The ergonomics aspects of a product are intimately linked to the positive or negative experience that users will get from it. Understanding the main types of ergonomics allows us to understand how to design a holistic experience for all the people who will interact a product.

Physical ergonomics

Physical ergonomics refers to the physical and physiological capabilities of users when dealing with a product. Historically it is the most known branch of ergonomics by the general public, it is often associated with comfort of use but not only.
Physical ergonomics studies the relationship between the body and a machine. The first goal of these studies was to avoid musculoskeletal disorders (MSD) during factory work.

Standards have been defined to help engineers design products in line with theoretical human flexibility, but this has not been enough. It was also necessary to take into account the real uses according to the activity’s contexts. For that, standards are inefficient, we must see the users in their environment.

The standards make it possible to make a flashlight that has a good grip, that fits well in the hand and lights up with a button placed near the thumb. The observation of the field allows to discover that the users put it in the mouth to light themselves while having the hands free to work; taking into account this way of using the tool allows to adapt it to the users and to make it really ergonomic.

Physical ergonomics is linked to product design. Taking into account what you can theoretically and actually do with an object ensures a good user experience. This is something more easily verifiable for physical products than for applications and software because these virtual products are used on standardized physical machines: smartphones and computers.

However, if the designed interface forces users to multiply mouse movements and clicks for the slightest action, it is not impossible to develop MSD using computer software. At this point, the user experience is impacted by the physical ergonomics even if the graphical interface is well designed.

Cognitive ergonomics

Cognitive ergonomics refers to the understanding of systems by users. It studies the psychological aspect of users when faced with a physical or digital interface.

It is the ergonomics that is most directly linked to Ux design because it shares the same goal of designing interfaces that are easy and pleasant to use.

Historically, it is linked to aviation. Following the development of aeronautics during the world wars and the unfortunate crashes during the following decades, we tried to understand how pilots thought in a flight situation. Cockpits were simplified, controls were distinguished by visual aids that lightened the mental load and limited errors.

The discipline was then exported to computer science to make easier to use what engineers designed with their logic that isn’t users friendly.
Taking into account the cognitive aspect of users allows to adapt the functionalities of software and applications to their capacities in a certain context of use.

Designing a good user experience means simplifying the use of applications according to who uses them, where and for what purpose. The same application will not offer the same experience to someone who is used to digital technology as to someone who is not very comfortable with it. The experience will not be the same if one uses an application alone at home or in a group outside.

Organizational ergonomics

Organizational ergonomics is the study of complex systems, communications and group management.

Its roots are linked to the military world. During complex vehicle maneuvers, soldiers hesitated between responding to the orders of their commander or the vehicle expert. The commander and the technical expert could give contradictory orders and lead to failures related to the formal and informal internal organization.

This form of ergonomics is easily associated with product design. Organizing inter and intra-team communications well within a company is essential to produce something (like a mobile app) on time and without stress.
In a way, this is what agile methods try to do by maximizing horizontal rather than vertical communication and by multiplying short meetings so that everyone can express themselves.

More directly related to the user experience, organizational usability is to be taken into account for the invisible part of an application, what actually happens when a user presses a button.

In the case of an online shopping application, validating an order means sending messages to different actors: delivery people, stores, after-sales service, etc. The messages must be sent, read and understood by every party involved, and the user must be given the possibility of tracking his order.

If the communication between all the actors of a service is not coordinated, there is a risk of impacting the overall user experience, not due to the interface but due to customer satisfaction.

Thinking beyond the graphical aspect of an interface and taking into account the physical, cognitive and organizational implications of using an application allows us to go one step further in designing optimal user experiences. The activity should be thought of as a whole, not as a series of isolated actions.