Listen Here:
Click or simply search “Sigma Nutrition” on your podcast platform of choice.
Or listen directly on the Sigma website here.
Introduction
We take a look at critical thinking in science and healthcare, examining how we often fall prey to cognitive biases, emotional reasoning, and flawed thinking. Drawing from six different experts in their respective fields, the episode explores why we sometimes believe we are being rational when in fact our conclusions aren’t truly evidence-based. The discussion spans what genuine evidence-based practice means, how domain expertise matters, and how factors like identity, beliefs, and emotions can derail objective reasoning.
Related resources
- Join the Sigma newsletter for free
- Subscribe to Sigma Nutrition Premium
- Become a member of Alan Flanagan’s Alinea Nutrition Education Hub
- Enroll in the next cohort of our Applied Nutrition Literacy course
- Episodes referenced:
- 416: David Nunan, PhD – Evidence-Informed Health Care: Evidence-based Medicine 2.0
- 247: John Kiely – Scepticism, Cognitive Bias & Applying Science to Practice
- 390: Gil Carvalho MD, PhD – Dairy, Olive Oil & Diet Debates: Understanding Evidence
- 365: David Robert Grimes, PhD – Conspiracy Theories & Bad Information: Why Are We Susceptible?
- 576: The Social Psychology of Health Beliefs and Misinformation – Matthew Facciani, PhD
- SNP11: The Death of Domain Expertise
- [02:56]Dr. David Nunan on evidence-based medicine
- [15:30]Dr. John Kiely on translating research into practice
- [26:10]Dr. Gil Carvallo on emotion and decision making
- [30:10]Dr. David Robert Grimes on webs of belief
- [37:18]Dr. Matthew Facciani identity and belief formation
- [42:31]Dr. Alan Flanagan on domain-specific expertise in nutrition science
The Hosts
Click through to your app of choice to listen and subscribe:
Dr. Alan Flanagan has a PhD in nutrition from the University of Surrey, where his doctoral research focused on circadian rhythms, feeding, and chrononutrition.
This work was based on human intervention trials. He also has a Masters in Nutritional Medicine from the same institution.
Dr. Flanagan is a regular co-host of Sigma Nutrition Radio. He also produces written content for Sigma Nutrition, as part of his role as Research Communication Officer.
Danny Lennon has a master’s degree (MSc.) in Nutritional Sciences from University College Cork, and he is the founder of Sigma Nutrition.
Danny is currently a member of the Advisory Board of the Sports Nutrition Association, the global regulatory body responsible for the standardisation of best practice in the sports nutrition profession.
Introduction to this Episode
We take a look at critical thinking in science and healthcare, examining how we often fall prey to cognitive biases, emotional reasoning, and flawed thinking. Drawing from six different experts in their respective fields, the episode explores why we sometimes believe we are being rational when in fact our conclusions arenʼt truly evidence-based. The discussion spans what genuine evidence-based practice means, how domain expertise matters, and how factors like identity, beliefs, and emotions can derail objective reasoning.
This theme is highly relevant in healthcare, science, and public decision-making because evidence-based decisions save lives and improve outcomes. In medicine and nutrition, professionals must navigate research data, patient values, and context to make sound decisions rather than relying on anecdote or habit. Similarly, policymakers and the public need critical thinking to avoid being misled by pseudoscience or misinformation.
Strengthening our critical mindset helps ensure that guidelines, clinical practices, and public beliefs are grounded in reliable evidence and rational analysis, rather than biases or false claims.
Useful Terminology for this Episode
- Evidence-Based Medicine (EBM) – An approach to clinical practice in which decisions are made based on the best available research evidence combined with clinical expertise and patient values/preferences.
- Cognitive Dissonance – A psychological phenomenon referring to the mental discomfort experienced when holding two or more conflicting beliefs or when new information challenges oneʼs existing beliefs.
- Domain-Specific Expertise – Deep, specialized knowledge and skills in a particular field or subject area. It implies not only knowing the facts of that domain, but also having the analytical tools and experience to interpret evidence in that context.
- Web of Belief – A concept describing how an individualʼs beliefs are interconnected in a network (originating from philosopher W.V. Quineʼs idea). In this “web,” changing one belief can reverberate through others, since beliefs support and justify each other.
- Emotional Reasoning – A cognitive process where a person uses their emotions as evidence for what is true. In emotional reasoning, if something “feels” true or feels right/wrong, the individual concludes it must be true, regardless of objective evidence.
- Identity-Protective Cognition – A form of motivated reasoning where someone rejects or discounts evidence that threatens their group identity or core value.