Pictures can have literal, metaphorical, or conventional meaning.
At the literal level, the picture designates what it represents—
what you see is what you get. At a metaphorical level, it means
something akin to what it represents. At the conventional level,
it basically signifies whatever the convention decides that it will,
just like a new entry in a dictionary: you have to know the code.
Needless to say, a more literal representation is more intuitive.
Also, the fact a picture can be interpreted more or less literally
can confuse viewers, who may not know which level is intended.
This picture, taken in a light-rail station in Seattle, exemplifies
some of the issues with a picture's “literalness” (or lack thereof).
First, the drawings are metaphorical at best: you do not expect
handheld camcorders and table microphones on the platforms.
A single drawing of a surveillance camera would be more literal,
hence more intuitive. Second, the blue circles are conventional.
What are they supposed to mean here? For the European I am,
and as per the Vienna convention of 1967 governing road signs,
a blue circle indicates a mandatory action. Must I thus interpret
the right sign as meaning “you must use the table microphone“?
This would admittedly be a subjective interpretation (how I hate
when the lecture room does not provide a clip-on microphone),
but subjective interpretation is really what pictures are all about.
One good point about the sign: it clarifies the intended meaning
with a concise text statement, as a form of effective redundancy.
It even motivates what may be seen as an unpleasant constraint
(big brother is watching you) by placing motivation before action.
Still, is this a correct usage of the adverb audibly? Does it mean
that they are not recording any infra- or ultrasound, perhaps? ;–)
Tue 5 Apr 2010
Don Sheehy made the following observation:
You may not have noticed that there is another metaphorical level
at which this sign reads, which communicates subconsciously
to those who don't bother to read it or even look very closely.
It is a face with two large eyes. It says, “The walls are spying on you.”