How the Brain Works: It’s all about layers part 1

The brain has a layered structure. You can think of it a bit like the layers of the Earth, from the crust, to the mantle, down to the burning, ancient core.

The outer layers of the brain process information without caring too much about goals or emotions. Some call it ‘cold cognition’. The inner layers increasingly process information in terms of goals and emotions, so-called ‘hot cognition’.

spider-1403889352yvkThe innermost layers coordinate with the functioning of the rest of the body. When I see a1280px-man_running_scared_cartoon_vector-svg spider, cold cognition recognises the visual pattern, hot cognition gets worried, the body is informed that its heart should race in preparation for fight-or-flight action, and cold cognition prepares the instructions to jump. The layers work together as an integrated whole.

This week’s blog explores how the outer layer, the cortex, works.

The Outer Layer (aka The Cortex)

As we’ve seen, the cortex is big in humans compared to other animals. The back and the front do different things.

The cortex, is a sheet of neurons for processing information. The sheet of neurons, 2 millimetres thick, is just a bit smaller than a sheet of A3 paper, and it needs to be crumpled up to fit it in the skull.  The sheet processes information without caring too much about the results. Where you are on the sheet doesn’t radically change how the information is processed, it just changes what is processed.

The back part of the cortex houses regions involved in sight (vision), hearing (audition), and the processing of space. Senses are processed along two routes. One route, called the ‘what’ pathway, tries to identify what things are. The other route, the ‘where’ pathway, processes where things are in space. You might want to combine this information: catch a cricket ball (howzat!) but don’t catch a snowball (duck!).

The motor areas are towards the front. At the boundary is an area for sensing the body, and the motor circuits for controlling parts of the body. Further towards the front are areas involved in planning, decision-making, and control. As we’ll see, these are still sort of motor circuits.

Between the back and the front, the sensory and motor systems are organised in hierarchies, moving from simple to complex. You can think of these hierarchies as being like a tower with many floors, with a separate tower for each sense. Each floor combines the work done below, and each floor has a farther view than the floor below. The lowest floor spots patterns in sensory information. The next floor up spots patterns within patterns. The next floor, patterns within patterns within patterns. Sensory and motor systems are trying to see patterns within patterns within patterns – and then make connections between the screenshot-2019-03-13-at-18-30-44patterns.

After a while, the upper floors of the towers might know a thing or two about what patterns are likely. Based on their knowledge, the upper floors like to make suggestions to the lower floors on what they may be perceiving (just to help out, mind). The upper floors of the towers for the different senses talk to each other, across cables strung between the upper floors, to see if they can agree what’s out there in the world. The upper layers are connected to the frontal parts of the brain, to pass on conclusions and see if their view fits with expectations.

The motor system has a hierarchy too, but its higher levels are different. They’re about patterns more distant in time. The lowest levels are about immediate actions. The higher levels are about more complex sequences of actions, further forward in time. The lowest level says ‘Do it!’ (primary motor cortex). The next layer says, ‘Prepare to do it’ (supplementary cortex). The next layer up says, ‘You may want to do it sometime in the future’ (prefrontal cortex). A complex sequence of motor actions to be carried out at some future point in time can be described as a plan. Pre-frontal cortex, the planning and decision-making part of the brain, can also be seen as the top of the motor system hierarchy, looking the furthest forward in time.

We saw in the section on evolution that humans have more cortex. This means that humans can build their towers higher than other animals. In their senses, humans can discern more patterns within patterns, more complicated concepts; and in their motor systems, they can build further forward, creating plans into the more distant future.

Read more at howthebrainworks.science!

Teachers and educators on what research means for them: Harry Fletcher-Wood

harry-fletcher-wood-photo
We are delighted to welcome him to the CEN to answer some questions for our blog.

What is the importance of formal evidence, beyond what teachers know works in their classroom?

As a new teacher, I improved a lot through trial and error, and trying what colleagues were doing.  This was powerful: you get rapid feedback from students if you’re boring them or they don’t understand what you’re talking about, so I was able to refine some aspects of what I did.  But there are some things which we are unlikely ever to discover through trial and error: for example, the phenomenon of desirable difficulties: making tasks harder for students (and so seeing worse immediate performance) can increase what they retain in the long-term.  That’s pretty counter-intuitive: without evidence, I’d have been reluctant to believe this or act upon it.  More broadly, learning from trial and error is slow: students come to school because they wouldn’t learn everything we’d hope in eighteen years of trial and error; I think evidence helps students in similar ways – teachers will keep getting better, but acting on evidence can accelerate their improvement.

What enables teachers to take a more evidence-based approach?

I think it’s getting used to questioning what you’re being told, and finding good sources of evidence. The intermediaries are key here: as a history teacher, I didn’t have the training or experience to critically analyse papers in experimental psychology; nor did I have the time.  We need to make this easier for teachers by providing clear, actionable summaries which remain faithful to the underpinning research.

Can you give any specific examples from your experience of how an evidence-based approach has changed practice for the better?

A few years ago I was designing a new history curriculum for Key Stage 3 students.  I’d begun to read around how much students forget, and why.  So instead of designing a curriculum which rattled straight through the topics, I designed it so that we kept revisiting key ideas, key periods and key disciplinary approaches.  Students began Year 7 with a chronological world tour, giving them a rough sense of how Ancient Roman life differed from the Middle Ages, for example.  The next year, we did another chronological course, focused on British political history.  The next year, something similar based around war.  The evidence convinced me that, rather than relying on teaching it really well first time, I needed to design my curriculum to revisit the key ideas from different perspectives.

More recently, as part of the programme I lead for teacher educators, we’ve written a curriculum for teacher educators, designed to offer both a structure and material they can use to help teachers understand how students learn, and adapt their teaching accordingly.  We’ve rooted it in cognitive science.  I’ve seen teacher educators design their entire professional development programme around this, helping teachers understand the evidence and teach accordingly.

I am a teacher who wants to know more about the research evidence; where should I start?

I got into the evidence via Twitter and blogs.  I’ve shared some of my favourite people to follow and blogs here and a list of some of the most useful and interesting papers I’ve read here.  I’d also recommend attending a ResearchED conference: they bring together teachers interested in research and researchers interested in sharing what they’ve learned with teachers: so you end up with a good combination of accessibility, usefulness and rigour.

Are there specific areas of teaching or learning where we need better evidence? Where are the research gaps? 

I’m fascinated by how we take good ideas and make them work in the messy reality of individual classrooms.  I’d love to see more research which offers teachers the underlying ideas in a promising area of research, supports them to develop their own ways to act on them in the classroom, and rigorously measures the results.  The biggest gap isn’t exciting research or determined teachers, but bringing those two together in ways which respect both the evidence of the researcher and the wisdom of the teacher.

For more from Harry, as well as the links already mentioned, you can follow him on Twitter