How to Revise A Level Biology: Chunking

A guest blog from Dr Jenny Shipway, who studied biochemistry at university and now works in science communication and education training.

Breaking It Down

Step by Step

Understanding and remembering all the information required for A Level Biology is a real challenge. So anything that reduces the workload and overall effort required must be a good thing.

One of the problems is that there is so much to take in, including complicated concepts that require understanding of multiple other complex ideas. There is a bottleneck in our ability to process information for learning which can get jammed if you try to think about too much at once; it’s called Working Memory.

Working memory isn’t a particular part of the brain (the brain’s function is highly distributed) but rather a capacity of the brain. It’s where new information is held while it is consciously thought through and processed to create new understandings and definitions. The products of this thinking can then be moved into your long term memory (memory is the residue of thought).

You can get a feel for the limitations of your working memory by trying to process a list of items. Try this:

Starting with the list of three digits, read the numbers then shut your eyes and mentally add them up. Don’t use any tricks, just do it straight. If you can do it, move on to the next, longer, list.

How many numbers can you process like this? How does it feel when you lose track of things?

Three 2 8 3
Four 3 1 7 9
Five 7 4 8 2 6
Six 4 9 3 1 8 2
Seven 5 2 7 3 4 6 9

Because Working Memory prevents us thinking of more than a small number of things at once, as humans we need ideas to be broken down into manageable chunks for learning. This is why we have step-by-step guides, bullet points, and why this sentence only has three items.

Educators call this ‘chunking’.

Child building very unstable looking tower of wooden blocks. An allegory for how building on misconceptions can make life difficult.

But is the bottom layer stable?

Shaky Ground

The complex concepts of A level Biology are carefully broken down by teachers and educators into manageable chunks for you to mentally chew upon. They are then presented (you hope) in a sensible order that allows you to build up your understanding.

It’s like making a huge, complex LEGO model - you make small sections first, then join them together to create larger structures.

The problem comes when you make an error at the beginning. You might not realise until you have already built a large - but, you now realise, unstable mental structure. If your learning is based on an early false premise, you could have been wasting time and mental effort thinking about things in all the wrong ways.

You’ll need to go back and start from scratch. But worse, you can’t dissassemble what you’ve built. All that misguided thinking has left its indelible mark in your brain, and when you call upon the topic in the exam, which version will your brain give you?

How to Revise

Frustrating as it may be not to romp through a topic and meet all your studying objectives, it’s best to progress with care.

Check your understanding of each chunk before you move on. If you’re not sure, go back through the materials and think some more. If you don’t understand a foundational premise, then moving on will waste your energy building a misconceived and confusing mental model. You remember what you think about, and if you’re thinking about something wrong, it’s hard not to remember it wrong.

In a nutshell:

  • Break things down into manageable chunks for mental processing

  • Check you understand each chunk before using it to build bigger concepts

  • If you think might you have something wrong, stop and check rather than trying to push on