[wingerlang]

> The time to acquire a target is a function of the distance to and size of the target.

If you need to move the cursor far and to a small target, it will take a long time to hone in on it.

The shorter you have to move it, and the larger the target - the easier it is to click.

For example the menu on macOS is always at the top of the screen, making its target HUGE and is therefore basically O(1) to hit.

[alxlaz]

What (I believe) gkya was trying to point out is that "the time to acquire a target is a function of the distance to and size of the target" is a rather pointless statement. Of course it's a function of the distance to and size of a target; but Fitts' law consists not in this observation (which was nothing new to Fitts himself, and most likely to the entire human race ever since the first Paleolithic man tried to throw a stone at something), but in the actual function, ID = log(2D/W).

The cargo-cult reading of Fitts' work which is so prevalent nowadays probably accounts for many of the instances of cargo-cult UX design that are so popular today.

[gkya]

I don't really know Fitts' work, but I do understand that what that sentence means is obviously "smaller things are harder to click or tap". But that is very obvious and thus meaningless without indicating what that implies: e.g. "make bigger buttons".

[alxlaz]

OK, first, that sentence does not mean "smaller things are harder to click or tap". That sentence would still hold true if smaller things were easier to click or tap. Besides, in 1954, when Fitts' paper appeared, it was already understood that this was the case.

I'm not being overly pedantic here -- Archimedes' principle is not that "whether an object sinks or floats depends on what it's made of", that had been known since the dawn of time. Archimedes' contribution was to give it a quantitative formulation, which is what we now call Archimedes' principle -- the force is equal to the weight of the volume of liquid that the immersed object displaces. Similarly, Fitts' law is not that larger targets are easier to hit, that has been understood forever; it's quantifying this statement, and the end result is what we now know as Fitts' law.

Second, the implication "make bigger buttons" is not at all valid in every circumstance -- which is why I warmly suggest reading the actual paper to anyone who cites it.

Fitts' work applies to repetitive movements of equal amplitude and speed, not necessarily made with active cognitive involvement, and assumes that targets are known in advance and -- although not explicitly stated, but implicit in the experiment -- easily distinguishable. It will tell you nothing useful about the size of buttons in dialog boxes, for example. (Edit:) this blind interpretation would also suggest, for example, that making the macOS menu thicker would help, but it doesn't; or that simply making buttons thin, but placing them on top of the screen, would also help -- which holds is only partially true for mouse-driven interfaces, and not at all for touch interfaces.

[gkya]

I'm not really interested in these details, and "make bigger buttons" was just an example of what an implication might have been (as indicated by "e.g."). What I tried to criticise was the vagueness of the linked page and the scarcity of information.

[alxlaz]

> What I tried to criticise was the vagueness of the linked page and the scarcity of information.

So if you are not interested in "these details", but you found the page vague and the information scarce, what details should it have included so as not to be vague?

[gkya]

> what details should it have included so as not to be vague?

- How is the correctness of such "law", expecially in context of UX desgin, is observed?

- What are practical implications of these "laws", again in the context of UX design.

[rmrfrmrf]

Or space them out more. Of course these concepts seem trivial when you implicitly shave off half the content and then fit it to your own pre-conceived solutions.

[rmrfrmrf]

I tried to upvote you, but hit the downvote button instead :(. Oh well.

[seanmcdirmid]

HN is not Fitts’ law compliant.

[gkya]

It's not that I don't understand this. It's that a web page on "the laws of UX" counts on the readers' interpretative capabilites to get such point across, and excludes any concrete example to make their point clear.

[elcapitan]

Unless you use a very large screen, in that case you often have to move the mouse over half the desk any time you want to click the menu. I remember the fun I had back when Apple produced those 30" screens.

[seanmcdirmid]

For touch that is true, for mouse and pen you still have to consider travel time.

[wingerlang]

That's the distance

[seanmcdirmid]

Yes (but for touch on a phone or tablet, being on the edge of the screen is better because your hands are already resting near there + occlusion sucks).