My two year old daughter happily uses my iPhone every day. She quickly navigates to her favourite games, and loves to flick through our family photos.
Last night she was watching me browsing through some photos on my laptop, which she knows is off limits. Apparently I wasn’t browsing through the photos fast enough for Matilda. She quickly put her finger to the screen and dragged it to the left to try to slide to the next pic. Yes, there was a bit of a tanty when she got frustrated that it wasn’t working the same way it works on my phone.
For someone who’s never used a mouse or a touchpad before but is comfortable with the iPhone, using her finger to interact with the screen is a really logical way to interact with the new technology. Matilda’s expectation was that her finger would enable her to interact with the screen, just like it does on the iPhone. As designers, I know we try to think about what the user already knows and what their expectations are, and then try to build upon that. Seeing Matilda trying to drag the laptop screen with her finger reminded me how important it is to consider the Principle of Least Astonishment in design. Users build expectations really quickly, so it’s critical that designs are consistent to minimise the number of surprises for the user.
If you feel surprised or astonished when interacting with technology, it’s generally because the experience is a departure from your expectations. We can apply this to experience design in the offline world too. I was recently astonished by my energy provider who were unable to generate a bill for me for more than 6 months, despite my repeated requests for an invoice. This was a huge departure from my expectations, which were based on previous experiences with services from energy providers. Naturally it left me astonished, surprised and disappointed with the experience.
Here are a few quick and easy ways we can address the principle of least astonishment in UI design:
- Grouping like objects together
- Placing the same buttons in the same location across different screens
- Using the same labelling and terminology in content
- Using colour consistently throughout a design