
Counter-Errorism in Diving: Applying Human Factors to Diving
Human factors is a critical topic within the world of SCUBA diving, scientific diving, military diving, and commercial diving. This podcast is a mixture of interviews and 'shorts' which are audio versions of the weekly blog from The Human Diver.
Each month we will look to have at least one interview and one case study discussion where we look at an event in detail and how human factors and non-technical skills contributed (or prevented) it from happening in the manner it did.
Latest episodes

Mar 1, 2025 • 16min
SH152: The Bend is Uninteresting...The Related Decisions Are Much More So
In this episode, we explore a personal account of a Gareth’s experience with decompression sickness (DCS) and the critical decision-making process that followed. The story dives into the internal monologue, biases, and stigmas surrounding DCS, highlighting how emotions and uncertainties influence risk-based decisions. We also examine industry practices, the importance of creating a psychologically safe culture for discussing incidents, and the need for better preparedness when things go wrong. This episode challenges listeners to reflect on their own decision-making and encourages a shift toward curiosity and learning in the diving community.
Original blog: https://www.thehumandiver.com/blog/the-bend-is-uninteresting-the-related-decisions-are-much-more-so
Links: PACE model: https://gcaptain.com/graded-assertiveness-captain-i-have-a-concern/
Prospect Theory: https://www.jstor.org/stable/1914185
Blog about Normalisation of Deviance: https://www.thehumandiver.com/blog/being-a-deviant-is-normal
Distancing through Differencing: https://www.researchgate.net/profile/David_Woods11/publication/292504703_Distancing_through_differencing_An_obstacle_to_organizational_learning_following_accidents/links/5742fb1808ae9ace8418b7ea/Distancing-through-differencing-An-obstacle-to-organizational-learning-following-accidents.pdf
Tags: English, Decision Making, Gareth Lock

Feb 26, 2025 • 9min
SH151: When the holes line up...
In this episode, we explore Professor James Reason's Swiss Cheese Model, which helps explain how incidents occur when multiple safety barriers fail at different levels within a system. We discuss how organizational, supervisory, and individual errors can combine to create accidents, and how the holes in these barriers move and shift over time. Using dynamic models, we highlight that safety is an emergent property of a system, where small errors accumulate and can lead to larger, more significant failures. We also examine the role of human error, risk management, and attention to detail in preventing accidents and emphasize the complexity of real-world systems, where multiple factors often lead to a critical mass of failure before an incident happens.
Original blog: https://www.thehumandiver.com/blog/when-the-holes-line-up
Links: Animated simple Swiss Cheese model: https://vimeo.com/326723142
Big Hole model: https://vimeo.com/326723122
Little Hole model: https://vimeo.com/326723109
Tags: English, Gareth Lock, Human Factors, Incident Investigation

Feb 22, 2025 • 13min
SH150: Are you a good enough diver?
In this episode, we dive into the concept of "good enough" in diving and how it relates to decision-making, risk, and safety. We explore why terms like "safe" and "good" are subjective and often influenced by context, experience, and social pressures, rather than absolutes. Using real-life examples, we discuss how divers weigh trade-offs between efficiency and thoroughness, balancing time, money, and risk to make decisions in uncertain situations. By understanding the biases and constraints that shape our choices, we can better assess what "good enough" means in different scenarios and improve through shared stories and context-rich learning.
Original blog: Spiderman drawing video: https://youtu.be/x9wn633vl_c
Blog from Steve Shorrock: https://humanisticsystems.com/2016/12/05/the-varieties-of-human-work/
Efficiency-Thouroughness Trade Off: http://erikhollnagel.com/ideas/etto-principle/index.html
Latent Pathogens from James Reason: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1117770/
Outcome bias: https://en.wikipedia.org/wiki/Outcome_bias
Tags: English, Gareth Lock

Feb 19, 2025 • 10min
SH149: 'Choices': Guaranteed small loss or a probable larger loss, injury or fatality?
In this episode, we explore how decision-making under uncertainty plays a crucial role in scuba diving, drawing insights from Prospect Theory and real-life scenarios. We discuss how psychological factors, like loss aversion, influence divers to take risks they might otherwise avoid—whether it's diving with faulty gear after weeks of being unable to dive or dealing with pressures during high-profile expeditions. Highlighting examples from both individual dives and operational standards in dive centers, we examine the balance between minimizing loss and managing uncertainty. Finally, we emphasize the importance of teamwork, robust communication, and standardization to mitigate risks, ensuring safer and more informed diving decisions.
Original blog: DOSPERT Study: https://papers.ssrn.com/sol3/papers.cfm?abstract_id=1301089
Near death experience in Truk lagoon: https://www.scubaboard.com/community/threads/complacency-kills-its-not-just-an-empty-threat.567481/
Tags: English, Decision Making, Gareth Lock, Human Factors, Risk

Feb 15, 2025 • 16min
SH148: Risk of diving fatality is 1:200 000. However, you cannot be a fraction of dead…!
In this episode, we explore how risk is perceived and managed in diving, where emotions, biases, and mental shortcuts often outweigh logic and statistics. Diving fatalities are statistically rare, but those numbers don’t resonate emotionally—our decisions are more influenced by stories and personal experiences. Through real-life examples, we unpack biases like availability bias, outcome bias, and the “turkey illusion,” showing how these distort our understanding of risks. The discussion also highlights strategies for improving risk management, such as using checklists, planning and debriefing effectively, and sharing experiences to enhance collective learning. Join us to rethink how we approach uncertainty and decision-making in diving and beyond.
Original blog: https://www.thehumandiver.com/blog/riskoffatality
Links: Fatalities COnference Procceedings: https://www.diversalertnetwork.org/files/Fatalities_Proceedings.pdf
Numbers don;t have the same emotional relevance as stories: https://hbr.org/2003/06/storytelling-that-moves-people
Risk of dying from a shark attack: https://www.floridamuseum.ufl.edu/shark-attacks/odds/compare-risk/death/
Behavioural economics: https://www.behavioraleconomics.com/resources/introduction-behavioral-economics/
Prospect theory: https://www.behavioraleconomics.com/resources/mini-encyclopedia-of-be/prospect-theory/
Video about normalisation of deviance: https://vimeo.com/174875861
4 T’s of risk management: https://www.facebook.com/groups/1612046102342961/permalink/2160646497482916/
How it makes sense for “stupid” decisions: https://www.facebook.com/gareth.lock.5/videos/10155465887236831/
Tags: English, Gareth Lock

Feb 12, 2025 • 9min
SH147: Dive safety leads to nothingness...and nothingness is unemotive!
How do you measure safety in diving? This episode dives into a real story of a dive team that adapted to an emerging safety risk when two divers, certified but inexperienced in drysuits and challenging conditions, showed signs of stress. Through situational awareness, communication, and teamwork, the team adjusted their plan, choosing a safer dive site where the less experienced divers could build confidence. The story highlights how safety isn’t about luck or strict rule-following but proactive decision-making and collaboration. We explore how divers can develop the skills to create safety and why “nothing happening” often means someone made it happen.
Original blog: https://www.thehumandiver.com/blog/safety-is-nothingness
Tags: English, Decision Making, Gareth Lock, Human Factors, Leadership, Safety, Teamwork

Feb 8, 2025 • 8min
SH146: Why ‘everyone is responsible for their own risk-based decisions’ isn’t the right approach to take to improve diving safety.
In this episode, we explore the decision-making challenges in diving, sharing a personal story of risky dives and lessons learned. A diver reflects on their early diving experiences, from breaking training depth limits to encountering equipment failures at 30m, and how a lack of knowledge and overconfidence contributed to risky choices. We discuss the importance of understanding context when evaluating incidents, avoiding hindsight bias, and learning from mistakes to improve safety. Diving involves inherent risks, but by fostering curiosity, sharing lessons, and acknowledging uncertainties, we can create a safer and more informed diving community.
Original blog: https://www.thehumandiver.com/blog/responsible-but-not-informed
Tags: English, Decision Making, Gareth Lock, Human Factors, Risk Management

Feb 5, 2025 • 7min
SH145: Cognitive Dissonance - Why you are right and I am wrong...Or are you?
In this episode, we dive into cognitive dissonance—the psychological discomfort of confronting facts that challenge our beliefs—and how it impacts decision-making and safety in diving. Drawing on insights from Black Box Thinking by Matthew Syed and examples from aviation, justice, and diving, we explore why even highly educated individuals can resist change to protect their reputation. From misconceptions about Nitrox and gas planning to biases in equipment and training preferences, we examine common examples in diving and discuss how human factors can improve safety. We also share practical steps to reduce cognitive dissonance, embrace learning from failure, and foster open-mindedness in the diving community.
Original blog: https://www.thehumandiver.com/blog/cognitive-dissonance
Links: Ditching in the Hudson of Cactus 1549: https://en.wikipedia.org/wiki/US_Airways_Flight_1549
Story about cult foollowers expecting a UFO: https://www.minnpost.com/second-opinion/2011/04/when-facts-fail-ufo-cults-birthers-and-cognitive-dissonance
“Unintended co-ejaculators”: https://ethicsunwrapped.utexas.edu/cognitive-dissonance-case-unindicted-co-ejaculator
Examples of cognitive dissonance: https://en.wikipedia.org/wiki/Cognitive_dissonance
Tags: English, Decision Making, Gareth Lock, Human Factors

Feb 1, 2025 • 8min
SH144: Just another brick in (under) the wall...taking action
In this episode, we explore the gap between knowledge and action, focusing on how even small, intentional changes can lead to significant improvements in safety and performance. Drawing from examples like the WHO Safe Surgical Checklist and lessons from diving, we highlight the importance of applying what we know—whether through simple tools like checklists and debriefs or by understanding decision-making and systemic issues. Alongside a personal story about working with a coach to turn knowledge into impactful action, we challenge listeners to reflect: what will you do to turn your insights into meaningful change?
Original blog: https://www.thehumandiver.com/blog/anotherbrickinthewall
Links: CAP 737 http://publicapps.caa.co.uk/modalapplication.aspx?appid=11&mode=detail&id=6480
IOGP Doc 502 https://www.iogp.org/bookstore/product/guidelines-for-implementing-well-operations-crew-resource-management-training/
Non-technical skills for surgeons: https://www.rcsed.ac.uk/professional-support-development-resources/learning-resources/non-technical-skills-for-surgeons-notss
The Castle: http://www.thisiscolossal.com/2018/02/the-castle-by-jorge-mendez-blake/
World Health Organisation Safe Surgical Checklist: https://www.nejm.org/doi/full/10.1056/NEJMsa0810119
Semmelweis: https://en.wikipedia.org/wiki/Ignaz_Semmelweis
Distancing through differencing: https://www.researchgate.net/publication/292504703_Distancing_through_differencing_An_obstacle_to_organizational_learning_following_accidents
Tags: English, Decision-Making, Gareth Lock, Human Factors, Non-Technical Skills

Jan 29, 2025 • 13min
SH143: 'Entirely Predictable' vs 'Managing Uncertainty': How many rolls on the dice?
In this episode, we delve into the complexities of managing risk and uncertainty in diving, challenging the notion that accidents are "entirely predictable." Unlike measurable risks, diving involves countless variables that create uncertainty, often managed through mental shortcuts and biases. We discuss how hindsight bias, overconfidence, and peer pressure can cloud judgment, leading to poor decisions. Effective feedback, teamwork, and tools like checklists can reduce uncertainty, while debriefs and learning from others’ mistakes are crucial for improvement. Tune in to explore how divers can navigate uncertainty to enhance safety and performance in this high-stakes environment.
Original blog: https://www.thehumandiver.com/blog/uncertainty-vs-predictable
Links: Risk vs Uncertainty: http://www.mindtherisk.com/literature/67-risk-savvy-by-gerd-gigerenzer
Thinking, Fast and Slow: https://en.wikipedia.org/wiki/Thinking,_Fast_and_Slow
Blog about the Dunning Kruger effect: https://www.thehumandiver.com/blog/incompetent-and-unaware-you-don-t-know-what-you-don-t-know
Blog about biases: https://www.humaninthesystem.co.uk/blog/i-am-biased-you-are-biased-we-are-all-biased
Tags: English, Decision Making, Gareth Lock, Risk