Although it is true, as has been explained above, that everybody
has temporary problems interacting with the environment, it should
be remembered that such problems are often permanent (from birth,
or following an accident or illness, for the rest of someone's life):
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Dimensional diversity: nobody denies that there are dimensional
differences between people: height, weight, width of shoulders,
length of the hands and feet, etc. And what these aspects have
in common is that they can be measured using quantitative values
in order to draw up anthropometrical population tables. Often,
with the aim of doing things well, such tables are used to design
products or spaces that have to be used by the whole population.
The problem is that if we only use the central values of the table
(the arithmetic mean) we will end up with products, services or
environments that can only be used by a small sector of the population.
This is because both the lowest and the highest values reflect real
characteristics of at least one person of the group; they are not
values which have been randomly placed there by the researcher and
therefore they should not be ignored. Thus, designs based on dimensional diversity should be suitable for both the largest and the smallest
people, and this can be achieved in four different ways:
1. A single design that is valid for everybody: for example, making
doorways wide enough for anyone to pass through them, regardless of
their body size, the fact that they are carrying something or that
they are in a wheelchair.
2. Designing a range of objects which covers all possibilities, for
example, in the sizes of clothes.
3. Designing a product that is adaptable to different dimensions,
for example, a chair whose height can be adjusted.
4. Designing an accessory that adapts itself to an original design,
for example, car seats for children.
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Perceptual diversity: except for blindness, perceptual problems
usually go unnoticed by most people and this often leads to unconscious
discrimination against the group in question.
The loss, to varying degrees, of sight, hearing, smell, taste or
touch leads to daily problems of interaction with the environment
and may create significant hazards:
-For people who wear glasses rainy days present a big problem as wet
lenses mean reduced vision.
-Reading the information about a specific bus or metro route may
require a great effort for people with poor vision.
-When we shout at someone to warn him/ her of some danger, we don't
stop to think that that person might be deaf.
-People who lose the sense of smell (due to old age, a cold or an
allergy) may not be aware of a gas leak until it is too late.
-The loss of the sense of taste may lead us to eat food that is unfit
for consumption.
When we have an altered sense of touch (due to illness, old age or
low temperatures) we run the risk of causing serious burns to the
skin or mouth. Thus, in addition to designing environments with perceptual
diversity in mind, it is essential to make the population aware of
such problems and encourage respect towards people who suffer one
or more of them.
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Motor diversity: in referring to people with
mobility problems we normally think of wheelchairs and crutches.
however, there is a large variety of motor problems which go unnoticed:
-People who walk slowly need longer to cross the road at traffic
lights.
-People who have problems lifting their legs find it very difficult
to climb stairs or get onto a bus that does not have a low floor.
-If we have mobility problems in our arms we may not be able to use
a switch that is situated at a certain height.
-Those who have difficulty in moving their neck may be prevented
from looking up or at the ground.
-People who find bending difficult may not be able to tie their
shoes or use a public telephone that is not at their height.
-Problems with manual skills may prevent or hinder the handling of
small objects.
-Left-handed people have difficulties using tools designed only for
right-handed people.
Therefore, although 'environments for all' should be designed with
wheelchair users or people on crutches in mind, it should also be
remembered that there are other less visible mobility problems which
are equally problematic when it comes to interacting with the environment.
Designs that are not well thought out may favour one group to the
detriment of another: for example, escalators are fine for some people
with mobility problems in their legs but are inaccessible to wheelchair
users.
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Cognitive diversity: cognitive changes may affect our
ability to receive and process information, our memory, spatial
and temporal orientation and speech. Therefore, they directly
affect behaviour and the information we receive from the environment.
It should also be borne in mind that unlike what is commonly thought
to be the case, cognitive changes are not solely the result of
learning disabilities or senile dementia, but may often be a temporary
response to stress or depression.
Cognitive changes include the following:
-Memory disturbance.
-Problems of spatial orientation.
-Problems of temporal orientation (when the internal clock which
tells us when to eat or sleep, or indicates the time of year, ceases
to function).
-Difficulty in remembering the steps required to solve a problem.
-Inability or difficulty in speaking, reading, writing or understanding
words (depending on the location and extent of an injury).
