Here are my notes from John Medina’s book Brain Rules: 12 Principles for Surviving and Thriving at Work, Home, and School:

Why sleep is important

Different people need different amounts of sleep, and it changes with age and life circumstances. When it comes to the amount of sleep one should get, generalizing doesn’t work. But there are some things worth taking into consideration:

Cumulative sleep loss creates a deficit which must be paid back later. If you don’t sleep enough today, this week, etc., you’ll have to make up for it later by sleeping even more than you would normally need to.

One study showed that if a student who normally scores in the top 10% gets less than 7 hours of sleep a night during week days (and about 40 mins more on weekends) his or her scores will begin to match the bottom 9% of students who are getting enough sleep.

Another study showed that one night of lost sleep resulted in a 30% loss in overall cognitive ability and drop in performance for soldiers operating complex military hardware. Two nights of lost sleep resulted in a 60% drop.

Other studies showed that when sleep was restricted to 6 hours or less per night, cognitive performance was equivalent to 48 hours of continual sleep deprivation.

In another study, students were given math problems and a method to solve them. They weren’t told that there was also an easier way to solve the problems. Researchers found that if they let students sleep for 8 hours they were three-times more likely to find the easier method.

When people don’t get enough sleep it also affects how the body functions. The body’s ability to use the food it consumes falls by 1/3. The ability to make insulin and extract energy from glucose (which the brain needs a lot of) falls. And the body’s stress hormone levels rise, causing it to need even more of the above.

If this goes on long enough it will speed up the aging process. According to one study, if healthy 30-year olds average only 4 hours of sleep per night for 6 days, parts of their body chemistry become like a 60-year old. It takes about one week to recover.

The number one factor for predicting marriage success

John Gottman’s ability to predict the success or failure of a marriage is close to 90% and he can do it within minutes of interacting with a couple. After years of observation, he identified certain behaviors that hold the most predictive power.

Gottman created an intervention strategy based on improving the behaviors that predict marital success and eliminate the ones that predict failure. His intervention drops divorce rates by nearly 50%. His interventions show couples how to decrease both the frequency and severity of their hostile interactions.

Gottman also noticed that when a couple has a baby, the couple’s hostile interactions increase dramatically. Causes range from sleep deprivation to increased demands from the child. By the time the baby was 1-year old marriage satisfaction had decreased by 70%.

Gottman and a fellow researcher started introducing intervention strategies to married couples while the wife was still pregnant whether the marriage was in trouble or not. They found that babies raised in the intervention households didn’t cry as much and had stronger attention-shifting behaviors. They responded to stress in a more stable way.

The dangers of multi-tasking 

We can walk and talk at the same time, but when it comes to paying attention multi-tasking doesn’t work. The brain naturally focuses on things one at a time, and sequentially.

Three researchers at Stanford university did a study and found that multitaskers, in this case students who spent a lot of time on their laptops during lectures and tended to have multiple tabs open at once were terrible at focusing. They weren’t good at filtering out irrelevant information, they couldn’t organize their memories well and did poorly on every task-switching experiment. They had a habit of thinking about the tasks they weren’t doing and had difficulty keeping things separate in their minds.

There’s a sequential order that the brain goes through every time you switch from one task to another. That’s why we find ourselves losing track of previous progress, wondering where we left off. A person who is interrupted takes 50% longer to accomplish a task and makes up to 50% more errors.

Large fractions of a second are consumed every time the brain switches tasks, making multi-tasking dangerous in some situations. For example, driving while talking on a cell phone is almost as dangerous as drunk driving. It takes only a half second for a driver going 70 mph to travel 51 feet. More than half of visual cues spotted by attentive drivers are missed by cell-phone talkers. Eighty percent of crashes happen within three seconds of some kind of driver distraction. One study showed that simply reaching for an object while driving multiplies the risk of a cash or near crash by 900%.

How to do presentations that aren’t boring 

If you want people to pay attention, don’t start with details. Start with key ideas and form the details around the larger ideas. Meaning first, details after.

Here is John Medina’s proven process for keeping his university students engaged in a lecture:

• Divide the presentation into 10-minute segments, because it’s difficult for an audience to pay attention beyond that mark.
• Each segment should cover a single core subject. That subject should be large, general, and explainable in 1 minute. Use the remaining 9 minutes to cover the details in a hierarchical fashion, making sure that each detail is easily traced back to the general concept. Pause to explain the link.
• If you’re going to go past the 10-minute mark, it should be the start of a different core subject, but related. Repeat the same process of explaining the core concept in 1 minute and linking the details for the remaining 9 minutes.
• You’ll want to make the switch from one core concept to the next by using a “hook”. The hook has to trigger an emotion, such as fear, laughter, happiness, nostalgia, or incredulity. Telling a story that is crisp and to the point is especially helpful. The hook also has to be relevant to the subject.
• If you’re covering multiple core concepts in say, a 1-hour lecture, make sure to stop once in awhile to briefly remind the audience where you’re at in terms of what core concepts have been covered up to that point and where they fit into the overall presentation. This prevents the listener from trying to pay attention to two things at once: what’s being said, and where it fits into the big picture.

Different types of intelligence 

Learning causes physical changes in the brain which are unique to each person. Not even identical twins are wired exactly the same way.

We have many large pathways that are basically the same in everyone, but other smaller ones that vary from person to person based on individual experience. There are a lot of the smaller pathways. That’s why there are different types of human intelligence, such as verbal/linguistic, musical/rhythmic, logical/mathematical, spatial, body/kinesthetic, interpersonal, and intrapersonal.

How to remember more

Memories have different lifespans. Some memories last for only a few seconds, others for days or months, or even a lifetime. We usually forget 90% of what we learn in class within 30 days. And the majority of it is forgotten within the first few hours. The lifespan of a memory can be increased by repeating the information in spaced time intervals. In other words, repeat the information many times, but don’t squeeze the repetitions together, space them out in a systematic way. Maybe 3-times on the first day, once more 3 or 4 days later, and again every 6 months to a year.

The events that happen the first time you’re exposed to information play a disproportionally greater role in your ability to accurately retrieve that information at a later date.

Memory retrieval works best if environmental conditions at the time of learning are recreated. That includes mood. For example, if you learned something while you were sad, it’s easier to remember it if you’re sad at the time of retrieval.

The more you focus on the meaning of the information you’re trying to learn the better you’ll process it and remember it. This is best achieved through relevant real-world examples. The greater number of examples the more likely the information will be remembered. The more personal the example, the better.

In an attempt to fill in gaps, the brain infers, guesses, and even uses memories not related to the event. The brain does this in attempt to create organization. The brain is constantly receiving new inputs and needs to store some of them in places already occupied by previous experiences. New knowledge can become intertwined with past memories as if they were encountered together.

Transforming a short-term memory into a long-term memory can take years. During that time, the memory isn’t stable. Forgetting plays a role in our ability to function. It’s a way of prioritizing. Information deemed irrelevant would cause too much cognitive load. There are people who have a special ability to recall everything, but they tend to have difficulty with meaning.

The power of smell 

Smell can stimulate certain types of memory more so than any other sense, by as much as two-fold, in terms of the  number of events recalled, accuracy, and detail. The sense of smell isn’t fully integrated with our other senses. Instead, it’s closely connected to the emotional learning parts of the brain. That’s why the sense of smell is especially good at evoking the emotional details of a memory.

Smell also affects desire and behavior. Businesses that emit the smell of their products, i.e.; coffee, chocolate, waffle cones, can increase sales substantially (50-60 percent in some experiments). Another experiment caused sales to increase by 200%. It involved emitting the smell of rose maroc in the men’s section of a clothing store and the smell of vanilla in the women’s section. Switching the two had the opposite affect. Though those two smells affect men and women differently, they don’t have the same affect in all settings. For example, the scent of a forest would likely have a different affect at an SUV dealership than would the scent of vanilla. Also, the less complex the smell (fewer ingredients), the more likely it is to increase sales.

The power and deception of vision  

Brain researchers did an experiment with dozens of professional wine-tasters by putting odorless, tasteless red dye into white wine. Every one of the wine-tasters were fooled into believing it was red wine. Vision overrode their other senses.

A phenomenon called Charles Bonnet Syndrome causes some people to see things that aren’t there. Sometimes objects or even people unexpectedly come into the person’s view. These illusions usually occur in the evening and are more common in the elderly, especially those with a damaged visual pathway. Almost all the patients know that the hallucinations aren’t real.

The brain doesn’t actually know where things are. It guesses what things should look like. It does so partially based on past experience. The brain deconstructs the information the eyes are gathering, pushes that information through various filters and reconstructs what it thinks is there. This all happens in the blink on an eye. Visual processing takes up about half of everything our brain does, which explains why it can override other sense.

Amputees sometimes perceive that their missing limb is still there, but that it’s frozen in place. An amputee can sometimes perceive that the missing limb is moving when watching the opposing limb move through a mirror.

Vision is probably the best tool for learning. The more visual an input is the more likely it is to be recognized and remembered. Tests have shown that people could remember pictures with 90% accuracy several days later, even though they saw each picture for only 10 seconds. For oral presentations, the retention rate is about 10%. Text presentations are also far less efficient than photos, because the brain sees words as tiny pictures—that’s a lot of images for the brain to process. Pictorial information is also superior at capturing attention, regardless of the size of the image.