Monday, 7 December 2015

Hour of Code 2015

Hi all, this week marks the start of the Year's 'Hour of Code' event. All across the world, students will be investing time in developing their understanding of programming language - regardless of ability level or age!

Computers are everywhere, but fewer schools worldwide teach computer science than 10 years ago. The good news is, we’re on our way to changing this. If you've heard about the Hour of Code before, you might know it made history. More than 100 million students have tried an Hour of Code.

With the Hour of Code, computer science has been on homepages of Google, MSN, Yahoo! and Disney. Over 100 partners joined together to support this movement. Last year, every Apple Store in the world hosted an Hour of Code and even President Obama wrote his first line of code as part of the campaign.

This year, let's make it even bigger. Why don't you join in the Hour of Code 2015? Get involved with an Hour of Code event during Computer Science Education Week, December 7-13.

Try the Hour of Code yourself -- everyone can benefit from learning the basics.

Get started at 

Wednesday, 2 December 2015

What happens in your brain when you make a memory?

You might imagine memory is a Santa’s sack of life events and the first half of jokes. You would be wrong. Neuroscientist Dean Burnett explains all

We all have memories, as far as I can remember. But where do these memories come from and how do they get made?

People often compare the brain to a computer, but the brain doesn’t have USB slots that allow you to pick up new information by jamming a flash drive in your ear. That would be convenient, if a little painful.

So where do we get all this information sloshing around in our skulls? You might imagine human memory is a bit like a Santa’s sack filled with life events, song lyrics and the first half of jokes. But in truth, “memory” is not one single solid thing. It is a term covering lots of types of recollections that are surprisingly distinct, and used constantly in different combinations by a typical human.

Short-term memory – like writing your name with a sparkler

We’ve all heard about short-term and long-term memory. While people tend to use the phrase “short-term memory” to refer to our recall of things that happened recently – in the last hour or day – technically speaking, it’s actually far more fleeting. Short-term memory typically lasts between 15 and 30 seconds: it’s a bit like writing your name in the air with a sparkler. Any memory that can be recalled after that length of time is a long-term memory.

In computer terms, short-term memory is like the RAM – it holds the information we’re currently working with or using for cognitive tasks (thinking). This can be new information delivered by our senses, for example, or old information retrieved from the long-term memory. Neuroscientists theorise that all this thinking is supported by patterns of neuron activity in the prefrontal cortex (that bit at the front of your brain).
Long-term memory - information becomes a physical ‘thing’

Luckily, for memories we actually want to keep, there’s also long-term memory. If short-term memory is the RAM of a computer, long-term memory is the hard drive, which keeps everything from your failed screenplays to Minesweeper scores.

Unlike short-term memories, long-term memories have a physical presence in the brain, and aren’t dependant purely on specific patterns of activity. Neurons make new physical connections and synapses with each other when a new long-term memory is formed. This connection endures whether it’s being used or not.

Long-term memory can be split into explicit and implicit memory. Implicit memories include habits and skills that we can do automatically, such as rolling a cigarette, driving a car, forging your boss’s signature on expense forms.

Explicit memories are things we’re consciously aware of and are intentionally trying to remember. There are two kinds of explicit memory: episodic and semantic. Episodic memory is memory for things and events that happened to you. Semantic memory is for more general knowledge. Knowing Paris is the capital of France is a semantic memory, remembering being sick on your trip to Paris is an episodic memory.
Encoding – a terrifyingly complex tapestry in real time

When we actually want to learn something, it is long-term memories we are interested in. So how are they formed? The first step is to encode a piece of information – otherwise it quickly disappears, like breath on a mirror.

Information is channelled to the hippocampus, the brain region crucial for the formation of new memories and one of the only places in the brain where brand new neurons are regularly generated. The hippocampus links all of the relevant information together and encodes it into a new memory by forming new synapses. It’s basically like someone knitting a terrifyingly complex tapestry in real time.

But not all information is equal in the eyes of the hippocampus. “Important” things are encoded more readily and effectively than routine or incomprehensible things, like an uneventful daily commute, or the lyrics of a dance song in a language you don’t recognise. The hippocampus will prioritise those that have been rehearsed repeatedly in the short-term memory, or those with a strong emotional component. The hippocampus is selective because it is very busy.
Finding a home for your memories

Coding a memory is all well and good, but it is useless if it has nowhere to go. Finding a storage place is the next step.

Newer memories, once consolidated, appear to reside in the hippocampus for a while. But as more memories are formed, the neurons that represent a specific memory migrate further into the cortex. As a result, memories are stored throughout the brain. It’s a bit like the internet, which is made of information spread all across the planet and accessed via countless connections.

Similar memories tend to clump together – spoken memories near the language centres, visual memories near the visual cortex – and there’s a lot of redundancy too; you can have several memories for the same thing. Every time they are activated they are strengthened. Human memories aren’t stored like books in a library; they’re constantly being updated and tweaked.

Recalling memories you’ve forgotten you forgot

So how do you go about getting the bits you need out of this weird, ever-shifting library of information? It might seem as though lots of the so-called long-term memories have actually turned to dust because there are plenty of things you’ve forgotten: old addresses, passwords, deadlines for articles about the memory system that you promised to write.

The problem here is not that it has disappeared, but rather that you can’t recall it. It’s a bit like losing a glove – you still own a glove, it’s in your home somewhere, but you can’t use it.

Recall is a very impressive but slightly mysterious process. When we want to access a memory from the dark recesses of our brain, signals from our frontal cortex link to that memory via uncertain means, and the memory is reconstructed from the information available. The more often you use the memory, the easier it is to find.

Revising and remembering is a crucial part of the learning process. And there are things you can do to make it easier – some stranger than others. Being in the presence of some of the elements from the original memory helps retrieval. For example, if you learned something while in a swimming pool, you’ll remember it better while in a swimming pool at a later date (they’ve actually shown this).

Is there such a thing as too many memories? Maybe. Ever tried to learn a new phone number and then found it impossible to remember the old one, even though you had it for years? Constantly updating memories can supposedly “supplant” existing ones, so you end up remembering things differently. This is known as “interference” and can lead toforgetting. As far as I can recall.

This blog is the first of a new series exploring the psychology and neuroscience of learning. Get involved with the Use your head series by joining the discussion on #useyourhead or pitching your ideas to

Memory Encoding

Encoding is the first step in creating a memory. It's a biological phenomenon, rooted in the senses, that begins with perception. Consider, for example, the memory of the first person you ever fell in love with. When you met that person, your visual system likely registered physical features, such as the color of their eyes and hair. Your auditory system may have picked up the sound of their laugh. You probably noticed the scent of their perfume or cologne. You may even have felt the touch of their hand. Each of these separate sensations traveled to the part of your brain called the hippocampus, which integrated these perceptions as they were occurring into one single experience -- your experience of that specific person.

Experts believe that the hippocampus, along with another part of the brain called the frontal cortex, is responsible for analyzing these various sensory inputs and deciding if they're worth remembering. If they are, they may become part of your long-term memory. As indicated earlier, these various bits of information are then stored in different parts of the brain. How these bits and pieces are later identified and retrieved to form a cohesive memory, however, is not yet known.
Although a memory begins with perception, it is encoded and stored using the language of electricity and chemicals. Here's how it works: Nerve cells connect with other cells at a point called a synapse. All the action in your brain occurs at these synapses, where electrical pulses carrying messages leap across gaps between cells.
The electrical firing of a pulse across the gap triggers the release of chemical messengers called neurotransmitters. These neurotransmitters diffuse across the spaces between cells, attaching themselves to neighboring cells. Each brain cell can form thousands of links like this, giving a typical brain about 100 trillion synapses. The parts of the brain cells that receive these electric impulses are called dendrites, feathery tips of brain cells that reach out to neighboring brain cells.
The connections between brain cells aren't set in concrete -- they change all the time. Brain cells work together in a network, organizing themselves into groups that specialize in different kinds of information processing. As one brain cell sends signals to another, the synapse between the two gets stronger. The more signals sent between them, the stronger the connection grows. Thus, with each new experience, your brain slightly rewires its physical structure. In fact, how you use your brain helps determine how your brain is organized. It is this flexibility, which scientists call plasticity, that can help your brain rewire itself if it is ever damaged.
As you learn and experience the world and changes occur at the synapses and dendrites, more connections in your brain are created. The brain organizes and reorganizes itself in response to your experiences, forming memories triggered by the effects of outside input prompted by experience, education, or training.
These changes are reinforced with use, so that as you learn and practice new information, intricate circuits of knowledge and memory are built in the brain. If you play a piece of music over and over, for example, the repeated firing of certain cells in a certain order in your brain makes it easier to repeat this firing later on. The result: You get better at playing the music. You can play it faster, with fewer mistakes. Practice it long enough and you will play it perfectly. Yet if you stop practicing for several weeks and then try to play the piece, you may notice that the result is no longer perfect. Your brain has already begun to forget what you once knew so well.
To properly encode a memory, you must first be paying attention. Since you cannot pay attention to everything all the time, most of what you encounter every day is simply filtered out, and only a few stimuli pass into your conscious awareness. If you remembered every single thing that you noticed, your memory would be full before you even left the house in the morning. What scientists aren't sure about is whether stimuli are screened out during the sensory input stage or only after the brain processes its significance. What we do know is that how you pay attention to information may be the most important factor in how much of it you actually remember.
The next page provides details on how information is stored in short-term and long-term memory.