http://discovermagazine.com/2010/nov/15-the-brain-router-in-our-heads-processing-bottleneck/ Telford speculated, the brain needs time to reset itself after a pulse of thought before it can carry out another one. If we don’t have enough time between two tasks, we slow down on the second one—a lag known as the “ psychological refractory period .” Each time we perform a task we perform it in three steps. Step 1: Take in information from the senses. Step 2: Figure out what to do in response. Step 3: Carry out that plan by moving muscles. The mental activity that takes place in Step 2 includes some of the most sophisticated forms of thought we are capable of: weighing lots of information, thinking about our short-term and long-term goals, and figuring out how to meet them. But when we have any two simple decisions to make, we must wait for the first task to move through a bottleneck before taking on the second. Instead of carrying out many steps simultaneously, we have to do them one at a t...