Brain Rules

This is the first of many planned book write-ups. I’m thinking of calling these type of posts BookMarc’s. Speaking of horrible humor, in addition to being a hacky comedian, I am also a real geek and often take lots of notes when reading a book. 

Regarding the structure of these posts, what I don’t like in a book review/recommendation is for someone to simply highlight passages of a book in their kindle and then spew it into a synopsis about the book. Additionally, bulleted lists of contents from the book are also lazy and lacking. Articles like that a) don’t make me want to read the book as I already have a synopsis of it and b) aren’t that enjoyable to read anyways. 

Instead, what might make sense is to take a few concepts from a book and then elaborate on them with my thoughts or connections that I have made from other resources. My process may start off looking like a top ten list but then a few items emerge that cause my thinking to expand on the subject matter. My thoughts may not even largely come from the book in question. The hope though is that you as a reader are interested enough in the book to read it. 

As far as the quality of the books, I won’t waste my time or yours with any books that I don’t recommend. So it should be implied that any book that I do write about is a good one. 

This post is about Brain Rules by John Medina.

Brains With Legs

Our brains were built for walking 12 miles a day. 

Humans were not meant to sit. We did not evolve by laying on a couch or lounging in an office chair for most of the day. Instead, our species developed by walking…a lot by today’s standards. The average amount that a human walked for most of our existence is estimated at 12 miles a day.

Back when I used to count my steps ( I was an obsessive idiot so had to stop) the average goal was about 10,000 steps a day. Most fitness trackers will tell us that walking 10,000 steps a day is an active one. That is only around 5 miles; less than half of what we have typically done throughout our species’ existence. 

Times were different then. Now we have responsibilities. They require us to be chained at a desk at work and stuck on our couch at home and strapped into our cars when traveling between those places. For days where I am not worried about being active but still count steps, I can do less than a thousand steps a day…no sweat…literally. Why would I perspire when I wear the same thing a few days in a row?

Despite the conveniences and responsibilities that modern times bring, our brain was not meant to be sedated. Physically moving around helps our brain to process ideas or emotions. Have you ever experienced, or heard people talk about, how going on a run cleared their head? That outcome has happened to me as well. Before being active, my thoughts are all jumbled, I am stressed out and the world is caving in on me. Mercifully, somewhere about a mile into a walk or run, a super simple solution to my problems seems to magically appear. What is happening is that the activity is helping my brain to function and reorganize itself. 

Friendless Bores

People don’t pay attention to boring things.

The human brain focuses its attention on those things that are sudden or surprising like a cat snapping to attention when a laser from a laser-pointer hits the floor. We crave stimuli that keep us guessing. Otherwise, we mentally check out. 

This idea just seems obvious…right? Whether read, watched, listened to, during a conversation, or simply doing nothing, if one is not engaged, they can’t pay attention. One of the key precepts to creating content is that you have to spice things up periodically or you will lose your audience. 

It is really easy to think from the perspective that other things are boring. But what about yourself? How are you not boring? Why would people pay attention to you? Think about it for a while.

Tangentially my thoughts on this subject go to a snippet of a conversation on a podcast where Penn Jillette is speaking to Tim Ferris with the transcript from the conversation as follows:

“Tim (Jenison) said to me that when he’s meeting somebody, if he learns two things about them and can guess the third, he’s really uninterested. Like if he finds out that they’re vegan and they like The Grateful Dead, and then he finds out they’re against nuclear power, he says, “I’m kind of done. I kind of know that kind of person.” And it’s really interesting to look at oneself and say, “If someone has two cliche data points on me, can they guess the third to be absolutely right?”

… it’s one of the ways, probably unfairly, that you can decide how close you want to be to somebody is just, if they can tell you something really early on that surprises you. As we build our theory of other minds, we get these points, and then we guess the other points. And if you can’t do that, that’s someone you want to fall in love with.”

I think that I am boring to outsiders. I read non-fiction books and make weird notes in them so my wife thinks I am boring. My hobbies, like reading as just mentioned, are boring. My desk job, as my kids during lockdown have found, is boring. My routines which I repeat most days are boring. I eat the same things. My views are boring or at least predictable. To be clear, I am not bored, but I can understand how anyone outside of myself would find me boring. This passage made me wonder: what is it that makes someone else pay attention to me? Do I even want others to pay attention to me?


Information coming into your brain is immediately split into fragments that are sent to different regions of the cortex for storage.

Your brain is constantly processing information. Not only is your brain taking in the information, evaluating it, and responding to it, but your brain is also storing information. 

Most information does not even get processed in our memory at all. The brain filters out anything in the periphery or that is not considered important to the task at hand (See the Invisible Gorilla Experiment). Things that do get through enter the short-term memory. Short-term memory can only hold a limited amount of items. The brain holds items in short-term memory for about 15-30 seconds. Most experiments show that the brain can juggle about seven distinct items at a time.  It is typically during the half-minute that we are assessing this information that our brain decides whether to place it in our long-term memory to recall it at a later date. In long-term memory, it is filed away around related events, subject matter, and/or vocabulary. Once in the long-term memory, a trigger would then jostle our memory and that piece of information is retrieved.

So what does this have to do with deja-vu? As you may already know, deja-vu is the sensation that you have already lived through the present situation before. In times where I have had deja-vu, I rack my brain trying to remember if something like this had indeed happened before, I had a dream along those lines, or if someone told me about their similar experiences before. But from a sensory standpoint, the smells, touches, emotions, and even dialogue are familiar. The situation is too rich and congruent to be similar to some other moment. So what is happening?

One explanation, and the reasoning that I adhere to as a result of this book, is that the brain is not storing the new stimuli in the short-term memory as it usually does but is instead skipping to storing it in your long-term memory. People are used to accessing their long-term memory as something that has happened in the past and so that experience feels like it is distant. However, with deja-vu, if you are living through something real-time and yet experiencing it through a vehicle that is meant to bring up old things, your mind is in dissonance. The theory goes that your memory is having hiccups as your short-term and long-term memory are not behaving as they typically do. 

Sleeping With A Lion

Chronic stress, such as hostility at home, dangerously deregulates a system built only to deal with short-term responses.

Could you sleep with a ferocious mountain lion laying right next to you? 

Our brains evolved to process seriously threatening stimuli which are characterized as stress. This original stressor would be like a predator lurking in the grass waiting to pounce on us. Not only does that predator, once spotted, take all of our attention but all of our energy is concentrated to manage that stressor and escape it. A good example would be watching a gazelle run like crazy to escape a lion. A gazelle is usually not faster or more cunning than a lion. But for a short time and where it is of life-or-death importance to the gazelle, they will attempt to escape and often succeed. This survival extinct is the general context that we as humans learned to deal with stress.

We now have new stresses from our modern life. Things like budget concerns, marital issues, getting the kids to classes on time, work communication, and projects. These are not stresses like one where “in the next five minutes, will I get eaten?” It would be absurd to even make that connection. But the brain knows no difference. 

Life stresses don’t go away. A bad relationship with your significant other doesn’t just get better. Having a crappy boss is that way all the time while you are in that job. Your boss isn’t just nice, then mean for an hour, then nice again forever. These are long-term issues or chronic stress. Put simply, your brain thinks that it is going to be eaten constantly when living with chronic stress. It does not matter that you academically know that you won’t die due to those stresses. Your brain just doesn’t work that way.

When describing this, I use the scenario of a bad marriage. There is always fights on money or suspicions that people are cheating or even digs that someone is a slob and doesn’t carry their weight around the house. Maybe the fights happened in the kitchen table or maybe they happened right before bed when the kids were asleep to spare them. Either way, bad relationships are a chronic stress in life; a mountain lion waiting to pounce and eat you. Now go to bed and get those eight hours of cherubic dozing so that you can fight another day. Good luck. 


Here are a few of the large concepts from the book that I have noted. To be perfectly fair, I don’t remember whether I created this list or if it was provided in the book. It has been about a decade since I digested it.

  • Exercise often
  • Avoid being bored or boring
  • Learn and practice new skills
  • Sleep is a priority..afternoon naps included
  • Avoid stress-build-up
  • Tinker