Answer as fast as you can: how many cats are in the image up top? Did you answer without counting them individually? Probably not – but if you were pushing yourself, there's a good chance you tallied them in groups of three or four. Now, researchers say they've identified a small tangle of neurons that makes this speedy form of quantification possible.
The ability to quickly recognize a quantity of something without individual counting is called "subitizing." In the latest issue of Science, researchers say they've identified a small grouping of around 80,000 neurons just above each ear that facilitates this time-saving mental trick.