Surprises About the Brain The stage is small, much smaller than commonly realized. The less you hold in mind at once the better. New concepts take up more space on the stage than ideas you know well. Memory starts to degrade when you try to hold more than one idea in mind. When trying to make a decision between items, the optimal number of items to compare is two. The optimal number of different ideas to hold in mind at one time is no more than three or four.
