A comparative study of how high school students understand stem cells

A comparative study of how high school students

understand stem cells

By Jonathan Moyer, MST candidate

Committee

Dr. John R. Thompson (advisor) Dr. Mary S. Tyler

Outline

• Introduction

• Unit Design

• Research Design

• Results and Analysis

Introduction

MST Research Internship Program at the Jackson Laboratory

• Conduct biology research

• Develop a unit of study based on research

• Implement in high schools

Why study stem cells?

• Ideal context for cell division, cell differentiation, and development (US Content Standard C)

• Potential health, biotechnology applications reinforce cell as basic component of life

• Highly controversial topic:

ÎHighlights ethical and social aspects of science

(US Content Standard F, Maine Science and Technology Standard L8)

Unit Design

Backwards design method by Wiggins and McTighe (2005)

1. Identify desired learning outcomes (“enduring understandings”), develop essential questions

2. Determine acceptable evidence (assessments)

Unit Design

1. Identify desired learning outcomes (“enduring understandings”)

a) Possess enduring value beyond the classroom b) Reside at the heart of the discipline

c) Require discovery of abstract or complicated concepts d) Offer potential for engaging students

• “Stem cells are cells that can become other cells. Depending on their potency, they can become any cell required for life or cells of a limited type.”

• “Stem cells are found from two main sources: the bodies of adults and the early stages of embryo development. Embryonic stem cells are thought to possess greater potency than adult stem cells.”

• “Researchers hope that the ability of stem cells to become other cells can be harnessed to treat a variety of medical conditions.”

Unit Design

1 (cont’d). Develop essential questions:

• What are stem cells?

• How are stem cells obtained?

• Why are stem cells so potentially useful?

ÎPrimarily fact-based, “lower order” questions

ÎVery broad, elicit a variety of student responses, can “hook” students

Unit Design

2. Determine acceptable evidence (assessments)

Students should be able to:

• Explain • Interpret • Apply • Show perspective • Empathize • Self-knowledge Continuum of assessments:

Informal checks for understanding Observations and dialog

Quizzes/Tests

Academic Prompts Performance Tasks

Unit Design

2 (cont’d). Determine acceptable evidence (assessments)

• Research essay: one to two page paper answering unit essential questions

• Policy exploration: select or propose a governmental policy toward stem cell research and explore ramifications

Unit Design

Determine the following:

• Knowledge and skills students need to perform effectively

• Activities that equip students with the necessary knowledge and skills • How students will best learn the knowledge and skills

• Resources required to reach those goals • A coherent and effective unit design

Inquiry-based Unit Outline

Period 1: Class discussion on initial ideas about stem cells

Period 2: Working in pairs, research answers to the unit questions (use books, articles, Internet, etc.)

Period 3: Class discussion of research results

Period 4: Working in small groups, develop policy towards stem cell research.

Lecture-based Unit Outline

Period 1: Early stages of development (fertilization, cleavage stages, blastocyst, gastrulation)

Period 2: Stem cells

Period 3: Current and proposed applications

Period 4: Controversial aspects of stem cell research

Research Design

Research Questions

1. What are initial student ideas of stem cells and stem cell research?

2. How does the inquiry-based teaching method compare to traditional lecture-based instruction?

3. Does exposure to the material change student opinions?

Research Instruments

• Pre-/Post-tests

Research Design

Student population:

2005:

Central High School (CHS05), East Corinth • 6 sophomores from Academic Biology

John Bapst High School (JBHS05), Bangor • 39 juniors and seniors from AP Biology

2006:

John Bapst High School (JBHS06)

• two groups of 15 from AP Biology, one did inquiry and the other did lecture

Pre-/Post-tests

Pre-tests: 2005

Q1: “What are stem cells?”

Q2: “Where do stem cells come from?”

Q3: “Why are scientists interested in stem cells?” 2006

Q4: “Why is stem cell research controversial?”

Q5: “What makes stem cells different from other cells? Circle all that apply.

a) Stem cells contain all of an organism’s DNA.

b) Stem cells contain information about an individual’s genetic tendencies.

c) Stem cells have the potential to become other cells. d) Stem cells are used up as the organism grows older. e) Stem cells are immature, undeveloped cells.

Pre-/Post-tests

Post-tests: Same as JBHS05 pre-tests, but with:

JBHS05

Q4: “You feel you learned a lot about stem cells.”

Q5: “You have changed the way you think about stem cells.”

Indicate agreement on five-point Likert scale from “1” (“Strongly Agree”) to “5” (“Strongly Disagree).

Pre-/Post-tests

JBHS06

Q6: Has this unit changed the way you think about stem cells? If so, please explain how.

Q7: “I feel I learned a lot about stem cells.”

Interviews

• One-on-one, standardized, open-ended, pre-instruction interviews

• Discuss pre-test questions

• Additional questions:

-What makes stem cells different from other cells?

-When and where did you first hear about stem cells?

Results and Analysis

Q1: What are stem cells?

• Most students indicated that stem cells become other cells.

“Stem cells are cells that can regenerate into other cells. Embryonic stem cells can generate into any type of cell.” (JBHS05)

“They’re cells in the bone marrow that evolve into any other type of cell.” (JBHS05)

“Stem cells are cell that have not yet developed so that they perform a specific function.” (JBHS05)

Results and Analysis

• Stem cells have more DNA than other cells

“Stem cells are cells that can develop into any kind of cell … they contain all of an organism’s DNA so they can develop into any kind of cell.” (JBHS05)

Results and Analysis

• Most students cited fetuses, embryos, umbilical cord blood as primary source

• Certain parts of the body, such as bone marrow, the spine, or nerve cells

• Many students suggested pregnancies are aborted to obtain stem cells

Results and Analysis

Q3: Why are scientists interested in stem cells?

• Most students talked about medical applications

• Treating conditions with a neurological component (paralysis, Alzheimer’s, etc.)

• Regrow organs

Results and Analysis

• Most students said because it involves abortion or killing an unborn child

• General social, personal, or health concerns

“It is controversial because it is not a normal/natural way to repair the body.”

Results and Analysis

Interviews: Six interviews done in JBHS06

• Interview 1: Student believed stem cells were found only in the embryo.

• Interview 4: Student knew virtually nothing about stem cells or stem cell research but was very much in favor of embryonic stem cell

Results and Analysis

• Stem cells in controversial because it harms the fetus

and: “It’s just kind of impersonal, and some people might view it as inhumane, you know, if you’re using it for its cells rather than its person.”

• Stem cells used up, but struggles to reconcile this belief with adults having stem cells: Stem cells used up “after babies [are] done getting all of [their] more mature characteristics. But I thought adults had

them too, so that doesn’t make sense.”

• Stem cells have less DNA than other stem cells “because they’re immature, maybe.”

Results and Analysis

• Stem cells are used up by the “age of 21 because puberty’s over and your body kinda stays in a certain shape.”

• Stem cells “adapt” to environment: “I would say [cell differentiation] is a lot like adaptation because the cells are able to adapt to other cells’ lifestyles, like humans were able to adapt to their environment…”

• Stem cells acquire DNA from cells they try to emulate or adapt to: “[Stem cells] would copy themselves off of a template of another cell and if that cell had the DNA the stem cells would get the DNA from the copy of the template.”

Results and Analysis

• Confusion over the zygote: “I don’t know if you really could

call [the zygote] a stem cell or not. It doesn’t seem like there’s that much more to work with.”

Interview 6:

• Stem cells have more DNA than other cells. The DNA is “split-up” amongst other cells.

Results and Analysis

JBHS05:

Q4 Average: 1.8

Students “Agree” that they learned a lot about stem cells.

Q5 Average: 2.7

Students had no strong opinion as to whether or not instruction changed their beliefs about stem cell research.

JBHS06:

Q6: Most students indicated that instruction didn’t changed the way they think about stem cell research.

Results and Analysis

Q5: What makes stem cells different from other cells?

a) Stem cells contain all of an organism’s DNA.

b) Stem cells contain information about an individual’s genetic tendencies.

c) Stem cells have the potential to become other cells. d) Stem cells are used up as the organism grows older. e) Stem cells are immature, undeveloped cells.

JBHS06 Inquiry Q5 0 2 4 6 8 10 12 14 16 a b c d e Response Pre-test Post-test JBHS06 Lecture Q5 0 2 4 6 8 10 12 14 16 a b c d e Response Pre-test Post-test

Results and Analysis

CHS05 pre-/post-test grades by question (N=6)

Question Pre-test Average Post-test Average Gain (%)

Q1 1.167 3.167 71 Q2 1.000 3.167 72 Q3 1.333 3.000 62 JBHS05 pre-/post-test grades by question (N=39)

Question Pre-test Post-test Average Gain (%)

Q1 1.700 3.205 65 Q2 1.500 3.256 70 Q3 1.725 3.641 40

JBHS06 inquiry pre-/post-test grades by question (N=15)

Question Pre-test Average Post-test Average Gain (%)

Q1 1.733 2.6 62

Q2 1.933 3.133 58 Q3 1.800 3.133 61 Q4 1.667 2.867 51 JBHS06 lecture pre-/post-test grades by question (N=15)

Question Pre-test Average Post-test Average Gain (%)

Q1 1.867 2.267 19

Q2 1.933 2.800 42

Q3 1.667 3.067 60

Q4 2.133 3.333 64

Comparison of Inquiry and Lecture:

• Two-tailed, matched-pair analysis between JBHS06 inquiry and lecture

• Null Hypothesis: No difference between post-test means

• Alternative Hypothesis: There is a difference between post-test means

Results and Analysis

Two-tailed, Matched Pair Analysis Question tobs

Q1 1.685 Q2 1.685 Q3 0.269 Q4 -2.432

For df = 14, α = 0.05 (97.5% confidence interval), t = 2.145 • Only Q4 is significant

Conclusions

Pre-tests, interviews show a variety of initial student ideas on stem cells:

-Abortions are performed to get stem cells

-Stem cells have different amounts of DNA than other cells

ÎMay be related to “cells DNA specific to their function” -Stem cells are “used up” when you grow older

Conclusions

• Learning gains for lecture and inquiry

• Q4 only statistically significant result between lecture and inquiry

ÎInquiry needs more time

ÎStudents “primed” or “trained” for lectures

ÎQuestions are mostly fact-based 3. Exposure to Material

Post-test results indicate that students feel exposure to the topic didn’t change their opinion on the topic.