Where Does Memory Come From?


The human memory is crucial to a trial. It is the essence of a lay person’s testimony. So where does memory come from?

In the Organized Mind neuroscientist Daniel Levitin explains.

When we experience an event, a unique set of neurons is activated. The act of remembering something is a process of bringing back on line those neurons that were involved in the original experience… Once we get those neurons to become active in a fashion similar to how they were during the original event, we experience the memory as a lower-resolution replay of the original event. If only we could get every one of those original neurons active in exactly the same way they were the first time, our recollection would be strikingly vivid and realistic. Remembering is imperfect; the instructions for which neurons need to be gathered and how exactly they need to fire are weak and degraded, leading to a representation that is only a dim and often inaccurate copy of the real experience. Memory is fiction. It may present itself to us as a fact, but it is highly susceptible to distortion. Memory is not just a replaying, but a rewriting.

We have a better time remembering unique events. For example, the memory of locking your front door today may be forgotten. You lock the front door every day, so the experience shares similarities with many other door locking times. Making it easier for the brain to get fooled by competing memories.

However, out of the ordinary events are easier to retrieve. “[T]here is nothing competing with them when your brain tries to access them from its storehouse of remembered events.” Memory retrieval requires our brains to sort through multiple instances and pick out the one we are trying to collect.

Evolutionary wise it makes sense that we have an easier time remembering unique events. We need to register the change in order to maximize our chance for survival.

Additionally, having a strong emotion attached to an event, makes it easier to remember. A strong emotion can consist of being frightened, elated, sad, or angry. These emotions make it more likely that we will remember the event. This is because our brain creates neurochemical tags that accompany the experience. It is like placing a highlighter over the event.

Again this highlighting function makes sense from an evolutionary standpoint. If a strong emotion is linked to the event, it’s probably because we need to remember it for our survival. E.g. the smell of rotten food or being backstabbed by a friend. Unfortunately, even though we may have an easier time retrieving the memory, the “highlighter” associated with emotion doesn’t mean the memory is more accurate.

Memory is fallible.

(This post was originally posted on slaw.ca. Views are my own and do not represent the views of any organization.)

Why Multitasking Doesn’t Work


The brain seeks out novelty.  And multitasking feeds that addiction.

How many times today did you check your phone while doing something else? Did you just check it? Did you get some “important” text?

In “The Organized Mind”, neuroscientist Daniel Levitin explains that multitasking is an illusion. When we are multitasking, we are really shifting quickly between tasks. We aren’t doing 5 things at once. We are shifting focus between 5 things. And there is a huge metabolic cost to shifting focus from one thing to another.

Levitin explains that multitasking depletes the brain of neurochemicals, making you more tired. Ultimately putting you in a state of aggression. That is why people who focus on one thing at a time accomplish more and are less tired.

Asking the brain to shift attention from one activity to another causes the prefrontal cortex and striatum to burn up oxygenated glucose, the same fuel [the brain] need[s] to stay on task. And the kind of rapid, continual shifting we do with multitasking causes the brain to burn through fuel so quickly that we feel exhausted and disoriented after even a short time. We’ve literally depleted the nutrients in our brain… repeated task shifting leads to anxiety, which raises levels of the stress hormone cortisol in the brain, which in turn can lead to aggressive and impulsive behaviours… staying [on task] uses less energy than multitasking and actually reduces the brain’s need for glucose.

The brain burns glucose the way a car burns gasoline. In an hour of daydreaming, the brain uses 11 calories. (Daydreaming restores the brain’s neurochemicals.) In an hour of reading, the brain burns about 42 calories. In an hour of sitting in class, the brain burns 65 calories.

So why do we love multitasking? The answer is that we are hardwired to love novelty and accomplishment. When we check our phone, we get to see something new. When we send an email, we get to feel a sense of accomplishment. The brain gets a reward of hormones. Levitin explains:

The very brain region we need to rely on for staying on task is easily distracted by shiny new objects. In multitasking, we unknowingly enter an addiction loop as the brain’s novelty centres become rewarded for processing shiny new stimuli to the detriment or our prefrontal cortex, which wants you to stay on task and gain the rewards of sustained effort and attention… The awareness of an unread email sitting in your inbox can effectively reduce your IQ by 10 points, and that multitasking causes information you want to learn to be directed to the wrong part of the brain.

To make matters worst, multitasking requires decision-making, which further depletes the brain’s energy. Do I answer this message now or later? How do I respond to the email? Interestingly, making little decisions can take up just as much energy as making big decisions.

So next time you hear the siren calls of multitasking, don’t be fooled. “Make no mistake: E-mail, Facebook, and Twitter checking constitute a neural addiction.”


(Views are my own and do NOT represent the views of any organization.)