solving questions. Specifically, there was a 35% improvement in correct responses to qualitative problems after discussions with peers (absolute gain: 21 percentage units, P < 0.001; Fig. 1). Similar results have been reported by other investigators. For example, Crouch and Mazur (7) observed significant increases in conceptual problem-solving skills involving physics scenarios over a 10-yr period of peer instruction experience. Similarly, we (17) recently reported that peer instruction increased medical student performance on quizzes. Furthermore, collaborative testing, a similar peer instruction procedure, also increased medical student performance on quizzes (16, 18). Similarly, peer instruction as well as collaborative testing increased undergraduate student performance on exams and increased student retention of previously learned information (5, 6). Specifically, performances on quizzes and retention of previously learned information were significantly higher when students completed exams in groups rather than when they completed exams individually (5, 6). Importantly, we (5) also documented that peer instruction enhanced meaningful learning (the students' ability to solve novel problems).
The new finding from this study is that peer instruction enhanced student performance on qualitative problem-solving questions. Qualitative problems require the integration of multiple concepts. Thus, peer instruction provides a learning experience that leads to the ability to extend what has been learned in one context to new contexts (2, 20). All learning experiences can appear equivalent when measures of learning are focused on the ability to repeat previously taught facts. However, quality learning experiences require the ability to extend what has been learned in one context to new contexts. Quality learning experiences require time to allow for practice. Faculty members must be realistic about the amount of time required to learn complex concepts and provide the practice time to achieve the goal. Students need time to explore underlying concepts and to generate connections to other information. Students must have time to "grapple" with specific information relevant to the topic. Thus, learning cannot be rushed; the complex cognitive activity of information integration requires time (4). Importantly, peer instruction provides the time for students to test existing knowledge and apply it to novel situations in a safe, supportive environment. This quality learning experience allows students to evaluate their concepts and experiences while providing feedback about their progress.
A previous study (13) has shown that students obtain optimal benefits of peer instruction when the percentage of correct individual responses is between 35% and 70%. Specifically, when the percentage of correct individual responses is too low (<35%) or too high (>70%), there is little improvement. For example, when the percentage of correct individual responses is too low (<35%), most of the students have not obtained sufficient understanding of the concept to have meaningful discussions. In contrast, when the percentage of correct individual responses is too high (>70%), there is less room for improvement (13). In this study, the percentage of correct individual responses (59.3 ± 0.4%) was within the range for optimal improvement (13).
The beneficial effects of peer instruction are due, in part, to two major factors. First, student attention decreases with each passing minute during sustained lectures. Importantly, peer instruction activities increase attention by actively involving students in problem-solving activities. Furthermore, sustained lectures appeal only to auditory learners and tend to promote lower-level learning of factual information (10, 18). Finally, sustained lecturing assumes that all students learn the same information at the same pace (9). Rowe (19) reported that pausing every 15 min during a lecture increased students' attention and retention.
Second, the value of peer instruction derives from the student generating explanations for their answers. Students obtain benefits when they generate their own explanations ("self-explanation") for their new knowledge (3) and when they explain their reasoning to classmates, that is, when the learner acts as a teacher. Thus, "the best way to learn something is to teach it," because teaching requires the generations of explanations, both for oneself and for the learner (14). All of us who teach have experienced and understand the true meaning of this concept.
In this study, only 6.5% of the students with individual correct responses changed their answers after peer discussion to incorrect responses. In sharp contrast, 64.1% of the students with individual incorrect responses changed their answers after peer discussion. Thus, most of the students who changed their responses changed to a correct answer to correct responses (56.8%), whereas a small portion changed to an incorrect answer (7.3%, P < 0.05; Fig. 2). Specifically, 22.4% of the student population changed their responses in a positive way (from incorrect to correct answers), whereas only 4.0% of the student population changed their responses in a negative way (from correct to incorrect answers, P < 0.001; Fig. 3). Taken together, the magnitude of the peer instruction positive effect was 5.6 times higher than the magnitude of the peer instruction negative effect. Therefore, the beneficial effects of peer instruction on students' performance were observed in the group of students having individual incorrect answers ("weaker students") (Fig. 3). These results are in agreement with reports by Crouch and Mazur (7). These authors reported that it is much easier to change the mind of someone who is wrong than it is to change the mind of someone who has selected the correct answer for the right reasons (13). Thus, there is always an increase and never a decrease in the number of correct answers (solutions) after discussion with classmates.
Faculty members are often reluctant to incorporate active learning activities in class. The reasons most often advanced for not including these active learning activities include not being able to cover as much content and the excessive preparation time required for devising strategies promoting active learning (1). However, as stated by Mazur (13), using time for peer instruction greatly improves the student's level of understanding with relatively little effort and no capital investment. In addition, the instructor has several important roles during the process. For example, the instructor must model appropriate social skills, including listening and providing constructive feedback or eliciting more indepth responses through probing questions. The instructor must also reinforce these positive behaviors by publicly commenting on the ways students use them effectively (5).
Student perceptions regarding the peer instruction activities are in agreement with previous work (5, 6, 16, 17). Students appreciated the interactions with peers and with the instructor. This interaction provided immediate feedback, which is not possible during the traditional lecture format. The students reported that peer instruction facilitated their learning of the topics. In this content, students were seen to be enthusiastically engaged in content-based discussions, giving support to their choices. Finally, students enjoyed this learning experience and recommended it for other courses.
In conclusion, pausing four to six times during a 90-min class to allow peer instruction of qualitative problems enhanced the students' performance on qualitative problem-solving questions.
Appendix A: Samples of Assessed Cardiovascular Questions
1. Predict (increase/decrease/no change) what would happen to the velocity of blood flow through systemic vessels if you provide a medication causing smooth muscle contraction:
Increase (correct)
Decrease
No change
2. Predict (increase/decrease/no change) what would happen to the resting membrane potential in cardiac muscle cells if the extracellular K+ concentration increases:
Increase
Decrease (correct)
No change
3. Predict (increase/decrease/no change) what would happen to cardiac output if you provide a medication causing smooth muscle relaxation:
Increase
Decrease (correct)
No change
4. Predict (increase/decrease/no change) what would happen to stroke volume, end-diastolic volume, and cardiac output if afterload increased:
5. Predict (increase/decrease/no change) what would happen to the volume of blood returning to the heart through the veins if right atrial pressure (central venous pressure) increased:
Increase
Decrease (correct)
No change
6. Predict (increase/decrease/no change) what would happen to tissue fluid formation if you provide a medication causing smooth muscle contraction in veins:
Increase (correct)
Decrease
No change
Appendix B: Samples of Assessed Respiratory Questions
1. Predict (higher/lower/the same) how the tidal volume of a horse immediately after a race would compare with its tidal volume at rest:
Higher (correct)
Lower
The same
2. Predict (increase/decrease/no change) what will be the effect on alveolar ventilation of breathing at higher frequency while keeping the same respiratory volume:
Increase
Decrease (correct)
No change
3. Predict (increase/decrease/no change) what would happen to functional residual capacity in a lung disease leading to emphysema:
Increase (correct)
Decrease
No change
4. Predict (increase/decrease/no change) what would happen to airflow resistance if you provide a medication causing smooth muscle relaxation:
Increase
Decrease (correct)
No change
5. Predict (increase/decrease/no change) what would happen to arterial PO2 in a dog breathing 100% oxygen (oxygen therapy):
Increase (correct)
Decrease
No change
6. Predict (increase/decrease/no change) what would happen to ventilation and perfusion in a dog having its right pulmonary artery blocked:
Appendix C: Samples of Assessed Renal Questions
1. Predict (increase/decrease/no change) what would happen to the glomerular filtration rate, renal blood flow, and glomerular capillary pressure during efferent arteriolar vasoconstriction:
2. Predict (higher/lower/the same) how urine osmolarity would be compared with plasma osmolarity if you provide a medication blocking the 2Cl–-Na+-K+ cotransporter (i.e., furosemide):
Higher (correct)
Lower
The same
3. Predict (higher than 1/lower than 1/equal to 1) the fractional excretion of a drug that is both filtered and secreted (with no reabsorption).
Higher than 1 (correct)
Lower than 1
Equal to 1
4. Predict (increase/decrease/no change) what would happen to the urine concentration capacity in a dog given a low-protein diet:
Increase
Decrease (correct)
No change
5. Predict (increase/decrease/no change) what would happen to plasma Na+ concentration, total body Na+ content, plasma K+ concentration, and total body K+ content if you provide a medication with an aldosterone antagonistic effect:
6. Predict (increase/decrease/no change) what would happen to urine elimination of tritratable acids if the organic load of metabolic acids increases:
Increase (correct)
Decrease
No change
7. Predict (increase/decrease/no change) what would happen to both the volume and osmolarity of extra- and intracellular fluid compartments if you provide a hypertonic saline solution (i.e., 7.5% NaCl) intravenously:
GRANTS
This work was supported, in part, by The American Physiological Society Teaching Career Enhancement Award (to M. J. Giuliodori).
REFERENCES
Bonwell C and Eison J. Active Learning: Creating Excitement in the Classroom. Washington, DC: George Washington Univ. Press, 1991.
Byrnes JP. Cognitive Development and Learning in Instructional Contexts. Boston, MA: Allyn and Bacon, 1996.
Chi M, de Leeuw N, Chiu M, and La Vancher C. Eliciting self-explanations improves understanding. Cogn Sci 18: 439–477, 1994.
Committee on Developments in the Science of Learning, Committee on Learning Research and Educational Practice, and National Research Council. How People Learn: Brain, Mind, Experience and School. Washington, DC: National Academy Press, 2000.
Cortright RN, Collins HL, and DiCarlo SE. Peer instruction enhanced meaningful learning: ability to solve novel problems. Adv Physiol Educ 29: 107–111, 2005.
Cortright RN, Collins HL, Rodenbaugh DW, and DiCarlo SE. Student retention of course content is improved by collaborative-group testing. Adv Physiol Educ 27: 102–108, 2003.
Crouch C and Mazur E. Peer instruction: ten years of experience and results. Am J Physics 69: 970–977, 2001.
DiCarlo SE. Cell biology should be taught as science is practised. Nat Rev Mol Cell Biol 7: 290–296, 2006.
Johnson D, Johnson R, and Smith KA. Active Learning: Cooperation in the College Classroom. Edina, MN: Interaction Book, 1991.
Lujan HL and DiCarlo SE. First-year medical students prefer multiple learning styles. Adv Physiol Educ 30: 13–16, 2006.
Lymna F. The responsive classroom discussion. In: Mainstreaming Digest, edited by Anderson AS. College Park, MD: Univ. of Maryland College of Education, 1981.
Mazur E. Peer Instruction: a User's Manual. Upper Saddle River, NJ: Prentice Hall, 1997.
Mazur E. Peer instruction: getting students to think in class. Proc ICUPE 399: 981–988, 1997.
Michael J and Modell H. Active Learning in Secondary and College Classrooms: a Working Model for Helping the Learner to Learn. Manwah, NJ: Erlbaum, 2003.
Michael J and Rovick A. Problem Solving in Physiology. Upper Saddle River, NJ: Prentice Hall, 1999.
Rao SP, Collins HL, and DiCarlo SE. Collaborative testing enhances student learning. Adv Physiol Educ 26: 37–41, 2002.
Rao SP and DiCarlo SE. Peer instruction improves performance on quizzes. Adv Physiol Educ 24: 51–55, 2000.
Rao SP and DiCarlo SE. Active learning of respiratory physiology improves performance on respiratory physiology examinations. Adv Physiol Educ 25: 55–61, 2001.
Rowe M. Pausing principles and their effects on reasoning in sciences. In: Teaching the Sciences: New Directions for Community Colleges, edited by Brawer F. San Francisco, CA: Jossey-Bass, 1980.
Thorndike EL and Woodworth RS. The influence of improvement in one mental function upon the efficiency of other functions. Psychol Rev 8: 247–261, 1901.(Mauricio J. Giuliodori1, Heidi L. Lujan2)