"Your brain is able to predict that if you don't see it, it might very well be rollover-only."
This statement is so wrong I don't even know how to react to it or steer you away from this sort of thinking. I'm just completely taken aback. Not trying to be argumentative or anything, but no no no no no. No, the user is not going to intuit that the function must be invisible because he can't see it. Arg.
Here is the proof. Usability testing.
the user is not going to intuit that the function
must be invisible because he can't see it
If every user interface with mouse input used a "hover the cursor to the right of the screen for edit/action buttons" pattern, it'd become quite natural to users.
Gnome 3 is a good example of where hidden elements are used successfully. Hovering the mouse in the top left "Activities" corner of the screen will show hidden content. The bottom right corner of the screen also shows hidden content (this time, without any visual affordance). Users learn to expect the hidden items to appear when hovering the cursor. No affordance is required. The downside is that users may not be able to discover this behaviour without help from a tutorial or manual (at least until "hot corners" become a standard UI pattern).
With web pages and apps, it's up to each designer to decide where and how things are laid out, and everyone has their own opinion, so if 20 designers decide to hide their components, how is the user to find them? The last thing I want to do is play hide-and-seek moving the mouse around a webpage/app randomly in the forlorn hope that maybe one of the gadgets or magic locations will pop up a control that I can use.
Put in a gear icon that I can mouse over. Put SOMETHING there that says "hey! I can be interacted with!" Otherwise I'll just ascribe the interface as designed by someone incompetent and look for an alternative.
I misinterpreted your "What is the affordance of invisibility?" question as in "what are the benefits of invisibility?". Thanks for clarifying. I didn't know (and couldn't find) that specific definition of affordance. Is it a technical term?
Just seeing the interface component intrinsically describes its use. This is not possible for invisible components, therefore they have no affordance at all.
It's true. But this isn't very relevant to this article is it? we're talking about hidden items, not invisible items.
"Your brain is able to predict that if you don't see it, it might very well be rollover-only." This statement is so wrong I don't even know how to react to it or steer you away from this sort of thinking. I'm just completely taken aback. Not trying to be argumentative or anything, but no no no no no. No, the user is not going to intuit that the function must be invisible because he can't see it. Arg.
You can be argumentative by showing some reasoning to your opinion. That would help. What is wrong with my statement in your perspective? Either way maybe I can clarify further. I don't think intuition and experience (prediction) are separated. I strongly believe in Jeff Hawkin's theory [1]. All we do is this: we learn things, and later, based on what we learned, we make predictions, and act based on those predictions. And I think this is very relevant with interface design. If a certain pattern becomes frequent, people will become familiar with that pattern, and that pattern will become more usable. The drawback to that is that some patterns may be crappy, but it's still something I take into consideration in making interfaces, consciously or not. Of course you can try to ignore all that and think completely outside of the box - I've tried it a few times and while it's a lot of fun, a lot of people get disoriented for longer, even though the concepts are simple. Think about how fast the learning curve in a simple 2D platform game is. Their rules are quite alien to our real world (super high jumps without dying, hitting bricks throws a mushroom, etc etc) but what makes that learning curve really fast is that we've learned it again and again. It wasn't easy the first time, but 2D platform are a familiar pattern; my generation has learned it since early age, with Mario and Sonic. Intuitive is, in a way, anything that feels familiar. And a familiar pattern in github is hidden functionality that appears with a rollover. If I don't see something, I can guess that it may show up when I so a rollover.
Here is the proof. Usability testing.
How does usability testing prove that "the user is not going to intuit that the function must be invisible because he can't see it"? Can you elaborate? Have you done the testing or have you read about it being statistically proven otherwise?
[1] http://www.ted.com/talks/jeff_hawkins_on_how_brain_science_w... (to be clear I'm alluding to the part about prediction)
Yes, usability testing confirms this, which is why you do it. Put key functions in hidden controls and then ask people to perform tasks that require discovering the controls. Most won't find them. In another comment here I mention my experiences with usability testing and finding that the much more well known paradigm of context menus is used or thought of by extremely few users. Advanced users will use it a lot, especially after the first time they look for context menus and find they are there and robustly designed in a given app, but non-advanced users, which is the vast majority, will never look there. In working with customers, some find the existence of features in context menus only after many years of work with a given program. One absolutely can not depend on users to assume that needed functions can be found in invisible items.
I appreciate that it isn't too much of a shibboleth for you and that you could stick around, I'd be interested in knowing a little more about the literature you mentioned. Do they propose specific techniques to usability testing? Which one do you use? In my case it's watching friends/family/expo attendants interact with the app but I don't have much of a formulated technique, it's casual, but I'd be interested in knowing more (and in the process I may be convinced that I should actually read that literature).
One absolutely can not depend on users to assume that needed functions can be found in invisible items.
I don't think it's that simple. It depends on the context and on the target. On a professional tool targeted to software developers like github, and being a consistent pattern, then yes, I think you can depend on that. If on the other hand you use that pattern in a context where it's not frequently seen, and/or it's not a consistent pattern in your app, you probably shouldn't depend on it, no.