Incorporating Mechanism Maps in TeachingA Strategy for Enhancing Critical Thinking
Jeremy B. Richards, MD, MA
Richard M. Schwartzstein, MD
Shapiro Institute for Education and Research
Beth Israel Deaconess Medical CenterHarvard Medical School
A teaching hospital of
Harvard Medical School
Education is at the heart of patient care.
A teaching hospital ofHarvard Medical School
Disclosures – Dr. Schwartzstein• Perspectives advisory board, New England Journal
of Medicine• Editorial board, Chest• NIH funding for dyspnea research
Disclosures – Dr. Richards• CRICO funding for quality improvement research
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Today’s Goals• Review cognitive science underlying the
development of durable learning• Delineate the dual system model of how we think
when approaching new problems • Describe the role of inductive reasoning in critical
thinking• Demonstrate the difference between classical
concept maps and mechanisms maps• Have you develop a mechanism map
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What is critical thinking?
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What does “work the problem” look like?
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How we think…Dual Processing
• Conscious thought• Unconscious thought
– Cognitive Biases
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Judgment Under UncertaintyTversky and Kahneman, Science, 1974
“…people rely on a limited number of heuristic principles which reduce the number of complex tasks of assessing probabilities…to simpler judgmental operations” which can “lead to severe and systemic errors.”
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Pattern Recognition
Repetition
Executiveoverride
Dysrationaliaoverride Calibration DX
PatientPresentation
PatternProcessor
RECOGNIZED
NOTRECOGNIZED
Type11
Processes
Type22
Processes
Dual ProcessingCourtesy of P. Croskerry, MD, Millennium Conf 2011
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Retention and Use of Knowledge• Long term memory develops in three phases
– Information presentation**– Information processing– Information integration**
• How do you teach?**– Do you look for frameworks for the knowledge to
be learned?– Do you build on prior learning?
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How do students/residents learn?Modified from Harasym et al. 2008
Surface Learning-- New info not linked to
previous knowledge-- Knowledge abundant but
disorganized-- Focus on memorization
and recall-- Learns concepts and facts
without reflection
Deep Learning-- Relates new knowledge to
previous knowledge-- Content organized into
coherent whole-- Focus on problem-solving;
apply, analyze-- Link concepts/principles to
everyday experience
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Deep vs. Superficial Learning
• Link new information to prior learning
• Create frameworks to help students organize and use knowledge
• “Understanding” beyond “knowing”
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Routine vs. Adaptive Expert Mylopoulos M, Regehr G. Med Ed 2007
• Routine Expert – Novel problem adapt problem to the
solution with which they are comfortable– Characterized by speed, accuracy, automaticity
• Adaptive Expert– Use a new problem as a point of departure for
exploration; expand knowledge and understanding
– Characterized by innovation, creativity
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Expertise and Creativity
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How do you solve problems?
You put the key in the ignition, turn the key and the car doesn’t start.
What’s the answer? How do you think about this problem?
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Thinking ApproachesModified from Pottier et al. Med Ed 2010
Inductive Reasoning Deductive Reasoning
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Structure and Use of Traditional Concept Map
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“Mechanism” Maps• Graphic devices to
represent relationships between multiple concepts
• Reinforce mechanistic thinking
• Make links explicit
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Concept vs. Mechanism Map
Pancreatitis
Inflammatory response / cytokine Release
Increased vascularpermeability
Third-spacing Increased abdominalpressures
Decreased preload
Decreased CO
Decreased chest-wallcompliance
IncreasedADH
Increased Palv
Increased dead space
Decreased Na
Decreasedinsulin
Hypovolemia Increased glucose
Decreased DO2
Increasedsympathetic
activation
Increased HR
Increasedanaerobic
metabolism
Increasedlactate
Increased PaCO2
Hypotension
Acidemia
Acute kidneyinjury
Decreased calcium
Pancreatitis
Inflammatory response / cytokine Release
Increased vascularpermeability
Third-spacing Increased abdominalpressures
Decreased preload
Decreased CO
Decreased chest-wallcompliance
IncreasedADH
Increased Palv
Increased dead space
Decreased Na
Decreasedinsulin
Hypovolemia Increased glucose
Decreased DO2
Increasedsympathetic
activation
Increased HR
Increasedanaerobic
metabolism
Increasedlactate
Increased PaCO2
Hypotension
Acidemia
Acute kidneyinjury
Decreased calcium
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Student Comments Support Mechanism MapsMajor themes:
1) Determine causality
“Concept maps helped me look a causality and connections between different parts of the clinical presentation.”
2) Helped identify weaknesses“Concept maps forced me to challenge my understanding
and helped me identify areas that needed more work.”3) Integrated knowledge
“Concept maps helped tie together constellation of symptoms and see how one physiological change can affect multiple organs or cause multiple symptoms.”
4) Helped develop hypotheses“Concept maps made me think of a broad array of causes
for a specific symptom.”
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Mechanism Maps Enhance Exam Performance• Final Exam:
– Final exam was composed of 12 questions– Case-based exam; mostly paragraph answers– Focus of the exam – apply knowledge to solve problems– Maximum possible score = 182
• Overall – 156.0 (std. dev. 12.9) – Range 119-180.5• Group A – 157.5 (std. dev. 11.7)• Groups B and C – 152.3 (std. dev. 13.1)
F-statistic=3.34, p=0.07
priori level of significance of α=0.1.
Veronese et al. Med Teach, In press.
Students’ mechanism maps
Students’ mechanism maps
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Summary• Teaching/learning that emphasizes conceptual
framework supports understanding and application of content
• Inductive reasoning may facilitate adaptive expertise
• Mechanism maps provide a strategy to reinforce basic concepts and teach students how to “work the problem”
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Mechanism map examples• Topic- versus case-based concept maps
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Case-based mechanism map76yo woman with ~10 years of steadily worsening dyspnea, who
now cannot walk more than half a block on flat ground due to breathlessness. She has smoked 10-20 cigarettes a day for 55 years. Recently, she has developed a productive cough and
wheezing. Her exam is notable for a temperature of 98.7, BP 122/84, HR 98, RR 18, O2 sat 90% on room air. Her chest has low-
lying diaphragms and is hyperresonant to percussion. She has decreased breath sounds and expiratory wheezes with an
increased anteroposterior diameter. Heart sounds are distant. Fingernails are not clubbed or cyanotic. She has a 2+ lower
extremity edema.
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Case-based mechanism map
• Identify and highlight core signs and symptoms• Identify pathophysiologic and clinical mechanisms
that link these core signs and symptoms• Begin to link the core signs and symptoms using
pathophysiologic mechanisms• Use linking words when needed• Be open to opportunities to cross-link concepts or
expand the map in new directions
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Case-based mechanism map76yo woman with ~10 years of steadily worsening dyspnea, who
now cannot walk more than half a block on flat ground due to breathlessness. She has smoked 10-20 cigarettes a day for 55 years. Recently, she has developed a productive cough and
wheezing. Her exam is notable for a temperature of 98.7, BP 122/84, HR 98, RR 18, O2 sat 90% on room air. Her chest has low-lying diaphragms and is hyper-resonant to percussion. She has
decreased breath sounds and expiratory wheezes with an increased anteroposterior diameter. Heart sounds are distant.
Fingernails are not clubbed or cyanotic. She has a 2+ lower extremity edema.
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Case-based mechanism mapworsening dyspnea
smoked cigarettes
productive cough wheezing
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Break-out groups• Time to put theory into practice!• Divide into groups of 4-5• Each group will spend the next 20 minutes designing a
mechanism map based on a case vignette• Highlight pathophysiologic mechanisms as they relate
to clinical signs and symptoms• During the process, keep track of pros and cons of
developing a mechanism map
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Break-out groups?• Students were assigned to groups of 3 and instructed
to produce a consensus concept map in response to questions about microbiology
Kinchin I, Hay D. J Adv Nurs 2005;51(2):183–7
Morse D, Jutras F. CBE Life Sci Educ 2008;7(2):243-53
• Learning and performance was higher in students in groups with disparate backgrounds and different knowledge bases
• Peer (and instructor) feedback reinforces learning beyond the act of building a concept map
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Break-out groups• Time to put theory into practice!• Divide into groups of 4-5• Each group will spend the next 20 minutes designing a
mechanism map based on a case vignette• Highlight pathophysiologic mechanisms as they relate
to clinical signs and symptoms• During the process, keep track of pros and cons of
developing a mechanism map
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Case vignetteMr. Green, a 47yo attorney and former heavy drinker, presents
with a 6 month history of marked fatigue and dyspnea on minimal exertion. He tells you, “I feel so tired by lunch time that
I have to go home to sleep.” He has also had decreased exertion, and has cut his daily 2 mile walk to 1 mile, a half mile, and then stopped walking altogether. He cannot lie flat at night
because he awakens 1-2 hours after going to sleep with dramatic shortness of breath. Over the last two weeks he has
only been comfortable sleeping upright in a chair.
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Case vignetteMr. Green, a 47yo attorney and former heavy drinker, presents
with a 6 month history of marked fatigue and dyspnea on minimal exertion. He tells you, “I feel so tired by lunch time that I have to go home to sleep.” He has also had decreased
exertion, and has cut his daily 2 mile walk to 1 mile, a half mile, and then stopped walking altogether. He cannot lie flat at night
because he awakens 1-2 hours after going to sleep with dramatic shortness of breath. Over the last two weeks he has
only been comfortable sleeping upright in a chair.
A teaching hospital ofHarvard Medical School
Physiologic mechanismsConsider using these concepts / mechanisms in your map:
•Preload•Afterload•Sympathetic nervous system•Contractility•Stroke volume•Heart rate
•Diastolic (volume, pressure)•Systolic (volume, pressure)•Systemic vascular resistance•Oxygen delivery•Gas exchange•Hypertrophy