After stumbling on a webpage that rants about the fallacy of "picture under glass", I began to wonder what was it that made multi-touch interfaces seemingly become so natural to all of us today?

We have been interacting with GUIs for so many years and the multi-touch interface, which is a new interface, should appear to us as unintuitive, or at least illogically unintuitive. For example, squeezing with 2 fingers on a screen to resize a picture isn't natural at all because other than the plasticine I used to play with as a kid that could allow me to manipulate its size by squeezing, there are few things in the physical world for me to relate this action to. I wouldn't have thought of this squeeze "gesture" if I hadn't been told about it.

How did all of us just begin to find such multi-touch interfaces natural?

  • 3
    Touching things to interact directly with them is about as intuitive as one can get.
    – DA01
    Feb 5, 2012 at 22:36

6 Answers 6


A main component of natural interactions is Direct Manipulation. Traditional interaction methods (keyboard) are very efficient but often very unnatural because what you do and what happens on screen aren't necessarily very logically connected. This was a classic problem with command line interfaces (or worse, punch cards). The Graphical User Interface was largely a hit because of the Direct Manipulation it affords. As a bit of trivia, Video Games, especially Pong, quickly showed the ease of control direct manipulation can give people.

With touch interfaces you directly touch what you want to interact with, making buttons extremely natural. Panning and zooming might not occur exactly as they do with real world objects, but they operate exactly and move fluidly due to your manipulation. Move your finger 10 cm in a pan gesture and the screen scrolls 10 cm with your finger.

It's been shown repeatedly that users love Direct Manipulation. It creates an effective, engaging interface and allows the user to feel in control. Even if the exact action (like panning) isn't 100% intuitive, it is extremely easy to learn. The causality is very clear, leading to very few "wait, what did I press?" moments.


I think it has nothing to do with plasticine :). Hold up your hand and show "a small amount of something". You're probably pinching. "A pinch of salt" is a small amount of salt. I assure you that both the gesture and the expression have existed long before multi-touch :). Ask a person to demonstrate something large, and he will spread his hands. Ask him to demonstrate something growing smaller in size, and he will bring them closer together. If he needs to only use one hand, he'll do a pinching motion. Ask him to show something growing larger and he'll start from a pinch and spread his fingers or arms. The concept exists in our minds and we demonstrate it using our limbs.

Intuitive interfaces correspond first and foremost to mental concepts, while interfaces which only correspond to the way we operate on physical objects are less intuitive.

  • Agreed, people will tend to give a consistent answer if you ask them to show something getting bigger or smaller. They may learn this as babies from interaction with real objects.
    – PhillipW
    Feb 6, 2012 at 9:51
  • @PhillipW That's the thing, I don't think learning from real objects has anything to do with it. The concept of "size" exists in our minds, and we use our hands to illustrate concepts. So if we show a transition from "large" to "small", we end up with pinching, regardless of whether we've encountered objects which actually change their size. Feb 6, 2012 at 12:14

Multi-touch interfaces are no more 'natural' (the term itself is misleading, or at least poorly defined) in the context of interfaces. A keyboard is 'unnatural' but a far more effective input device for text than a touchscreenl. The difference is that the technology to make a multi-touch screen (and the portable computing device it sits on) has only recently been popularised and marketed - and as with many other interface types before, terms like 'natural' and 'intuitive' have been applied to help with marketing. Like any other technology, they are good for some problems, less good for others!

  • Multi-touch interfaces as applied today are certainly more natural to the alternatives. Certain interactions are simply more intuitive and natural feeling than others. And direct tactile manipulation is certainly more natural feeling than moving a mouse to push a cursor to manipulate an object, which in turn is more natural than using arrow keys to do the same thing. That has nothing to do with marketing. Feb 6, 2012 at 8:49
  • 1
    Unfortunately 'natural' is not a well-defined term (like "user friendly") so does not help in understanding interface technologies. While for some input-driven tasks (such as reading online) touchscreens are useful, whenever an output component is involved (manipulating an image, for instance by a graphic designer) touchscreens become less effective (not least because the extra physical effort leads to greater tiredness!) and the interactions more contrived. There are no technologies which are "better" or more "natural" in absolute terms - it all depends on the task and environment.
    – Peter
    Feb 6, 2012 at 11:13
  • "User-friendly" is more ambiguous than "natural". Words like "natural" and "intuitive" speak to a specific quality that might contribute to user-friendliness. How is that less helpful in understanding interfaces? Also, whether a touchscreen is universally the best interface for all purposes is besides the point. No one here has argued that. Though even for graphic design, a touch screen or tablet is preferable to keyboard or mouse. Anyone who has experience in digital painting or illustration will tell you this. Feb 6, 2012 at 11:26
  • I think we'll just have to agree to disagree on this one :)
    – Peter
    Feb 6, 2012 at 11:27
  • 1
    Keyboards are efficient and effective but require extensive training to master; they are not intuitive or especially discoverable at first use. Touch is much more intuitive and most effective for those tasks which do not require extremely efficient and specific input like text entry.
    – Ben Brocka
    Feb 6, 2012 at 15:59

I disagree that the post argues that the interfaces are particularly "unnatural" -- as far as I can tell, it is about the visions of interfaces reaching much less far than the author thinks they could.

All of the squeeze gestures I know of are based on a simple and (in my opinion) natural principle: if you touch a spot and move your finger, the spot moves along. This is true for dragging, rotating, and for both kinds of resizing (zooming in and zooming out). With a third finger, one could keep two fingers in place and then skew the image with the third. Alternatively, if the image was 3D, it could be a rotation. I just came up with these interpretations a minute ago, but they're not anything new; they're just a natural extension of the same principle.

What the article does say is that limiting everything to this one principle is very limiting. Nobody ever holds their phone in the scissor grip because it wouldn't be any use. What if phone designers created a use for that? The Wii was a step forward in this regard -- you could do all kinds of things with your body and control games that way.

To give a further example of what we could have with the current "vision" versus a more future-oriented vision: let's say you have a graph and you'd like to manipulate the nodes and edges. The current vision could give you a flat table with the graph projected on it and let you touch a node and move it, or touch the side of a node and drag a new edge to another node. Another vision could give you a pit of sand and let you places smooth stones on it for nodes and run lines through the sand for edges. If I understand the article correctly, that's the kind of difference it's looking at, and I have to agree the first is a little underwhelming.


I think the point here is that at some point or other everybody has played with 'squeezy' stuff like plasticine (even if it was a long time ago)

You only need to learn what happens when you stretch it once.

  • But the plasticine doesn't allow us to stretch its material with 2 fingers like how we could on multi-touch interfaces. The gesture is novel and is not natural.
    – xenon
    Feb 5, 2012 at 16:22
  • OK, maybe that stuff which you stick things on the wall with is a better example of a material which is stretchy.
    – PhillipW
    Feb 5, 2012 at 16:24
  • @xEnOn: One of the nice things about human learning as opposed to computer learning is that we're able to extrapolate and generalize knowledge with great facility. If we're burned by a lighter, we'll know to avoid other heat sources even though they don't look exactly like a lighter. Using 2 fingers to stretch something as opposed to 3 is just nitpicking. The principle action of the stretching only needs 2 moving points to demonstrate. This is something that even a toddler can pick up on. Feb 6, 2012 at 11:31

First of all, Plasticine isn't the only thing that kids stretch, elastic bands, inflatable boats, telescopic pointing devices and baking doe stretch too.

Second of all, you usually use two hand to stretch or rotate physical objects. You can use two hands with the same interface used on multitouch screens. This is not commonly done simply because, although it is easier to do with two hands, often the device is not placed on a table, but held in one hand, therefore, you are only left with one available hand with which you can operate the device.

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