An introduction to data and information
An introduction to data and information

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An introduction to data and information

3.2 Human beings, data, signs and symbols

We live in a sea of sensation: sight, sound, touch, taste, smell and balance (really a sense of our bodies in three-dimensional space). These sensations, and our ability mentally to process, and then react to and communicate them, are vital to our survival. What we perceive with our senses we call the most primitive form of data: perceptual data.

However, as Example 1 showed, human beings don't just react instinctively; they respond reflectively, using thought. In other words, we seek to name, to classify and finally to understand what we perceive. A reaction like withdrawing your hand from something that is painful to touch is instinctive. Physiologically, such a reaction protects us from harm.

Language, one of the defining characteristics of human beings, is a hugely complex system of meaningful sounds which can be combined and repeated. It enables us not only to name and classify our sensations, but also to communicate them and our thoughts about them to others.

About 30,000 years ago human beings began making ‘useless’ objects: items not strictly necessary for survival. They couldn't be used as tools, eaten or used to keep warm. They were the beginnings of art. These ‘art’ objects were often marked with regular scratches, rhythmic lines or dots. No one now knows what these marks meant to the people who made them. Yet we believe that they were signs conveying specific meanings to those who made and used them (anything from counts of days between full moons to reminders of important events in the stories told around the communal fire at night).

A sign (or symbol: we consider these terms to have the same meaning in this course) can be defined as something that conveys some information by means other than direct representation. Signs represent something other than themselves: they symbolise something. Signs vary: a beeping sound at a light-controlled pedestrian crossing symbolises that it's safe to cross while the beeping continues, an arrow on a traffic sign symbolises the way to go when it's not obvious (In this course the terms ‘sign’ and ‘symbol’ are considered to have the same meaning). In the well-known painting, the Arnolfini Double Portrait by Jan van Eyck (shown in Figure 1), the inclusion of the dog in the foreground symbolises domestic fidelity, and the convex mirror in the background symbolises the observing eye of God, keeping watch over the couple.

Figure 1 The Arnolfini Double Portrait by Jan van Eyck (1434) portrays the marriage of Giovanni Arnolfini and Giovanna Cenami, and is rich in Christian symbolism (National Gallery)

The painting includes many other objects which are symbolic as well as representational, such as the shoes, the single candle in the candelabra, and the positions of the couple's hands.

Generally, we distinguish signs and symbols from representations by saying that:

  • they have a meaning apart from their direct representation;

  • this meaning is understood by a group of people who agree broadly on what that meaning is.

A flag symbolises a nation or other group, and what is pictured on the flag usually symbolises things important to that group: homeland, language, history or myth. The hands of the couple in Figure 1 symbolise a very ancient custom that the groom ‘asks for the hand’ of his future wife, and the bride ‘gives her hand in marriage’.

Coming back to language, words are also signs. The word ‘cow’ symbolises a particular type of ruminant animal from which we get milk, meat, and sometimes muscle power. The word itself is not a cow; neither is it a particular cow (‘Daisy’); it symbolises the animal we think of as a cow.

Figure 2 From a map by Olaus Magnus, Swedish cartographer, 1539

Exercise 6

Would you call the item shown in Figure 2, and which appears on antique maps, a sign in the sense used above? If so, what does it symbolise?


It is intended to be a sign that symbolises a coniferous forest on the map (you may have said woods, trees or something similar). Note that most maps have a legend which explains the exact meaning of such signs, although they are intended to be easy to interpret.

Signs can be of many types. There are visual signs (such as road signs), audible signs (beeps and tones used as attention-getters or warnings) and tactile signs (such as textured paving stones near a road crossing).

Exercise 7

Can you think of any other examples of tactile signs? What might their uses be?


You might have thought of braille, which is intended to be read by those with a visual impairment using the tips of the fingers.

Even for sighted users, tactile signs can be useful. Where the user must use sight or hearing for other things (operating complex machinery), or where vision or hearing is not possible (in very dark or very noisy environments), the position, shape, size or texture of a tactile sign can ensure that the user knows what it is without having to look at it. Most cars, for example, use position to differentiate between two otherwise similar controls such as the indicator lever and the windscreen wiper lever.

An alphabet of touch

Louis Braille, the inventor of the braille system, was only a precocious 10-year-old when he entered Valentin Haüy's pioneering school for children with a visual impairment in 1819. Haüy – a specialist in decoding manuscripts before he founded the school – had already invented a form of writing for people with a visual impairment using an embossed alphabet. Though a great step forward, Haüy's system had its drawbacks: it was prone to errors and confusion.

When Braille was 12, Charles Barbier de la Serre, a French army captain, visited the school and described his system of 12 raised dots representing sounds which could be combined to form words. Braille experimented with Barbier's system and, by the time he was 20, he had simplified it so that each letter of the alphabet could be represented by six raised dots arranged in three rows.

The dots are precisely placed in relation to each other for each character and precisely aligned (sloppily written braille is even harder to read than messy handwriting), and the 63 combinations of dots and positions comprise an alphabet, numerals, the main mathematical signs and a music notation.

Braille is interesting because the basic unit of the sign is, simply, the raised dot, whereas most alphabets compose letters using straight lines, dots, curves and compound marks. Thus braille is very simple and purely abstract (that is, it has no remnants of an iconic system, such as representing the quantity zero by an empty circle). An average braille reader can read about 150 words a minute.

The braille system also freed those with a visual impairment to write for themselves (using a variety of hand- and machine-operated tools). Nowadays computers can produce braille text directly.

In summary, a sign or symbol is a way of representing data. For example, the word ‘blue’ is a sign of a particular colour sensation; a seemingly-simple word like ‘cow’ is a sign of a complex thought or idea derived from many sensations; a road sign can represent some condition of the road (e.g. that it narrows ahead) and warn the driver to take care.


Describe in your own words what is meant by a sign or symbol, and explain how your personal name is an example.


You might have said something like this: a sign is a representation of something, where the representation could be a sound (such as a word) or a drawing or some other more abstract representation. To be a meaningful sign, there must be a group of people who agree on what the sign represents.

My name is a sign in that it is not me, but represents me to myself and to others (e.g. my family, my employers, my community).


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