# Illegal Numbers - Numberphile

Your brain can only count to four | Strings of Words I made this little demonstration to show how your brain counts low numbers. The brain can only count to four on its own — to count anything higher, it needs to be taught a trick — which we call “counting.” If you don’t have time to count, you will have a hard time counting numbers higher than 4. So, try to count how many red dots appear below. The dots show up in a grid, so if you play long enough you’ll notice patterns and be able to guess better, but you’ll get the idea. Credit goes to reddit user SurfKTizzle for bringing this to my attention in response to the thread “If someone asks me ‘how many apples are on the table’, and I say ‘five’, am I counting them quickly in my head or do I remember what five apples look like?” His answer is as follows: The human mind has two systems for representing numbers: a subitizing system for numbers up to four[1] , and an approximate ratio estimation system for larger numbers.