Look at your keyboard. What is it about the keys that make you know they’re clickable? Are they a different color than the rest of the board? Sometimes they are, but a lot of the times they aren’t. Now look at the nearest door. How do you know that its handle is the part you’re supposed to interact with? Is there only one differentiating characteristic that tells you to grab the handle and not the door, or more? Now look at a picture or poster hanging on the wall. There’s nothing that tells you to interact with it beyond just staring, is there? Why is that?
Over hundreds of thousands of years of evolution, the human eye has developed visual sensory receptors to help us navigate and interact with the world around us, the two main categories being cones and rods, counting at 6 million and 120 million, respectively. Cones provide the eye’s color sensitivity. They are less sensitive to light, but are responsible for all high resolution vision. The rods, more numerous and much more sensitive than the cones, are the cells we employ in low-light conditions, so sensitive that they can be triggered by single photons. They’re responsible for dark-adapting vision. All in all, there are roughly 126 million receptors in our eyes dedicated solely to differentiating the most minute of wavelength variations. What’s my point?
Mostly everything humans do in the world is dictated by our vision. Whether it’s grab, click, pull, push, swing, slide, etc, it’s usually our eyes that detect whether a given object is to be interacted with. But what do our eyes pick up on? It’s not just color, because many of us have been in all-white laboratories and have been more than capable of identifying the tables, walls, and doors. It’s because our eyes know we’re in a 3D world. We can detect light sources, and degrees of shading, and depth. And without any of these, we’d be absolutely lost.
And that’s how I feel when I use UI’s channelling the spirit of Metro. The Metro aesthetic is one based on completely stripping interfaces of all visual cues that our eyes have evolved to utilize in helping us to interact with our surroundings. These cues are called affordances and they’re traits and qualities of a given object that help us identify what it is we can do with it. Take one look at the Metro UI and you’ll notice the uncomfortable lack of shadows, highlights, and all-around spatial awareness. Can you immediately tell what you can and cannot interact with? Can I click on all those tiles? Are they all apps? Is that just a pinned photo, or an application? And to add to the confusion, why are there different sized tiles? There’s no surprise why you end up feeling as if you’re staring at a screen full of advertisements with the Metro look – we’ve come to expect billboards/photos/posters/ads to be nothing more than 2D objects that offer little cues for interaction beyond acknowledging their existence and the information they contain. I commend Microsoft for experimenting, but this is one path I just don’t understand going down, especially for a much anticipated, engine-restarting product.
If we have all the built-in tools to help us easily function in our surroundings, then it only makes sense for designers to utilize and exploit these tools when building their interfaces. And I’m not talking about making sure we include leather-textured navigation bars in our apps, but rather that we treat whatever concepts we’ve applied to our designs the same way we would perceive their real-world counterparts. I’m of the opinion that there should be a seamless transition between our analog and digital worlds. A clickable, tappable item should carry the same visual cues whether molded out of plastic or pixels. A button can be clicked because we know it can be clicked, and we know it can be clicked because we’re spatially aware of it, and we’re spatially aware of it because of the millions of receptors in our eyes, and we’ve got millions of receptors in our eyes because they work extraordinarily well in facilitating our every movement.
We’re already at a disadvantage using interfaces on flat touch-screens that effectively neglect our touch receptors, so what reason is there to blunt the very perceptive ability that guides most of our interactive decisions? We’ve been interacting with our environment for ages. Our visual ability works. It’s fine-tuned and of an incredibly high resolution, and optimized for human function. It only makes sense that good digital design play to that ability.
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