Pretty much everyone who has used a computer has lost the position of their cursor at some point in time. Reaction is to give the mouse a shake or to drag your finger back and forth on the trackpad and let your eyes key to the motion of the cursor on your screen to find where it is at. Well in the newest version of OS X the designers have used this knee jerk reaction to your advantage and included a new feature.
In OS X 10.11 El Capitan when you shake the mouse your cursor will grow in size for a brief instance making it much easier to spot, even if you have more than one screen connected to the machine. For those users out there that either need to move their mouse around quickly for the work they do or that just don't want this feature on it is easily disabled in System Preferences. Just go to System Preferences > Accessibility > Display and then uncheck the “Shake mouse pointer to locate” box.
There are other new features like better facial recognition, natural language spotlight search, and a better split screen experience as well."