In the skill-based mode, the individual is able to function very effectively by using ‘pre-programmed’ sequences of behavior which do not require much conscious control. It is only occasionally necessary to check on progress at particular points when operating in this mode. The price to be paid for this economy of effort is that strong habits can take over when attention to checks is diverted by distractions, and when unfamiliar activities are embedded in a familiar context. This type of slip is called a ‘strong but wrong’ error.