This homophone led me to the dangling carrot as an inducement for behavior. Something that always remains out of reach - a metaphor for a puppet on strings. For carat, I originally looked at diamonds and, naturally, Marilyn Monroe, who famously made the musical rendition of Diamonds are a Girl's Best Friend from the 1953 film Gentlemen Prefer Blondes, her own. Instead, I went with a more sober image from Riccardo Tisci's Spring 2012 Collection for Givenchy. The woman appears physically and psychologically weighted down by the heavy jewels. Certainly, diamonds or gold, measured by their carat weight, can be considered an tool for behavior modification. I did look for images to express "gold digger," but none of those made the cut.
Note: I expect the title and images to do the work of the mood board. That's the purpose after all. However, I often include a little backstory as a way of noting my own thought process, as well as for those who are curious to see how the connections were made.