The human eye notices the value of a shape, or area, before anything else, including its color. We notice contrast between light and dark first. Every color, if we were to see it in black and white, has a certain value. Its value is going to be somewhere between white and black (a number 1-10 on the Value Scale).
The loud conversation is comprised of those areas in your art that have the greatest relative Value Contrast, compared to all other areas. You can make any color part of the loud conversation in your art, simply by making sure it is one of the areas or shapes that has the highest value contrast. Color may, or may not, affect the loud conversation. It is all depends on the value of the color.