Normalisation of Deviance: How Unsafe Practices Become the Norm Onboard

14 Jul Normalisation of Deviance: How Unsafe Practices Become the Norm Onboard

The normalisation of deviance is the process by which an unsafe practice, repeated over time without immediate consequences, comes to be accepted as normal within an organisation. In the maritime sector, this cultural drift quietly erodes safety margins, turning risky shortcuts into everyday operating standards. The most effective defence is not a new rule, but a culture that makes it safe to speak up.

What does “normalisation of deviance” mean?

The term was coined by sociologist Diane Vaughan of Columbia University, during her analysis of the Space Shuttle Challenger disaster. Vaughan defines it as the gradual process by which practices or standards that were initially unacceptable come to be accepted: as deviant behaviour is repeated without catastrophic consequences, it becomes the organisation’s social norm.

The crucial point is that this is almost never a sudden or intentional violation. It is a slow drift, often invisible to those living through it, that works its way into organisational culture under the pressure of time, budget, or efficiency. Every time a crew deviates from the “correct” procedure without anything going wrong, it becomes easier to do it again — because last time it worked out fine.

How does the drift unfold onboard a ship?

In the maritime context — and especially in the complex operations of passenger and cruise ships — deviance spreads through a sequence of micro-adaptations rather than a single major breach. The typical cycle unfolds in four stages:

1. Environmental pressure — the crew manages a conflict between competing goals: full compliance with safety checklists, and commercial efficiency (mooring times, shorter port stays, optimised workflows).
2. The first adaptation — to compensate for a shortage of time or resources, a procedural barrier perceived as “redundant” is bypassed.
3. The absence of consequences — the operation ends without incident. The system implicitly “rewards” the shortcut with the achievement of the goal.
4. The redefinition of the standard — the deviation loses its association with risk and is filed away as an “efficient practice”. It becomes the new starting point for the shifts that follow.

This link between operational pressure, cognitive load and error is explored further in our article Why Work Interruptions Harm Performance: What Research Shows.

A telling case: the Costa Concordia

The cruise sector knows one dramatic example of this phenomenon. In January 2012, the Costa Concordia, a cruise ship of the Carnival fleet, capsized off the island of Giglio on the Italian coast, with the loss of 32 lives. The captain deliberately deviated from the official route — a practice in which he and other captains had frequently engaged in order to sail close to the island.

It is a textbook case of normalisation of deviance: a risky manoeuvre, repeated many times without consequences, had become accepted and even celebrated, until it met the unexpected variable. The deviance had become normalised because it had always worked out in the past, and so it was assumed it would work out in the future too.

 

Why does the human mind stop perceiving the risk?

The psychological knot lies in how the brain processes risk feedback. When a potentially dangerous action is repeated without receiving a negative signal — an accident, a reprimand, a near-miss taken seriously — the sense of danger associated with that action gradually fades, until it disappears.

At that point, the real risk shifts from the technical level to the cultural one. The crew does not realise it is operating without a safety margin until the unexpected event occurs. This is why near-misses are such valuable information: each one is a learning opportunity that, if ignored or “celebrated” as luck, is wasted.

I believe the normalisation of deviance is one of the most underestimated risks onboard, precisely because it does not come from negligence, but from habit. When a shortcut produces no consequences, it stops feeling like a risk. It is a silent, almost imperceptible process, and this is exactly where the human factor truly makes the difference: in a crew’s ability to pause, observe, and say out loud what doesn’t add up, before it becomes normal.

— Annalisa Rolandi, Founder and CEO of Maritime Utilia

How can the normalisation of deviance be countered?

The most effective defence is not to add rules — paradoxically, an excess of procedures can accelerate the drift, because it pushes people to look for shortcuts when bureaucracy slows the work down. The real lever is psychological safety: the freedom the crew feels to report anomalies, doubts, or errors without fear of repercussions or isolation.

Several signs of cultural drift can be intercepted before they become dangerous:

• Checklists completed after the operation rather than in real time, experienced as bureaucratic box-ticking rather than as a protective barrier.
• Hierarchical silence, when junior crew members do not question their superiors’ deviations for fear of sanctions or social isolation.
• Tolerance of the near-miss, when a close call is filed away as “good luck” rather than analysed.

This is the ground on which Maritime Utilia’s work is focused. Through its psychological assessment services and its managerial and soft skills training programmes, Maritime Utilia helps companies build onboard environments where reporting is encouraged and the authority gradient does not stifle communication. The link between leadership, trust, and safety is explored further in our articles The Role of Ethical Leadership in Organizations and Safety Leadership and Just Culture.

 

Frequently asked questions

Who coined the concept of normalisation of deviance?
Sociologist Diane Vaughan of Columbia University, in her analysis of the Space Shuttle Challenger disaster. She defines it as the process by which initially unacceptable practices become normal when they are repeated without catastrophic consequences.

Why is the normalisation of deviance dangerous in the maritime sector?
Because it quietly erodes safety margins. Shortcuts repeated without incident come to be seen as efficient practices, until an unexpected variable turns the accumulated risk into a casualty.

How is it prevented onboard?
Not primarily through new rules, but by strengthening the crew’s psychological safety: creating an environment where reporting anomalies and near-misses is encouraged and never punished.