
Hosted by Gareth Lock at The Human Diver · EN

This episode explores what people really mean when they talk about “human factors” in diving—and why the term can sometimes create more confusion than clarity. It looks at four different ways the phrase is commonly used: blaming “the human factor” when something goes wrong, focusing on what is happening inside the diver such as stress or decision-making, examining the external conditions that shape performance like equipment, procedures, and team dynamics, and finally viewing diving as a complex socio-technical system where people, technology, organisations, and the environment all interact. While the first three approaches can offer useful insights, they often miss the bigger picture. Real learning and lasting safety improvements come from understanding how the whole system works together, not just identifying individual mistakes. By shifting from blame to systems thinking, instructors and divers can better understand why outcomes occur and make meaningful changes that help everyone become better than yesterday.Original blog: https://www.thehumandiver.com/post/four-ways-of-hfTags: THD-English| THD-Education & Content Type

Discussions about diving incidents on social media often follow a predictable pattern: a short, simplified post describes what happened, and comments quickly focus on blaming the individual involved, creating a sense of clear-cut failure and easy lessons. This happens not because people have bad intentions, but because simple, linear stories and knowing the outcome push our brains toward hindsight judgement, making complex situations seem obvious after the fact. As a result, important factors like conditions, pressures, communication, and decision-making context are ignored, limiting real learning. Over time, this blame-focused culture encourages people to share less detail or avoid posting altogether, which removes the very information needed to understand incidents properly. To improve learning, the community needs to shift from asking “what went wrong” to “why it made sense at the time,” and respond to posts with curiosity rather than judgement, creating an environment where fuller, more useful stories can be shared and understood.Original blog: https://www.thehumandiver.com/post/clickbait-trolls-and-commentsTags: THD-English| THD-Learning, Incidents & Just Culture

Over the past decade, diving fatalities have remained stubbornly consistent despite better equipment, more training, and growing participation, suggesting the problem isn’t just technical or individual error. Current safety approaches focus on equipment, skills, and counting deaths, but often ignore deeper issues like communication, teamwork, decision-making, and the wider system divers operate in. Research shows that most contributing factors in incidents come from these “upstream” conditions—such as training culture, social pressure, and organisational practices—rather than the diver’s final actions. A major gap is the lack of training and assessment in non-technical skills, which are critical for managing real-world situations under pressure. At the same time, diving lacks an effective system for learning from incidents, as divers are reluctant to report issues to organisations they believe won’t act on them. To improve safety, the industry needs a shared language around human performance, better systems for collecting and learning from data, and a culture that supports open, blame-free discussion—because without addressing these deeper factors, meaningful change is unlikely.Original blog: https://www.thehumandiver.com/post/why-does-nothing-changeLinks: Rebreather fatality documentation from RF4.0: https://indepthmag.com/rebreather-forum-4-proceedings-are-available-for-free-download/DCS study from DAN: https://journals.viamedica.pl/international_maritime_health/article/view/108038If Only… documentary: https://www.thehumandiver.com/ifonlyLinnea Mills case: https://www.thehumandiver.com/post/linnea-mills-death-hf-systems-lensDivers Alert Network reporting: https://dan.org/research-reports/research-studies/diving-incident-reporting-system/BSAC reporting: https://www.bsac.com/home/DOSA reporting: https://duikongevallen.nl/LEODSI and PETTEOT: https://www.thehumandiver.com/post/what-is-leodsi-petteotBlogs about learning from incidents: https://www.thehumandiver.com/blog/category/learning-JC-incidentsTags: THD-English| THD-Learning, Incidents & Just Culture

This final blog explores what the research means and how the diving community can realistically improve learning and safety. It argues that the problem is not broken individuals but a system that quietly encourages blame and silence, making it hard for divers to share honest stories about mistakes and near-misses. Fear—of legal action, criticism, or damage to reputation—plays a big role, even when that fear is not based on real outcomes. The result is weak feedback loops, where lessons from real experiences never reach the people who design training or shape the culture. The blog suggests shifting focus from the idea of a formal “just culture” to a more practical “culture of justness,” where fairness, understanding, and learning are encouraged at a local level by respected leaders. It also highlights how sharing more context reduces blame and improves learning, but notes that most divers are never taught how to do this. While there is no single fix, the way forward includes clearer language, better-designed reporting systems, role modelling by instructors and experienced divers, and introducing honest discussions about incidents into training. Ultimately, meaningful change will come from gradually shifting behaviours and norms, so that sharing real experiences becomes normal, supported, and valued across the diving community.Original blog: https://www.thehumandiver.com/post/msc-part-3-the-outcomesLinks: Part 1: https://www.thehumandiver.com/post/msc-part-1-the-problem-spacePart 2: https://www.thehumandiver.com/post/msc-part-2-the-data-and-resultsThe full thesis, Storytelling to Learn: What Happens Underwater, Stays Underwater, was submitted in partial fulfilment of the requirements for the MSc in Human Factors and System Safety at Lund University, 2024. Gareth Lock is the founder of The Human DiverReferences:Dekker, S. (2009). Just culture: Who gets to draw the line? Cognition, Technology & Work, 11(3), 177–185. https://doi.org/10.1007/s10111-008-0110-7EC. (2014). Regulation (EU) No 376/2014 of the European Parliament and of the Council of 3 April 2014. European Commission.Exley, S. (1986). Basic cave diving: A blueprint for survival. National Speleological Society – Cave Diving Section. https://nsscds.org/wp-content/uploads/2018/05/Blueprint-for-Survival.pdfHeffernan, M. (2011). Wilful blindness: Why we ignore the obvious. Simon and Schuster.Hoffman, B. G. (2012). American icon: Alan Mulally and the fight to save Ford Motor Company. Crown.Rasmussen, J. (1997). Risk management in a dynamic society: A modelling problem. Safety Science, 27(2–3), 183–213.Tags: THD-English| THD-Learning, Incidents & Just Culture

This blog explains how a mixed-methods study explored why divers struggle to share honest, learning-focused stories about incidents. Using a large international survey, focus groups, and expert interviews, the research found that storytelling is strongly shaped by organisational culture, fear, and trust. Many divers—especially instructors—fear legal consequences, criticism, or damage to their reputation, which stops them from speaking openly, particularly in public settings. At the same time, there is confusion about key ideas like what counts as an “incident,” what “risk” really means, and what a “just culture” looks like, with very few divers linking incidents to learning. The study also showed that when stories include more context, people are less likely to judge and more likely to learn, but most divers are not taught how to do this. Overall, the findings suggest the diving community knows that sharing near-misses and building a just culture would improve safety, but lacks the trust, understanding, and organisational support needed to make that happen.Original blog: https://www.thehumandiver.com/post/msc-part-2-the-data-and-resultsLinks and references: British Diving Safety Groiup: https://bdsg.org.uk/Chan, W. T.-K., & Li, W.-C. (2023). Development of effective human factors interventions for aviation safety management. Frontiers in Public Health, 11, 1144921. https://doi.org/10.3389/fpubh.2023.1144921EC. (2014). Regulation (EU) No 376/2014 of the European Parliament and of the Council of 3 April 2014. European Commission.Reason, J. (2016). Managing the risks of organizational accidents. Routledge. https://doi.org/10.4324/9781315543543Tags: THD-English| THD-Learning, Incidents & Just Culture

This episode introduces the problem behind learning in diving safety, using the 2020 death of Linnea Mills to highlight how incidents are often caused by deeper system issues, not just individual mistakes. While near-misses and accidents happen regularly in diving, most are never shared or analysed, meaning valuable lessons are lost. Unlike industries such as aviation or healthcare, diving lacks strong reporting systems, regulation, and reliable data, so decisions are often based on uncertainty rather than evidence. Existing reports tend to focus on immediate causes like equipment failure or diver error, but miss the wider social, organisational, and environmental factors that shape outcomes. The episode argues that meaningful learning comes from “context-rich” stories that explain not just what happened, but why it made sense at the time. Drawing on safety research from other industries, it highlights the need for a stronger reporting culture, psychological safety, and system-level thinking to improve learning and prevent future incidents.Original blog: https://www.thehumandiver.com/post/msc-part-1-the-problem-spaceReferences: Dekker, S. (2017). Just culture: Restoring trust and accountability in your organization (3rd ed.). CRC Press, Taylor & Francis Group.Drupsteen, L., & Guldenmund, F. (2014). What is learning: A review of the safety literature to define learning from incidents, accidents and disasters. Journal of Contingencies and Crisis Management, 22(2), 81–96. https://doi.org/10.1111/1468-5973.12039EC. (2014). Regulation (EU) No 376/2014 of the European Parliament and of the Council of 3 April 2014. European Commission.Gigerenzer, G. (2014). Risk savvy. Viking. https://www.amazon.co.uk/Risk-Savvy-Make-Good-Decisions/dp/1846144744Lock, G. (2011). The application of the Human Factors Analysis and Classification System (HFACS) to improve diving safety. https://drive.google.com/file/d/1Iz3qRRyo2NjdiBGbPcRhj14NoCTuuM4/view?usp=share_linkMills v Gull Dive Center PADI (2022). https://www.scribd.com/document/555406095/Mills-v-Gull-Dive-Center-PADI-2nd-Amended-ComplaintOrlady, H. W., & Orlady, L. M. (2017). Human factors in multi-crew flight operations (1st ed.). Routledge.Reason, J. (2016). Managing the risks of organizational accidents. Routledge. https://doi.org/10.4324/9781315543543Snowden, D. (2002). Complex acts of knowing: Paradox and descriptive self-awareness. Journal of Knowledge Management, 6(2), 100–111. https://doi.org/10.1108/13673270210424639Waring, J. J. (2005). Beyond blame: Cultural barriers to medical incident reporting. Social Science & Medicine, 60(9), 1927–1935. https://doi.org/10.1016/j.socscimed.2004.08.055Tags: English| Learning, Incidents & Just Culture

This episode examines a 2012 triple fatality at Cenote Chac Mool in Mexico using a Human Factors approach, showing how accidents are rarely caused by a single mistake but by a combination of small, interacting factors. A guide took two recreational divers beyond safe limits into an overhead cave environment without a continuous guideline, and all three ran out of gas and died. Instead of simply blaming the guide, the analysis explores how things made sense at the time, including authority gradients that stopped the divers from questioning decisions, fatigue from multiple dives, pressure to show something impressive, and increasing task load in a complex environment. Using the PETTEOT framework, the case highlights how people, environment, equipment, organisational culture, and time pressures combined to reduce safety margins until there was no capacity left to recover. The key lesson is that safety depends on understanding these system interactions, building psychological safety so people can speak up, and reinforcing clear rules and preparation to prevent small, “normal” deviations from turning into fatal outcomes.Original blog: https://www.thehumandiver.com/post/chac-mool-triple-diving-fatalityLinks: Full CREER manual: https://creer-mx.com/wp-content/uploads/2024/03/Manual-for-Cenote-Dive-Guides-vs010324.pdfThe Thumb rule: https://www.thehumandiver.com/post/top-tips-for-diving-instructors-psychological-safety-and-the-thumb-ruleLearning from Emergent Outcomes course waiting list: https://www.thehumandiver.com/lfeoTags: English| Learning, Incidents & Just Culture

This episode explores the fatal case of 18-year-old Linnea Mills to show how visible hazards can go unnoticed when an instructor lacks the mental capacity to recognise them. Linnea was overweighted, unable to inflate her drysuit, and using equipment that couldn’t provide enough lift—risks that seem obvious in hindsight but were missed due to a combination of inexperience, time pressure, unfamiliar gear, and commercial expectations. Using models like ECOM and COCOM, the episode explains how an instructor’s attention can be consumed by immediate tasks, leaving no capacity to monitor the bigger picture or reassess whether a dive should proceed. This isn’t about blaming an individual, but understanding how systems, workload, and limited experience can overwhelm decision-making. The key lesson is that effective instructors don’t just rely on skill, but on preparation—setting clear plans, checks, and limits before the dive—to protect their ability to recognise problems when it matters most.Original blog: https://www.thehumandiver.com/post/the-obvious-thing-nobody-noticedLinks: Part 1: https://www.thehumandiver.com/post/the-picture-went-darkThe Linnea Mills case: https://www.thehumandiver.com/post/linnea-mills-death-hf-systems-lensTags: English| Sense-making, Decision-making, & Psychology

This episode explores why divers don’t truly “lose” situation awareness, but instead run out of the mental capacity needed to maintain it. Through the story of James on a challenging wreck dive, it shows how increasing demands—like current, task focus, and effort—can quietly narrow attention until the bigger picture is lost, even when skills and training are sound. Using two human factors models, COCOM and ECOM, the discussion explains how control shifts from broad, strategic thinking to narrow, reactive behavior as workload rises, and how different layers of awareness—from basic task execution to overall planning—can break down under pressure. It highlights that mistakes are often not about poor decisions, but about limited cognitive resources in the moment. The episode also emphasizes the importance of good preparation, clear decision thresholds, teamwork, and deliberate pauses to manage workload, while showing how reflection after the dive helps improve future performance. Ultimately, it reframes the difference between novice and experienced divers as the ability to manage attention and maintain the bigger picture, not just technical skill.Original blog: https://www.thehumandiver.com/post/the-picture-went-darkLinks: A 2026 study in Safety Science by Woltjer and colleagues: https://www.sciencedirect.com/science/article/pii/S0925753526000822Part two: https://www.thehumandiver.com/post/the-obvious-thing-nobody-noticedTags: English| Sense-making, Decision-making, & Psychology

Divers make many decisions quickly, often without realising it, by using heuristics—mental shortcuts that help us act fast when time and information are limited. These shortcuts are essential and often effective, especially with experience, but they can also lead to predictable errors called biases when used in the wrong situation. Common examples include relying too much on recent experience, sticking to an original plan despite changing conditions, or only noticing information that supports what we already believe. In diving, where conditions vary and feedback is often limited, these biases can quietly increase risk. The key is not to avoid intuition, but to understand when it might be misleading and to slow down when needed. Tools like checklists, realistic training, and open team communication help balance fast thinking with more careful decision-making, improving safety and helping divers make better choices underwater.Original blog: https://www.thehumandiver.com/post/shortcuts-errors-and-the-gapLinks: Gigerenzer’s push for people to be “risk savvy”: https://www.jasoncollins.blog/posts/nudging-citizens-to-be-risk-savvyBlog about the Scylla wreck tragedy: https://www.thehumandiver.com/post/scylla-wreck-penetration-leodsiBlog about the IJN Sata incident: https://wreckedinmyrevo.com/2023/11/16/close-call-on-the-ijn-sata-palau-120-fsw/Tags: English| Sense-making, Decision-making, & Psychology