Interfaces that vibrate soon after we click a virtual button (on the order of tens of milliseconds) and whose vibrations have short durations are preferred. This combination simulates a button with a “light touch” – one that depresses right after we touch it and offers little resistance.

Users also liked virtual buttons that vibrated after a longer delay and then for a longer subsequent duration. These buttons behaved like ones that require more force to depress.

This is very interesting. When we think of multimodal feedback needing to make cognitive sense, synchronization first comes to mind. But there are many more synesthesias in our experience that can only be uncovered through careful reflection. To make an interface feel real, we must first examine reality.

“You’d swear you could touch the terrain,” HiRISE operations manager Eric Eliason said.

Alas.

In October 1946, philosopher Karl Popper arrived at Cambridge to lecture at a seminar hosted by his legendary colleague Ludwig Wittgenstein. It did not go well: the men began arguing, and eventually, Wittgenstein began waving a fire poker toward Popper. It lasted scarcely 10 minutes, yet the debate has turned into perhaps modern philosophy’s most contentious encounter, largely because none of the eyewitnesses could agree on what happened. Did Wittgenstein physically threaten Popper with the poker? Did Popper lie about it afterward?

The authors provide a comprehensive biographical and historical context for the incident, and use it as a springboard into the two men’s respective philosophies. It’s an enjoyable look at two self-important, short-tempered intellectuals and their rivalry.

As I mentioned in this post, I find Wittgenstein’s philosophy of language often invokes touch themes. In the following excerpt from Poker (originating from one of his lectures), Wittgenstein makes a point about a colleague’s statement, “Good is what is right to admire,” utilizing a haptic metaphor:

The definition throws no light. There are three concepts, all of them vague. Imagine three solid pieces of stone. You pick them up, fit them together and you now get a ball. What you’ve now got tells you something about the three shapes. Now consider you have three balls of soft mud or putty. Now you put the three together and mold out of them a ball. Ewing makes a soft ball out of three pieces of mud. (68)

Another example stems from Wittgenstein’s midlife change in philosophical outlook. In his first publication, the Tractatus Logicio-Philosophicus, he was preoccupied with the “picture theory of language”—the idea that sentences describe “states of affairs” that can be likened to the contents of a picture. Later, he developed a theory of language based on words as tools for conveying meaning. In my reading, he shifted from a vision-based to a haptic-based (in fact, a distinctly physical-interaction-based) understanding of how language works.

The metaphor of language as a picture is replaced by the metaphor of language as a tool. If we want to know the meaning of a term, we should not ask what it stands for: we should instead examine how it is actually used. If we do so, we will soon recognize that there is no underlying single structure. Some words, which at first glance look as if they perform similar functions, actually operate to distinct sets of rules. (229)

Here’s the relevant passage directly from Philisophical Investigations:

It is like looking into the cabin of a locomotive. We see handles all looking more or less alike. (Naturally, since they are all supposed to be handled.) But one is the handle of a crank which can be moved continuously (it regulates the opening of a valve); another is the handle of a switch, which has only two effective positions, it is either off or on; a third is the handle of a brake-lever, the harder one pulls on it, the harder it brakes; a fourth, the handle of the pump: it has an effect only so long as it is moved to and fro. (PI, I, par. 12)

Words as the physical interface to meaning. Love it!