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Understanding the Nature of Science Through College Introductory
Biology
Bridget Tuberty <[email protected]>P.M. Dass <[email protected]>
Appalachian State UniversityBoone, NC USA
Presentation at the 9th IHPST Conference, June 2007
University of Calgary
Calgary, AB Canada
When asked about the Theory of Evolution former President Reagan replied,
“Well, it’s a theory a scientific theory only…”
Why does understanding the Nature of Science matter?
…25 years later
• According to the current President Bush,
"Both sides ought to be properly taught . . . so people can understand what the debate
is about,"
Primary Goal of Science Education
Both the American Association for the Advancement of Science (AAAS) and the National Research Council (NRC) agree that it should be
Scientific Literacy
What is Scientific Literacy?
“…the scientifically literate person is one who is aware that science, mathematics, and technology are interdependent human enterprises with strengths and limitations; understands key concepts and principles of science; is familiar with the natural world and recognizes both its diversity and unity;
and uses scientific knowledge and scientific ways of thinking for individual and social purposes.”
AAAS, 1990, pg ix
Traditional Views of NOS
• Scientific claims are objective because the theories and laws used to make such claims are based on empirical observation
• The testing of hypotheses is controlled by a logical established scientific method
• Science progresses linearly with the ultimate goal of finding a comprehensive theory
Contemporary view: The assumptions and values of NOS
we want students to learn
1. Science demands and relies on empirical evidence
2. In spite of commonalities there is no single step-by-step scientific method
3. Scientific knowledge is tentative yet durable
4. Laws and theories are related but distinct kinds of scientific knowledge
5. Science is a highly creative endeavor
Contemporary NOS cont.
6. Science has a subjective element
7. Science is a complex social activity
8. Science and technology impact each other, but they are not the same
9. Science cannot provide complete answers to all questions
McComas, 2004
Research Questions
1. What conceptions of the NOS do college students bring to the BIO-1101 course?
2. To what extent does the BIO-1101 for non-majors course influence students’ conceptions of the NOS?
Methods: Participants• Fall 2005, BIO-1101
non-majors course
81 Freshman
163 Sophomores
45 Juniors
6 Seniors
Instructor Section EnrolledTotalM/F
ParticipatedTotalM/F
A 1 7737/40
3515/20
B 2 8634/52
419/32
C 3 9055/35
7428/46
4 8835/53
D 5 11658/58
8515/70
6 13051/79
E 7 12755/72
6018/42
Total 714325/389
29585/210
Quantitative Methods: Views on Science-Technology-Society (VOSTS)
Questionnaire
• Developed empirically by Aikenhead and Ryan (1992)
• Validity has been proven in that it reflects students viewpoints
• Researcher can select which questions to use ~ 25 out of the 118
• VOSTS has been successfully used with both high school and university students and with teachers
• Response choices can be categorized allowing for hypothesis testing with inferential statistics
Categorization of VOSTS Responses
• Desirable (D): The choice expresses a contemporary view
• Acceptable (A): The choice expresses a view that includes a number of legitimate points
• Undesirable (U): The choice expresses a view that is inappropriate or not legitimate (doesn’t match any aspect of the contemporary view)
(Dass 2005; Rubba et al. 1996)
Sign test analysis• Response categories given numerical values: D
= 3, A = 2, U = 1• Conversion to ordinal data allows for the non-
parametric Sign test to analyze change from pre to post test
• Ho-the median difference in VOSTS item response categories from pre-test to post-test will not differ from 0 was tested against the alternate hypothesis
• Ha-the median difference in VOSTS item response categories from pre-test to post-test will differ from 0
Qualitative Methods: Individual Interviews to Corroborate VOSTS
Responses
• Selection of 11 VOSTS items• All Instructors• Students purposefully selected
based on quantitative findings: 26 students
• Approx. 30 minutes each• Paid for Transcription
Qualitative Methods: Classroom observations
• Each Instructor’s class was video-recorded during:
1. Mendelian genetics
2. DNA structure
3. Microevolution
Resulted in 21 hours and 31 minutes of lecture video which in turn resulted in approximately 200 hours of transcription
Quantitative Results: College Students Conceptions of NOS on Pre Course Survey
Question U A D
1 6.3 59.1 34.613 15.2 25.0 59.814 19.9 36.5 43.515 23.8 16.1 60.116 13.3 54.1 32.717 81.5 12.4 6.018 8.3 90.7 1.019 9.7 34.3 56.020 15.5 57.6 26.921 17.4 43.8 38.822 9.5 90.5 0.023 49.3 0.0 50.724 45.7 12.0 42.325 51.9 37.0 11.1
2 5.0 24.3 70.43 20.3 10.3 69.34 5.4 73.5 21.1
5 30.6 23.6 45.86 3.7 66.0 30.37 2.3 12.6 85.08 31.1 9.8 59.19 42.5 31.1 26.4
10 17.8 58.7 23.511 17.7 40.3 42.012 14.7 40.7 44.7
Nature ofScientificKnowledge
Characteristics ofScientists
SocialConstruction ofScientificKnowledge
NOS Component
Quantitative Results: To What Extent does BIO 1101 Influence Student Conceptions of NOS
Question 16: Even when scientific investigations are done correctly, the knowledge that scientists discover from those investigations may change in the future.
Incorporates:
(3) Scientific knowledge is tentative but durable
Even when scientific investigations are done correctly, the knowledge that scientists discover from those investigations may
change in the future.
Desirable Conception Choice:
B. Because the old knowledge is reinterpreted in light of new discoveries. Scientific facts can change.
Instructor Negative (-) differences
Positive (+) differences
Ties p
A 11 7 17 0.481 B 13 9 21 0.523 C 19 12 39 0.281 D 24 17 43 0.349 E 18 14 30 0.596
Total 85 59 150 0.037
*No instructor Desirable
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Student comments on the tentative nature of scientific knowledge
• “Yes, we talked a lot about how things were always changing and how even though multiple experiments could prove a certain theory-just one could disprove it.” from Instructor C’s class
• “…knowledge is always changing, the world is flat the world is round. In Instructor C’s class, he/she was always like; scientists are always out to disprove each other, because that’s how science gets better.”
Question 17: Scientific ideas develop from hypotheses to theories, and finally, if they are good enough, to being scientific laws. Your position basically:
Incorporates:
(4) Laws and theories are related but distinct kinds of scientific knowledge
Scientific ideas develop from hypotheses to theories, and finally, if they are good enough, to being scientific laws.
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Desirable Conception Choices:E. Theories can’t become laws because they both are different types of ideas. Laws
describe things in general. Theories explain these laws. However, with supporting evidence, hypotheses can become theories (explanations) or laws (descriptions).
Instructor Negative (-) differences
Positive (+) differences
Ties p
A 1 2 32 1.000 B 10 7 26 0.629 C 12 8 52 0.503 D 9 9 68 1.000 E 10 7 45 0.629
Total 42 33 223 0.356
*Instructor D only Desirable
Instructor B discussing Mendelian genetics during lecture
• “So the 1st law or the 1st theory that Mendel came up with he called the Law of Segregation …so now through his experiments so far we’ve done a monohybrid cross and a test cross both to support his Theory of Segregation.”
• “So from the data he collected he formed a theory, Theory of Segregation, now people call it the Law of Segregation of alleles…”
Student Interviews About Hypotheses, Theories, and Laws (oh, my)
• “I’m going to lean more to how many times its been proven. If it’s been proven so many times and hasn’t been able to be disproven then, I mean, it becomes a law.”
• “I don’t think that it should, uhm, because like a theory you know isn’t 100% true and I don’t know, I don’t know, everything that we’re taught in science is a theory and they’ve been teaching it for so long and it just seems like that if that were true it would have already become a law.”
• “…I think like, with hypotheses they have to be tested a lot, like experimented and experimented and have all of the supporting evidence gathered together in order to make it a theory so after its been proven true for so many times then I think yes it’s a hierarchy but once it’s proven by experiments it’s a theory and then once that theory becomes absolutely true then it’s a law.”
Instructor A’s student
Instructor B’s student
Instructor E’s student
Discussion of Theory in Instructor C’s Lecture on Microevolution
• “Remember how we spoke about theories aren’t hypotheses, they’re basically these unifying principles that are supported by everything that we know about the field of biology and so that’s why biologists get really irate when people want to not allow it to be taught because it’s basically the fiber that holds everything that we know about biology together and so that’s why it’s really important and actually why I’m teaching it right at the very end of the semester is because we will be able to see that everything that we learned this semester goes into supporting this theory.”
• “Well, you always hear that the Theory of Evolution is just a theory, but when scientists think of the word theory it’s as if theory means law to the scientist and theory is hypothesis to the lay person. Like, oh it’s just a theory, like it’s just something like a hypothesis, but scientific theory is much more concrete with strong evidence and it’s just a theory, laws are supposed to be 100% concrete stable…theories you can change around, I don’t know, I’m not really sure anymore.”
Student Interviews About Hypotheses, Theories, and Laws (oh, my)
Instructor C’s student
When scientists investigate, it is said that they follow the scientific method. The scientific method is: Your position, basically: (Please read from A to M, and then choose one.) U/1 A. the lab procedures or techniques; often written in a book or journal, and usually by a scientist. A/2 B. recording your results carefully. A/2 C. controlling experimental variables carefully, leaving no room for interpretation. A/2 D. getting facts, theories or hypotheses efficiently. A/2 E. testing and retesting – proving something true or false in a valid way. A/2 F. postulating a theory then creating an experiment to prove it. A/2 G. questioning, hypothesizing, collecting data and concluding. A/2 H. a logical and widely accepted approach to problem solving. A/2 I. an attitude that guides scientists in their work. D/3 J. Considering what scientists actually do, there is really no such thing as the scientific method. U/1 K. I don’t understand. U/1 L. I don’t know enough about this subject to make a choice. U/1 M. None of these choices fits my basic viewpoint.
Question 18: Explicitly addresses: (2) in spite of commonalities there is no single step-by-step scientific
method
Instructor Negative (-) differences
Positive (+) differences
Ties p
A 3 1 31 0.625 B 7 3 33 0.344 C 18 4 52 0.004 D 10 5 71 0.302 E 5 8 50 0.581
Total 43 21 237 0.009 *All Instructors Acceptable except D Undesirable
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Portrayals of the Scientific Method from Mendelian Genetics Lectures
• Instructor C: “…remember when we spoke about the scientific method the 1st day of class? So, uhm, you remember how we said you make an observation, form a hypothesis, do an experiment that gets results, which means you ask more questions, make more hypotheses and it just kind of becomes this expansion of knowledge type of thing…”
• Instructor E: “Good, okay, nice hypothesis, nice explanation, you’ve got to test it, it’s got to be tested, you’ve got to use the hypothesis to set up another experiment, predicting the results from this, you know using, using this hypothesis.”
The scientific method as a series of steps perpetuates the view that theories are easy to
dismiss
• Dagher and BouJaoude, (2005) found that students felt the theory of evolution did not follow the scientific method therefore it was lacking evidence to make it credible
• Sandoval and Morrison (2002) concluded that the simplistic linear model of the scientific method promotes the idea of theories as proven hypotheses
• Compound this with the hierarchy of scientific ideas, or the belief that theories are not as “proven” or valid as a law and it is easy to see how misconceptions about science affect people and their reasoning on the theory of evolution
How this could be perpetuated by the language used in lecture
• “…I’d also like to give lots of examples of how we see this today because being scientists, without evidences, without experimental proof this is all still trajectory, okay.”
• “Now when you look at something and make an observation and then attempt to come up with a conclusion we call this pattern versus process. We see a pattern we try to make a conclusion about it, however we didn’t do any sort of experiment to get our conclusion, okay, this is not science that is simply making an observation. Mendel had enough scientific background to know that he needs to set up an experiment in a logical manner and attack this question with data not just with observations.”
Instructor B
What students said when asked where they had gotten their views on scientific ideas and
the scientific method
• “I mean going all the way back to middle school and high school. A scientific law is much more above a theory.” A
• “…it’s the way my teachers have always taught it since, you know I actually started paying attention in science classes like 9th grade you know, you see, you test your hypotheses and that becomes a theory that you can base other things off of and then we learned about laws which are proven and unquestionable.” D
• “Uhm, when you’re in the 7th grade and you learn the scientific method that is exactly what you learn and you experiment and you go through those 4 well its really 7 steps.” A
• “It has been pounded into my mind since the start of scientific education…steps, concrete one after another.” C
Explicit discussions can influence students
Students that selected J on post course survey,
Bridget: “Has there been anything in particular that influenced you to say that?”
Student: “I think I remember a professor having a little spiel about there being no actual scientific method.”
Bridget: “Was that in 1101?”Student: “Possibly, yes it was in college. I think that the
scientific method as its presented in textbooks can be an idea of what science tries to do, the ideals, I think in an actual experiment you don’t have to the steps, you don’t follow the steps…in high school you had this whole little outline you know you start, you question things, you make hypotheses, and you develop an experiment and you experiment and if it supports your hypothesis then your hypothesis becomes your theory, if it doesn’t support then you alter the hypothesis and you go through the steps all over again.” D
• 40% of students selected the step-by-step method on post-test compared to 44% on pre-test
• However more students selected ‘U’ choice A (lab procedures and techniques written in a lab book or journal usually by a scientist)
Response choice Frequency Percent a 34 11.3 b 11 3.7 c 22 7.3 d 16 5.3 e 31 10.3 f 6 2.0 g 121 40.2 h 44 14.6 i 4 1.3 j 1 .3 k 2 .7 l 2 .7 m 7 2.3 Total 301 100.0
Response choice Frequency Percent a 19 6.3 b 12 4.0 c 12 4.0 d 17 5.6 e 32 10.6 f 8 2.7 g 132 43.9 h 57 18.9 i 3 1.0 j 3 1.0 l 3 1.0 m 3 1.0 Total 301 100.0
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p=0.009
Conclusions• Students still hold misconceptions of NOS
• The 1101 course is currently taught as a historical introductory course and in most cases is not significantly influencing students toward contemporary conceptions of NOS
• Abd-El-Khalick & Lederman (2000); Schwartz & Lederman (2002) found that reiterations of history not enough to influence students and that explicit discussion about NOS is needed
Why improving student conceptions of NOS matters
• Student views about science determines how they learn science (Edmondson & Novak, 1993; Songer & Linn, 1991)
– When students believe that scientists simply add facts to a body of knowledge as opposed to deliberating between different viewpoints they are more likely to memorize facts as a way of learning and are therefore less likely to integrate science with their own viewpoints
NOS misconceptions can affect students’ abilities to deal with scientific
controversies
• People who do not incorporate scientific knowledge with personal knowledge lack reflective reasoning skills and are not able to deliberate between different viewpoints and evidence resulting in their being more likely to accept the views of authoritative figures without really developing and understanding of those views (Lawson & Weser, 1990)
The good news
• Students who take college level science course are more scientifically literate and more comfortable with science (Miller, 2004)
• Although certain conceptions are more ingrained than others we can still influence college students’ conceptions (Edmondson & Novak, 1993; Lord & Marino, 1993)
Implications
• More emphasis of NOS and science content for science education programs (Brickhouse et. al., 2000; Swartz & Lederman, 2002)
• If the general education goal is to improve scientific literacy then curriculum reform towards a more outcome assessment based program away from a content driven course is a good idea
Questions?
