3.0 THE REALITY
Behavior is one of the components of almost every injury. If we took the people out of the picture there would be no real injuries to speak of. This said, there are virtually no behaviors executed by anyone in pursuit of an injury. So the question that Behavioral science gives us is why people do things that enhance the chance of an injury occurring.

Another frequent component associated with injury is the facility or task design. These are the physical constraints built into the design that form the physical working environment for accomplishing task. Design shortcomings can negatively or positively impact the performance of a desired behavior that may be recognizable to the observer with basic HFE knowledge. Also, here is where the BBS and HFE processes can work together to improve the design, provided the design flaws are recognized and communicated back to the design engineer or to the design engineering process.

The conditions that increase the likelihood of a certain outcome are called risk factors. These are design-related that increase the likelihood of developing a work-related musculoskeletal disorder, also called repetitive stress illness or cumulative trauma disorders.
Example risk factors, associated with the design, that can positively or negatively impact behavior are as follows:
Awkward posture - For each joint in the body, there is a range of motion which is considered neutral or non-stressful. For example, any flexing, bending or twisting of the wrist takes it out of neutral (straight) posture.
Repetitive motions - Movements that are frequently repeated will increase risk. Finger movements at keyboard and mouse are examples.
Forceful motions or exertions -Activities involving forceful motions can increase MSD risk. Examples are gripping a pen too hard or striking the keys of a keyboard too forcefully.
Contact Stress - Pressure applied to a nerve can damage it. An example is resting the wrist of the hand on the sharp edge of a table, which applies excessive pressure to the median nerve coming out of the wrist.
Sustained posture - Any posture, even neutral, can be stressful if it is sustained over long periods. This is most often noticed when the neck, back or shoulder are held in one position for an extended time.

There are three types of behaviors that make up the pool of at risky behavior in any work environment and different types of interventions to deal with these very different types of behavior. It is also the case that the same behavior can fall into any of the three categories at any time depending on the circumstances. The three types of behavior are Enabled behavior, Non-Enabled behavior and, Difficult behavior.

3.1 Enabled Behavior
This is behavior that the employee has discretionary control over. This is not to say that there are very valid and insidious reasons that the employee would not execute it properly. For example, an improperly designed task may introduce certain risk factors that may cause discomfort and possibly injury, which would likely negatively impact the desired behavior. However, it may not always be so overt a barrier to doing it the right way. In most cases the reason for the employee doing this behavior in a risky manner may seem very benign. This is due to, for the most part, to the fact that they have done it many time for long periods with no adverse consequences. In fact, when it is done in the risky manner, it produces some very powerful positive consequences. Examples of these positive consequences are speed, ease, or less work, etc. In most of these cases changing the physical system is not going to yield much change.

3.2 Non-Enabled Behavior
This is the second and polar opposite of enabled behavior. This is a behavior the employee is not in control of. The system allows for one option, in the case of safety, usually that option is not the correct or least risky one. These situations demand some type of intervention strategy. This strategy almost always requires HFE. Without some formal change in the system the behavior has little or no chance of being changed.

3.3 Difficult Behavior
This behavior is one that crosses both of the above categories and is an interesting mix of both systems issues and perceptions. In managing risk in the difficult category the issue seems to be the risk-to-effort ratio. When doing something the correct way involves a lot of effort, or a level of preciseness that is perceived unrealistic, and if the perception of danger is not acute, the employee is very likely to improvise and not take the precautions necessary to avoid exposure.
An example would be the employee that jumps up on their chair or desk to change the light bulb above the desk. We all know that using a ladder would be best. What the employee knows is that to use the ladder they have to go down stairs, find the janitor, get the key to the supply room, unlock it, get the ladder, climb to the second floor, use the ladder then reverse all of the previous steps. This behavior is difficult enough to overshadow the risk in the employee’s mind.
Another example was a machine that had identically designed controls on both sides of the operator’s console for different functions. The operator would frequently engage the wrong control. The operator had to be one hundred percent alert to what they were doing to prevent a mishap. They had informally developed a method for use of the controls that prevented them from being used without breaking the train of thought.

https://docs.neb-one.gc.ca/ll-eng/llisapi.dll/fetch/2000/904...