In the old days, medical students used to walk around with pockets bursting at the seams. Why? Because they were carrying around hand-written notes, cards, and mini textbooks to help them remember all the information they were trying to learn. Many people have described the medical school experience as “drinking out of a fire hydrant.” The volume of information is so great that our limited brains quickly get saturated with information and we’re unable to retain any more data.

When medical students would transition from the classroom environment to the clinical setting, they often relied on a pocket-sized notebook that they often called their “peripheral brain.” Some may have called that book their “second brain,” while others may have referred to it as their “ectopic brain.” Here’s a slight tangent: the word ectopic is defined as something that is in the wrong place. You’re probably familiar with the phrase “ectopic pregnancy” which is used when the developing embryo/fetus is not in the correct place (uterus) and is developing in the wrong place (e.g., in the fallopian tubes).

The medical student’s peripheral brain often lasts for several years because many students carry this book into post-graduate medical training (also called internship and residency). This book often gets very personalized with a wealth of hand-written notes, formulas, and other medical pearls.

Perhaps you think that I’m speaking of the stone ages when I speak of a paper book. Granted, the electronic PDA (personal digital assistant) and the smartphone have revolutionized the concept of a peripheral brain. Having access to the Internet on your handheld device is like having a gigantic book in your pocket. In the pre-PDA era, students had a finite amount of content they could carry in their pockets. Now, the sky is the limit because of revolutionary technology and increasing capabilities of micro computers (also known as ultra-mobile PCs or UMPCs).

So, you may not be a medical student, but do you rely on a peripheral brain? I think many of us have become utterly dependent on one but we may not realize it until we accidentally leave it at home. Then, when we’re somewhere and we suddenly realize that we don’t remember someone’s phone number, we are hopelessly lost! Technology continues to increase our efficiencies, but it also makes us more and more dependent on our peripheral brains. If you rely on a GPS (global positioning system) for directions as you’re driving, then you’re relying on a peripheral brain. If you keep all your phone numbers on your mobile phone, then that phone has become your peripheral brain. If you heavily use a PDA or smartphone and you keep a wealth of important information on that, then you’ve got an electronic peripheral brain in your pocket.