Posted by: David Cant | February 5, 2009


Very few accidents are caused by wilful disobedience of health and safety rules. There are two aspects of the mind’s behaviour that impose limitations on how effectively people can follow procedures. You should bear these in mind when devising any health and safety regime.

Firstly, the mind can hold only seven (plus or minus two) pieces of information at any one time. People will
often notice hazards around a worksite and make a mental note to do something about it in due course. They will forget about the hazard they have spotted almost as soon as they become involved in another task.

Because of this, it is extremely important to keep workplaces tidy. Trips and slips are an extremely common cause of accidents so set rules that require people to clean up after them, not to leave it until later.

Also take account of this feature of the mind when devising step-based procedures. If the number of steps is more than six or seven you should issue a checklist to operatives.

Secondly, the mind has several modes. Beside fully conscious thought (‘beta’ mode) the brain also moves into ‘alpha’ sleep which is characterised by a different frequency of brainwaves. Alpha sleep happens to all of us – it is taking place at the times when we are doing one thing in an automatic fashion whilst thinking about something completely different. Alpha sleep is typically induced when people undertake routine, nonthreatening activities.

Alpha sleep is necessary – it is part of the way the brain manages itself. The amount of alpha sleep varies depending on the person and the activity they are undertaking. For many people it may occur for 20% of their working day. Alpha sleep is synonymous with ‘day dreaming’.

Although people are roused very quickly from alpha sleep whenever a threat is perceived, they are less aware than normal of hazards whilst in that mode. Consider the implications of alpha sleep when devising procedures. Tasks that are boring and repetitive will maximise the amount of alpha sleep.

Try to provide stimulating and variable work in order to minimise the amount of time people spend in alpha sleep. Take extra care to eliminate hazards in environments where alpha sleep is more likely. In particular, take steps to ensure a tidy workplace.


As a general rule 20% of people will obey all instructions and 20% of people will disobey all instructions. The middle 60% will be pulled one way or the other depending on the culture of the organisation.

Health and safety systems should be devised so that the middle 60% are influenced towards compliance. The bottom 20% will therefore seem further adrift from the norms and can more easily dealt with.
People will generally do something by habit (a ‘cognitive shortcut’) after about 21 days of repetitive learning.

The objective of any health and safety regime should be to use this learning process to establish and reinforce positive behaviour so that it becomes habitual. The simplest technique to achieve this objective is termed ‘reminders’.

After you have introduced any new system, establish a system of frequent reminders and of challenging everybody you see not following the rules. Make these reminders friendly and brief wherever possible.

Try to make reminders in the form of ‘interrogative’ questions that invite people to consider the issues themselves (‘How do you think we could reduce the chances of you falling off that ladder?’). After three weeks or so the good habits should have become established and the reminders should be considerably less necessary.

I hope you find this article interesting and informative.

Im off for nap now!!!


  1. […] Th­e rest is h­ere: BEH­A­VIO­URA­L­ A­S­P­ECTS­ O­F H­EA­L&… […]

  2. Hi,

    Very informative article on Alpha sleep. I do agree that alpha sleep occurs while doing any routine work or while doing automated work. I didn’t know about it in this much detail. Thanks for sharing useful information.

  3. First of all thanks for such wonderful information. I have visited your blog first time but I will come again to get something new from you.

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