The experiment used symbols with values attributed to them, so the diamond was the most valuable, followed by the red circle, followed by the green circle. This

The experiment used symbols with values attributed to them, so the diamond was the most valuable, followed by the red circle, followed by the green circle. This reward context meant that they were seeking these symbols, assessing their value and influence with regard to the goal: getting the diamond. In your example with the sign and deer, the goal is driving safely - the deer is a negative presence, something to avoid, the sign is a negative presence, something to avoid, which you are comparing using visible area. You've been trained in different ways regarding deer and billboards, and they behave differently - billboards don't move, deer can. The deer seems more salient, unless I really do need a heart transplant because perhaps the context of my future health - greater than duration of my car trip - is more valuable to me than my health during the car trip?