The machines are yellow, but... why?

12 February, 2024

Within the large number of machinery brands that exist today, there is a large percentage of them that apply yellow colour on their equipment. Specifically, approximately 3 out of 4 machines have this colour. This is something we have already internalised, both for people working in this industry and those outside it. Replicas, toys... are always represented with yellow colour. But why?
Caterpillar was the first machinery manufacturer to use yellow colour for its equipment, although not always did they use this colour. For example, at the end of the 20th century, their machines were grey, mainly because they were mostly used for military purposes. This did not change until 1931, when they decided to start using yellow to make the machines more visible on roads and construction sites. What started out as a visibility reason became a marketing reason, as this more striking colour helped the brand stand out more, and fostering brand recall in the minds of the general public was easier. In 1979 the American brand modified the shade of yellow to make it more appealing to the public, and registered it legally associated with its brand.

Cultural and psychological reasons

We tend to associate yellow with construction machines because for decades it was the predominant colour in this industry. That makes cultural reasons why even toy excavators are yellow.
On the psychological side, the fact that we assume that machines are yellow means that we ignore those that are not, which is called “selective perception”, based on the principle that we cannot process all the information that arrives simultaneously, and we must resort to “shortcuts” or biases so that our brain is able to assimilate all the information it is receiving.
Moreover, we tend to perceive things in a way that confirms our past experiences and expectations, while ignoring those that contradict them.