Should icons be based on what they do rather than the appearance of an object?

Question

A lot of icons or universal symbols are showing their age, such as the telephone handset, or the thermometer images I have seen in recent questions. What if instead of depicting a device, the icon depicts the activity? Telephone literally means "distant speech", and the aspect of humans talking is probably the invariant as time marches on. (A phone is already just a rectangle, like most other electronic devices.)

A liquid bulb thermometer is similarly outdated - where I live you can exchange one for an electronic one for free. Soon they will no longer exist except in museums. What should the icon for temperature be? People often use a snowflake for cold and fire for hot, but many people never see snow, so that is no better than the thermometer image. Fire is also non-existent in most situations now, except when camping, so it is not a good fit for modern life.

How can we come up with icons that actually show the invariant characteristics of things, instead of their implementation in technology? I think that will be a payoff over time, as I expect that literacy will drop off when people can simply converse with computers and no longer need to read and write at all. It really does not answer the question to sweep it under the rug. We are talking about design here, not economics. Try to design well, "As if for God and not for Man." (Colossians 3:23)

Here is a good example of this confusion from here on the UX.SE site: Origin of Database icon

Addition: Perhaps we should skip the icons for now and use words instead, since the presumption in using a computer is that you can read? Visual design is becoming simpler (Flat) and less cluttered, so a few words on the screen work as well as a few icons, and are more direct. Mostly people learn where to click and then stop paying attention to what they are clicking.

Answer 1

This is one of the main areas of interest in semiotics and as such, it's vastly covered, although there are 2 main theories from which posterior theories emerge. These theories have more than 100 years and are the theoretical support for modern design, starting from first wave of linguistics , then Bauhaus and coming to these days.

To make it short, these theories were created by Ferdinand de Saussure (dyadic sign model) and Charles Peirce (triadic relation theory):

There are two major theories about the way in which signs acquire the ability to transfer information; both theories understand the defining property of the sign as being a relation between a number of elements. In the tradition of semiotics developed by Ferdinand de Saussure the sign relation is dyadic, consisting only of a form of the sign (the signifier) and its meaning (the signified). Saussure saw this relation as being essentially arbitrary, motivated only by social convention. Saussure's theory has been particularly influential in the study of linguistic signs. The other major semiotic theory developed by C. S. Peirce defines the sign as a triadic relation as "something that stands for something, to someone in some capacity"1 This means that a sign is a relation between the sign vehicle (the specific physical form of the sign), a sign object (the aspect of the world that the sign carries meaning about) and an interpretant (the meaning of the sign as understood by an interpreter). According to Peirce signs can be divided by the type of relation that holds the sign relation together as either icons, indices or symbols. Icons are those signs that signify by means of similarity between sign vehicle and sign object (e.g. a portrait, or a map), indices are those that signify by means of a direct relation of contiguity or causality between sign vehicle and sign object (e.g. a symptom), and symbols are those that signify through a law or arbitrary social convention.

While both theories cover your specific question, the triadic relations model relates to it in a more direct manner. See below the description or classes of triadic signs:

1. by what stands as the sign — either (qualisign, also called a tone) a quality — or (sinsign, also called token) an individual fact — or (legisign, also called type) a rule, a habit;
2. by how the sign stands for its object — either (icon) by its own quality, such that it resembles the object, regardless of factual connection and of interpretive rule of reference — or (index) by factual connection to its object, regardless of resemblance and of interpretive rule of reference — or (symbol) by rule or habit of interpreted reference to its object, regardless of resemblance and of factual connection; and
3. by how the sign stands for its object to its interpretant — either (rheme, also called seme,such as a term) as regards quality or possibility, as if the sign were a qualisign, though it can be qualisign, sinsign, or legisign — or (dicisign, also called pheme, such as a proposition) as regards fact, as if the sign were an index, though it can be index or symbol — or (argument, also called delome) as regards rule or habit. This is the trichotomy of all signs as building blocks in an inference process.
   • Any qualisign is an icon. Sinsigns include some icons and some indices. Legisigns include some icons, some indices, and all symbols.
   • Any icon is a rheme. Indices (be they sinsigns or legisigns) include some rhemes and some dicisigns. Symbols include some rhemes, some dicisigns, and all arguments.

An easy example

Linguistics and specifically theory of signs is a very dense subject, so I'd understand if you didn't read the explanation above. So let me use a real life example:

We were building an sciences app for students covering different subjects, two of them being Hydrography and Oceanography. Being this for teens, it was clear any iconography used had to be extremely clear and simple, so we started using wavy lines to represent the significant for river, streams of water, and hydrography by association. It worked somehow, just not enough to consider it 100% effective (not even close). Regarding oceanography, we chose "sea like" waves and a version with a lighthouse as well. None of them worked as satisfactory as we would hope.

Then we tried a few more options until we came with a helm and a starfish for both concepts. Amazingly, they did the trick. While we are used to this kind of associations and a helm wasn't really far fetched, we were vey curious as to why they chose helm for river and a starfish for sea. The answers were in the line of "obviously a starfish is from sea" and "starfish is for sea, so helm has to be for river".

This is to illustrate how significants work in triadic models. The icon wasn't direct, most kids never saw a helm and probably they never saw a real starfish. Yet, the connection between significants (including context) was strong enough to provide the most accurate results. And the same happens with your examples: there's no need for a real connection between significant, signifier and interpretant , these connections are artificially created by context, culture, technology, reference groups and so on.

In short

A phone shape is not a phone, but the collection of signifiers the interpretant derives from that shape in a given context

Answer 2

I suggest you have a look at the article "Icon Classification: Resemblance, Reference, and Arbitrary Icons" by Jacob Nielsen.

According to Nielsen, there are three broad categories of icons: resemblance, reference and arbitrary icons.

His studies seem to suggest that:

Resemblance icons usually have the best usability, though an arbitrary icon can be great if it has already been widely standardized by the time you employ it in your design. Don’t be the one to try to teach the world a new arbitrary icon, though. You will likely fail.

Sometimes icons that start as resemblance icons later become reference icons. An example is the floppy disk as "Save" icon:

Originally, this was a resemblance icon: users actually saved their files on floppies, so as long as the icon looked reasonably like a floppy disk, it was likely to be recognized and understood. Later, people got hard drives and the “Save” icon became a reference icon.

In summary, at this point in history using a phone for a "phone" icon seems to be potentially a better idea that using a "distant speech" icon. But, as usual, only testing with users can give us insights about their mental model.

And by the way, that's one of the reasons why I design for people and not for God - they're a lot easier to invite to a user testing session ;)