Contributors to Human Error
- Population stereotype
- Performance requirements that exceed human capability
- Design that promotes fatigue
- Inadequate facilities or information
- Difficult tasks
- Dangerous tasks
- Unpleasant tasks
- Repetitive or boring tasks
- Tasks at odds with the person's aptitude
- Stress, Illness, Sleep Deprivation, Injury
One aspect that contributes to human error is a population stereotype. It is a concept relating to cultural expectations. It is the manner in which most people in the population expect something to be done. You might think of it as your intuition or your innate functional understanding of something. If you pick up an iPad you might say you have an intuitive understanding of the interface. You can operate it without having to learn how to operate it.
What the designers have done is to study how people do things and what they expect to happen. Then they design a human-machine interface to support these characteristics. A population stereotype is when these expected functions or innate meaning differ from one population to the next due to cultural factors.
White is the traditional color for a wedding dress in the United States, but in some Asian cultures it is the traditional color worn to a funeral. In the United States the color red is often associated with warning or stopping. That is not necessarily the case in all countries. If, for instance, someone came to the United States from a country where red meant go and don't worry about any possible dangers then a big red button to turn off a machine when it is having a problem may be intuitively understood to start the machine instead.
Another aspect that contributes to human error is when the task required exceeds the person's performance capability. Have you ever had a problem opening a jar of peanut butter? That's not what we are talking about. Perhaps a task requires multitasking and you must keep track of three different targets. When you go to hit one of them and miss because your accuracy is suffering from trying to maintain that level of performance that is considered human error.
Fatigue is another contributor to human error. If using a device ends up fatiguing you or you are fatigued for other reasons such as not enough sleep and you (are you ready for the pun) "drop the ball" then that is considered human error.
A lack of information or inadequate facilities contributes to human error by forcing you to make intuitive or logical guesses as to what you should do. If you do not guess correctly you have made a human error.
A difficult task is hard enough to do without error. The more difficult the task the more prone to error it will be. That is kind of the definition of difficult.
A dangerous task, no matter how necessary, is prone for human error. The more you need to concentrate on something the more you are apt to think about what will happen if you mess up and that distracts you and you mess up. That is the same human response you get when you are told not to think about something and then you can not stop thinking about it.
If a task is unpleasant then you are less likely to give it your full attention. You will be thinking about how you would rather be doing something else or about how bad this task is. That distraction will cause you to make more errors. That is also one of the reasons why bad things tend to happen in an already bad situation.
A boring task does not garner your attention. Your mind wanders and soon you are not giving it the attention it requires. The next thing you know you are committing a human error. A repetitive task may start off as interesting, but after a while it becomes boring as well.
Aptitude is an often underrated characteristic when it comes to performance. Most people know that you will probably do better at something you are naturally good at then other people. But the same can be said for a reverse aptitude. If the task is so against your aptitudes you are more prone to failure than the rest. People with a green thumb can grow an oak tree in a desert. People with a brown thumb can kill the grass in Shea stadium. They don't have the aptitude for it and are actually so naturally bad at it that it takes severe effort and commitment to counteract. That is a situation where human error abounds.
One of the main contributors to human error are personal mental and physical distractions. Being stressed, tired or sick (among other things) reduces your performance capabilities, offer a persistent distraction and otherwise occupies a space in your mental process that may be required for the task. Additionally there are physical issues that may take the task beyond your capabilities to perform and human error occurs like we discussed previously.
Now you may be thinking that if human error is something that only occurs when the error is caused by a person uninfluenced by outside factors that some of these contributors may in fact be outside influences that could be corrected. That is the crux of the human error versus design deficiency argument, because every human error contributor that you can design out of a device or system improves its ergonomics.
