Source: Information Visualization, Perception for design,Collin Ware Sensory and Arbitrary symbols
- There are sensory symbols, that derive their expressive power from the ability to use perceptual processing of the brain without learning, and arbitrary symbols, that must be learned because the representation has no perceptual basis. (ie. the word dog)
- Sensory representations are effective because they’re matched to early stages of neural processing. (ie cave paintings still giving it’s meaning thousands of years later).Arbitrary conventions derive their power from culture, and therefore are dependent on it.
- Properties of sensory representations:
- Understanding without training: the meaning is perceived without additional training
- Resistance to instructional bias: visual illusions persists because they’re hardwired in our brains, so they’re resistant, bottom-line facts.
- Sensory immediacy: information is neurally processed in parallel, this processing is hardwired and fast, so that we can separate information in segments, segmentation (ie. texture below)
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- Cross-cultural validity: will be understood across cultural boundaries. When not, its most likely because a sensory code has been arbitrarily dictated to be used against it’s natural interpretation.
- Characteristics of arbitrary codes
- Hard to learn: It takes many hours to learn to read and write even if we already know to speak.
- Easy to forget: In contrast, sensory can never be forgotten. If we overlearn an arbitrary code (ie numbers), the code will never be forgotten.
- Embedded in culture and applications: Color meaning is mostly culture-specific. Some arbitrary representations can be nearly universal, and many time has been invested in them, becoming standardized. That means that even if new, more sensory representations where developed, the effort would be in vain. Note: This reminds me of how all over the world we use the QWERTY keyboard layout and have spent a great deal of time teaching-learning it, and it has become the standard, even though the DVORAK keyboard layout has been identified of being faster to type,intuitive, and ergonomic (I have tested it) . For those that don’t remember, in the old times of mechanical typewriters, the keys got stuck if you became a fast typer, so many sources dispute that QWERTY was designed to slow down typing, and maybe there is a little bit of truth in that.
- Formally powerful: Arbitrary mathematical constructs can convey a lot of power to express concepts. That doesn’t make it easier to learn.
- Capable of rapid change: our visual systems have evolved to understand sensory codes, but that took millions of years. Arbitrary codes appear faster, and in this time computers aid in their invention.







