When Focusing on Behavior Isn’t Enough

Cognitive Reasoning Behind Human Factors for Medical Devices

When Focusing on Behavior Isn’t Enough

Cognitive Reasoning Behind Human Factors for Medical Devices

Ergonomics is the study of how humans behave in relation to medical devices. Through the gathering of research and scientific evidence, usability testing is conducted based on the behavior of the end-user. While this is an important aspect of Human Factors Engineering, it lacks one important consideration- the cognitive functions that humans will bring to the device. In other words, just as important as studying what the end users are doing, is learning why they are doing it.

In order to better design a user-friendly device, Human Factors Engineers can look at patterns, not only in human behavior, but human cognition. The following are a few suggestions made based off proven psychological principles in order to best eliminate potential human error.

Make it Intuitive

Shape, texture, size, and other physical characteristics can imply how medical devices are supposed to be used. These “affordances” are an important communication tool to limit misuse and ensure the intuitively of the device.

Some every day examples of affordances include pushing button, turning knobs, pulling handles, or sliding levers. The same is true with medical devices. People are familiar with certain grips to twist, handles to lift, or buttons to push. When designing a medical device, it is important to make actions intuitive by following previously made notions.


Have you ever seen a long list and automatically remembered only the beginning and end? This is a common phenomenon, called the “primacy and recency effects.” People retain items in the beginning and end of the list more than the middle of it. Because of this pattern, it is important to prioritize what needs to be remembered, and organized accordingly. From warnings to directions, think carefully about where you put vital information.

Keep it Simple

On average, working memory capacity is about “7 items at a time”. Making people rely on their memory isn’t only impractical it can be dangerous. Complicated medical devices with many options and steps are more likely to encounter human error. When possible keep it simple. Limit the complexity, as not to distract from other tasks.

When it is necessary to include multiple steps in device use, “recognition beats recall”.  Set up recognizable icons or reminders to prompt users what to do, and where to go next. The engineers use of layout to simplify the process and use reminders over working memory wherever possible can considerably lower the chance of user errors.


We will never be able to fully predict human behavior, so it is important to continuously test and study human factors when it comes to medical devices. Meeting with peers and industry leaders is one way to stay up to date with best practices. Q1 Production’s Medical Device Human Factors & Usability Conference is a chance for human factors engineers to discuss challenges including navigating the newly established regulatory landscape around the industry, while also improving the usability of medical devices, usability studies, and avenues to incorporate testing earlier into the product development process.