The debate goes on as to whether excessive smartphone use deteriorates neurons and rots your brain cells. While no hard evidence exists to back up these claims, neuroscientists have performed case studies and discovered that engaging in multi-tasking duties could result in chronic distraction, therefore affecting short-term memory. And when taking into account the numerous tasks (social media, games, etc.) we use our mobile devices for, one has to question whether our cognitive skills are on the decline. That's why it's recommended people take time out from their day to enhance their smarts and with the help of these brain-training programs, you can stimulate the mind without having to put down the smartphone or tablet. Here are 15 Apps That Will Make You Smarter.