Product design is a broad term for designing items for an end-user. In my own experience, there are different types: the type that I know and love so well – non-digital physical items, and then there are digital spaces like software or the product that holds digital space itself, like smartphones. 

Technology is ever-changing – and realistically, the everyday products we use are digital ones – smartphones, laptops, tablets, etc. This is why I’ve come to understand that “product design” is increasingly referring to the digital realm. But should the term mostly refer to digitally applied design? Absolutely not – while the most common focus of UX is for digital, design is design is design. These thoughts aside, the focus here is designing for digital spaces.

Mental models are the users’ assumptions on how something should work. Behind a screen, audience members use their mental models with how they think an interface should look and function based on past experiences with similar products. However, they’re also subject to change if the feature at hand is not an unwritten necessity, like using a light interface versus a dark one. There are some features, though, that may confuse users – like if a store’s website navigation menu were not towards the top of the page. If a user can’t easily find how to get where they want to go, they’ll likely not waste much time trying to find out – which may affect the store’s sales. 

This is why mental models are an important concept when designing for interaction. Deeply thinking about mental models should happen at the beginning of the process, as it will be like a backbone for usability.

In contrast, iterative design can be used during any stage of product development. Iterative design is essentially prototyping, testing, analyzing, and refining. The idea for the best turn-out is to fail early – so ideally, this part happens before launch, but it can also help refine a product afterward. The sooner you design something that doesn’t work how you’d thought, the better – because then it can be improved for potentially the best outcome. 

Personally, I couldn’t help but compare the principles behind designing for digital to designing for analog physical items. When thinking about mental models, I began realizing how anyone could use a dish towel – where it sits in the kitchen, how often it gets used, etc. – and how the design of a simple dish towel could change (or not) based on these models. 

Then, iterative design is essential, but I think it often gets forgotten more with physical items (more so the ones that have already been designed, like dish towels) rather than digital spaces. Here’s why: results aren’t as easily measurable as this doesn’t involve click rates or time spent on a page. Also, long testing processes with focus groups and interviews may not be as feasible without measurable actions, and while most launch timelines are quick. This is why these designers focus on the market research, trends, and personas to back up their product – but I think they can often forget that collaboration and feedback in many ways can substitute measurable actions. 

Alternatively, iterative design for physical items that are new and innovative isn’t frequently forgotten. This is because there are fewer – if any – market research products that help sustain design feasibility for the user without testing. 

Ultimately, mental models and iterative design go hand-in-hand and are equally important for the design of a product. Maybe the first prototype failed because the designers’ perceived mental model of the user was incorrect, and that’s when analyzing and refining comes in for a repeated process. Both at that time would be modified with the ultimate purpose of launching a great product for the end-user. 

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Baxter, K., & Courage, C. (2005). Understanding Your Users A Practical Guide to User Research Methods, Tools, and Techniques. San Francisco, CA: Elsevier Science & Technology.

Design iteration brings powerful results. so, do it again designer! The Interaction Design Foundation. (2021, January 1). Retrieved January 30, 2022, from https://www.interaction-design.org/literature/article/design-iteration-brings-powerful-results-so-do-it-again-designer 

Nielsen, J. (2010, October 17). Mental Models and User Experience Design. Nielsen Norman Group. https://www.nngroup.com/articles/mental-models/