How do we select which sounds to pay attention to? When we walk down a street we ignore the sounds of cars passing by, the gossip of people, and on, but we pay attention to a short, sharp whistle. Even little children know the sound of the ice cream truck. Psychologists have been trying to find out how we select some things over others. Our brains record everything. Hypnosis has shown this to be true. We could not possibly take note of everything around us. Attention allocation operates by combining two functions: the predictive principle and the uncertainty principle. The predictive principle is logical in that the brain searches for the more meaningful from the background "noise". With the uncertainty principle the brain looks for the unusual, the odd thing out. Animal research has shown that they do use both principles. However, tests on humans had clearly shown the predictive principle at work but not uncertainly. New tests show humans use a variant of the uncert