I think the expression behind this sentence is, an object Colored yellow is generally more noticed... Like if you wear a yellow cap in a crowd u will easily be noticed... Again safety helmets are often seen in yellow color for the same reason

I would go with David's first choice of 'instinctive'. ie The vivid yellow colour can arouse an 'instinctive' sense of alarm in the eyes of the viewer. 'Fundamental' or 'elemental' work as well. The idea is that this colour works on our alarm emotion in a very fundamental/elemental/instinctive way.

It's hard to be sure without knowing the context. It could mean "instinctive" (especially in nature) or "low level".