Activity 2: The
Pellagra Story
White space
How do you think
doctors determine the
cause of a disease?
Challenge:
What are the common methods of scientific
problem solving?
Introduction: Video and notes on video
Evidence, observation, inference, tradeoff,
ethics
Vocabulary:
Materials: √
Procedure: √
Data:
1 Student Sheet 2.2,
1 Student Sheet 2.3,
Analysis:
AQ 1, AQ 2b, 4, 5, 6
1
Imagine that doctors are observing a new disease, and they don’t know what
causes it.
What are some possible causes of diseases?
What kinds of things would scientists do to learn more about a disease and its
cause or causes?
Read the Analysis questions
Watch the Video clip on pellagra one time, just listening carefully.
Watch the Video clip on pellagra again, taking notes on handout student sheet 2.1
http://www.sepuplhs.org/movies/odys08_vid_pellagra_350.mov
odys08_vid_pellagra_350.mov
2
Analysis Questions
1. a. What was the first step in Dr. Goldberger’s research into pellagra? Explain why
this step was important in developing his hypothesis.
b. During this first step in his research, what evidence did Dr. Goldberger
find that suggested that pellagra was not caused by germs?
2. b. What did he do to provide evidence of the relationship
between pellagra and nutrition? Be sure to explain how his research provided
evidence that supported or disproved his hypothesis.
Analysis Questions
4. Compare the steps of the traditional scientific method to the steps Dr. Goldberger followed
to investigate pellagra. How were the steps the same? How were the steps different?
5. Fill in the “After” column for statements 3 and 4 only on Sheet 1.1, “Anticipation Guide:
Ideas about Experimental Design.”
Did your thinking change?
6. To investigate his hypothesis, Dr. Goldberger had prisoners volunteer to be fed a poor diet; as
a result, 7 out of 11 prisoners developed pellagra.
What do you think about Dr. Goldberger’s decision to experiment on people?
Support your answer with evidence and identify the trade-offs of your decision. Hint: To write
a complete answer, first state your opinion. Provide two or more pieces of evidence that
support your opinion. Then consider all sides of the issue and identify the trade-offs of your
decision.
What was the problem of pellagra?
In 1914, pellagra was a common disease in the United States. It caused rashes, insanity and
death.
What did people think caused pellagra?
1. Eating corn
2. An insect
3. Bacteria/germs
4. Lack of nutrition/poor diet
What evidence did Dr. Goldberger observe or collect about pellagra?
Pellagra was common in the South, particularly in poor areas and institutions (such as mental
hospitals, orphanages, and prisons).
Many people in the South ate a poor diet, consisting of cornbread, fatback (pork), and syrup.
Staff at institutions (such as mental hospitals, orphanages, and prisons) did not have pellagra.
Orphans provided with fresh vegetables, meat, and milk either recovered from pellagra or did
not get it.
Some prisoners fed a poor diet developed pellagra. When provided a better diet, they
recovered.
What did Dr. Goldberger conclude about the cause of pellagra?
Dr. Goldberger concluded that pellagra was caused by a nutritional deficiency (poor diet).
Take out your Vocabulary Log
Observation: Any description or measurement gathered by the
senses
Inference: A conclusion, or the process of developing a conclusion
based on evidence.
3
In the video clip, one of the presenters comments that the fact that
orphans provided with fresh vegetables, meat, and milk either
recovered from pellagra or did not get it “was not scientific
evidence.”
Why do you think the presenter made this comment?
Do you agree with the presenter? Why or why not?
Key to Student Sheet 2.2, “Observations and Inferences”
Identify each of the following statements as either an observation or an inference that was
made about pellagra.
Observation Inference
___
X*
Corn causes pellagra.
X
___
Only children in the orphanage developed pellagra. The staff did not.
X
___
Changing the orphans’ diet cured those who had pellagra.
X
___
Only people who lived in the South got pellagra.
___
X
X
___
Pellagra is not an infectious disease.
Pellagra causes skin rashes and, eventually, insanity.
___
X*
People get pellagra because they are poor.
___
X
Pellagra is caused by diet.
X
___
___
X*
Orphans and prisoners who ate a balanced diet did not develop pellagra.
The Southern way of life caused pellagra.
1. Look at the statements that you marked as inferences. Based on the evidence that Dr. Goldberger
found, put a star next to each inference that is faulty.
2. Choose one of the inferences that you put a star next to, and explain how that inference could have
been made based on observations.
The Pellagra Story:
Dr. Goldberger and the Traditional Scientific Method
Steps of the traditional scientific method
Same or different?
Steps taken by Dr. Goldberger
State the Problem or Question
Same
Dr. Goldberger was presented with the problem "What causes
Pellagra?" when asked to investigate.
Propose an explanation (hypothesis)
Same
Dr. Goldberger hypothesized that an inadequate diet caused
pellagra.
Collect Evidence
(experiment)
Same
Dr. Goldberger fed orphans a balanced diet and observed it's
effect on Pellagra
Analyze data
Same
Dr. Goldberger recorded and analyzed data about orphans
Draw conclusions, and if necessary,
revise and repeat
Different
Dr. Goldberger did not draw a final conclusion after his
investigation with the orphans. He obtained more evidence
by conduction an experiment with prisoners.
Analysis Question 1a
1. a. What was the first step in Dr. Goldberger’s research into pellagra? Explain why this step
was important in developing his hypothesis.
The first thing that Dr. Goldberger did was to visit sites where pellagra was prevalent.
He focused on the southern United States and visited institutions such as orphanages and prisons.
He conducted this background investigation before forming any hypothesis for the cause of pellagra.
This was an important step in developing his ideas. It was during this initial period that Dr.
Goldberger observed common factors (such as poverty and diet) linked to pellagra and therefore
hypothesized that pellagra may be a nutritional deficiency (poor diet).
These are often overlooked elements of scientific study and are usually essential to the development of
strong hypotheses.
Analysis Question 1b
During this first step in his research, what evidence did Dr.
Goldberger find that suggested that pellagra was not
caused by germs?
Dr. Goldberger’s observations about the prevalence of pellagra
among poor and institutionalized people provided some evidence
that pellagra did not occur randomly.
He pointed out that staff at institutions where pellagra was common
did not have it, while many of the patients did. This provided some
evidence that pellagra was not an infectious disease, since victims
did not transmit it to the staff.
Scoring Guide
LEVEL
DESCRIPTION
Level 4
Above and beyond
Student accomplishes Level 3 and goes beyond in some
significant way, such as: questioning or justifying the source,
validity, and/or quantity of evidence.
Level 3
Complete and correct
Student identifies key evidence with the appropriate facts, data and
observations.
Level 2
Almost there
Student includes some, but not all, relevant evidence
BUT student omits key evidence OR provides an insufficient number of
facts, data, and observations.
Level 1
On your way
Student states opinion as facts
Level 0
Student’s response is missing, illegible, or irrelevant.
X
Student had no opportunity to respond.
OR student uses incorrect or irrelevant evidence.
Writing Frame – Recognizing Evidence
I am investigating the following question: _____________________________________
________________________________________________________________________
I have found the following facts, data, and observations that provide evidence about
this question:
1. __________________________________________________________________
_____________________________________________________________________
2. __________________________________________________________________
_____________________________________________________________________
3. __________________________________________________________________
_____________________________________________________________________
Analysis Question 2b
What did he do to provide evidence of the relationship between pellagra and
nutrition?
Be sure to explain how his research provided evidence that supported or disproved his hypothesis.
He observed that people who worked in institutions did not get pellagra but their patients
did.
He observed that the orphans with pellagra who were fed a complete diet got better.
He observed that when orphans who did not have pellagra and were fed a complete diet
they did not get it.
He did an experiment in which he fed Prisoners a poor diet; as a result, 7 prisoners
developed pellagra.
He did another experiment in which then fed those patients a better diet and they got
better..
Analysis Question 4
Compare the steps of the traditional scientific method to the steps Dr. Goldberger followed
to investigate pellagra.
How were the steps the same?
Use Student Sheet 2.3 to help you.
How were the steps different?
Analysis question 5
Fill in the “After” column for statements 3 and 4
only on Sheet 1.1, “Anticipation Guide: Ideas
about Experimental Design.”
Did your thinking change? Explain why or why
not.
Analysis Question 6
To investigate his hypothesis, Dr. Goldberger had prisoners volunteer to be
fed a poor diet; as a result, 7 out of 11 prisoners developed pellagra.
What do you think about Dr. Goldberger’s decision to experiment on
people?
Support your answer with evidence and identify the trade-offs of your
decision. Hint: To write a complete answer, first state your opinion. Provide
two or more pieces of evidence that support your opinion. Then consider all
sides of the issue and identify the trade-offs of your decision.