Complacency can be described as a feeling of self-satisfaction accompanied by a loss of awareness of potential dangers. Such a feeling often arises when conducting routine activities that have become habitual and which may be “considered”, by an individual (sometimes by the whole organisation), as easy and safe. A general relaxation of vigilance results and important signals will be missed, with the individual only seeing what he, or she, expects to see. Complacency can also occur following a highly intense activity such as recovering from a possible disaster; the relief felt at the time can result in physical relaxation and reduced mental vigilance and awareness. This particular psychological experience is referred to as a Lacuna.
Whilst too much pressure and demand causes over-stress and reduced human performance, too little results in under-stress, boredom, complacency and reduced human performance. It is therefore important, when conducting simple, routine and habitual tasks, and when fatigued, to maintain an adequate, or optimum, level of stress through different stimulation. Always expect to find a fault! Following written instructions, and adhering to procedures that increase vigilance, such as inspection routines, can provide suitable stimulus. It is important to avoid: working from memory; assuming that something is ok when you haven’t checked it; and, signing off work that you are unsure has been completed. Teamwork and mutual cross-checking will provide adequate stimulus when fatigued.