Many of us have steeled ourselves for those 'needle in a haystack' tasks of finding our vehicle in an airport car park, or scouring the supermarket shelves for a favorite brand. A new scientific study has revealed that our understanding of how the human brain prepares to perform visual search tasks of varying difficulty may now need to be revised. When people search for a specific object, they tend to hold in mind a visual representation of it, based on key attributes like shape, size or color. Scientists call this 'advanced specification.'