You don’t need to teach a child to push harder when confronted with a heavy object. She figures it out. You don’t need to teach a child to pay attention when you shake a rattle. He naturally gets attracted to its sound and motion. You don’t need to tell a child to become calm and joyful when seeing beautiful objects. She just smiles.The human brain has evolved over centuries to interact with physical objects and react to cues in the real world. Interfacing with mobile apps is increasingly more like interacting with these physical objects. We touch, swipe, tap and tilt them.Apps are also responding like physical objects.They slide, bounce, shrink and stretch. The obvious benefit of this, when done well, is that the human brain doesn’t need to be trained to respond. It simply draws upon millions of years of evolutionary learning engraved in our limbic system.I am glad that both Apple with iOS 8 and Google with Material Design are headed in the same direction. In fact, the new Syncplicity for iPhone app also borrows heavily from the real world and, in the process, creates a natural experience that is easy to use and seamless.Let me give three examples of metaphors our brains either love instinctively or have learned over millions of years of human evolution and how they can be used in mobile apps.How objects respond to touchIt is common for physical objects to shrink when you press on them, like paper crumpling into a ball. It is also natural for physical objects to bounce, no matter how little, when they are dropped on the floor. The global gesture of tap and hold in Syncplicity causes the sheet to shrink, just like real sheets of paper. When you swipe the sheet down, it docks at the bottom with a slight bounce. This makes it easy to remember that there is a sheet waiting to be restored. How bubbles captivate the child in all of usBubbles are delightful. They rise to the surface. They naturally evoke an urge to reach out and touch. What better way to offer rich functionality than to use bubbles like animation? Syncplicity’s contextual menus use bubble design to naturally attract users to reach out and tap,exploring the full functionality of the system.These are just a few examples of applying these physical world metaphors to the mobile world in ways that even children understand and love. I am proud of the Syncplicity team for creating a rich and easy-to-use experience that relies on these intuitive metaphors. This is, though, just the beginning of the revolution in UX that leverages human evolution.Just like we ride on the shoulders of those who came before us, this is our humble attempt to provide a platform for others to build on. Try Syncplicity out and partner with us in advancing this revolution even further. How objects slide and stretch when pulledPushing or pulling objects makes them move in the real world – sliding forward, backward or side-to-side. In the case of elastic objects, like rubber bands, they stretch when pulled and go back to their original state when released. Mobile apps can use this metaphor to good effect too. For example, in Syncplicity, tapping and holding the main menu panel results in the left and right panels sliding into view. Swiping to the right or left panel applies the stretching metaphor visually, indicating that if you let go, it may go back to its initial state.