Thank you everyone!
Yes, that’s part of it. The colour choices aren’t really based on the colours of the pears, it’s using the tonal value of different colours to show the 3D form and the direction of the light. It helps to understand how to draw the form in monochrome (e.g. pencil or charcoal), as preparation, I like to draw shapes like this. Or you could use a black and white image as a reference, it might make it easier to see the tonal values and get away from what you think the colours should be. I hope you have fun doing some multicoloured painting!