As previously mentioned, colour is sometimes used to send diametrically opposed signals depending on discipline. This occurs, for example, within many of the disciplines that comprise the life sciences.

Take, for example, the red/pink and green/yellow ratio in histology and biomedicine. In these fields of study, red or pink signals healthy or exposed tissue, while green and yellow are more likely to signal bacterial infection or the presence of pus, in other words, something pathological.
In botany, however, the signals are reversed; green indicates a healthy and vital plant, while red might represent an infestation, for instance, of rust fungus.

Hence, the palette is the same in both disciplines, but what each colour means is reversed.

Now take a moment to reflect on the following questions, in order to relate what you have read to your own field of study.

How is colour used within your discipline? Are there any colours that have a specific meaning?
Can you remember how you learnt about that practice/convention?
Imagine someone who is about to create a visualisation, but is unfamiliar with the consensus regarding colour use that exists within that particular discipline. What consequences might there be if a visualisation uses colour encodings that go against established practice, do you think?