What is Human Factors Psychology?
I get this question nearly on the daily, not even joking. So you'd think my elevator pitch would roll off the tongue without me even having to put in a thought, well it doesn't. The reason I don't have a scripted response is that whenever I try to answer this question, I make an attempt to relate the field to something the person knows a lot about. This is because it really does apply to nearly everything, at least everything that involves humans.
According to the Human Factors and Ergonomics Society (HFES, 2000), Human Factors is defined as: Ergonomics (or human factors) is the scientific discipline concerned with the understanding of interactions among humans and other elements of a system, and the profession that applies theory, principles, data, and other methods to design in order to optimize human well-being and overall system performance.
For a pilot: I might say, well the entire field of aviation safety is related to Human Factors. Human Factors research is how we determine the minimum rest cycle an aviator can have before going to fly, or where to place and how to label switches in the cockpit to ensure intuitive flow and avoid errors. Have you ever wondered how it was determined that airline flights require pressurized cabins? How do we determine the number of negative G-forces the average person can take before they redout? That's Human Factors research in action.
For a software developer: I can first bring up the field of User Experience or UX. This usually gets them on track quick. User Experience is simply a more focused type of Human Factors. How do we ensure that user will know what to do next in the system? What is the right amount of intuitive design versus required user training? We often have to make tradeoffs for how easily we want a person to be able to understand the information they are receiving at the cost of how much information we can deliver.
For a high school teacher: I might ask them how often they give tests to their students? Follow that up with how do they know that the test is actually measuring their depth of knowledge? Then ask the really controversial question of whether or not they think homework improves knowledge retention. Work by Cooper et al. (2006) found correlations between homework completion and achievement in older students (Grades 7th-12th). However as the saying goes, correlation does not equal causation. Observational research is considered amongst the weakest forms of studies in scientific communities, paling in comparison to robust controlled experimental methods. In this instance, students who had greater achievement could simply be doing the homework because they are focused on achieving, this does not necessarily mean that the homework contributed to their achievement in any way.
For a fast-food service worker: I would ask them how often they get an angry customer who wants a refund? What percentage of time is that customer a repeat complainer? Why do you think they keep coming back if they are unhappy with the service? In fast-food service, the staff often see the same customers coming back shouting at them that their order is all wrong. The manager promptly refunds their money and replaces the food order. This reinforces the behavior, thus leading to the customer complaining again. Thus the customer has built a mental model and developed a system of how to get cheap or free food. The habitual complainers tend to cycle through the establishment every few weeks, when they feel that enough time has passed that the staff have forgotten the interaction. Well, I have news for you, they remember exactly who you are and how you treated them.
Point being, if humans are involved, I can easily find a Human Factors application. As esoteric as the terminology seems, it's perhaps one of the most commonly understood concepts among people, they just never knew how to label. Now you do!
Cooper, H., Robinson, J. C., & Patall, E. A. (2006). Does Homework Improve Academic Achievement? A Synthesis of Research, 1987–2003. Review of Educational Research, 76(1), 1–62. https://doi.org/10.3102/00346543076001001