Trying to get your head around big things can be a tall order, says Chrissie Giles, editor of the Wellcome Trust’s post-16 science magazine, Big Picture. It’s time to appreciate the power of the picture for sizing up information.
It happens most meetings. The person I’m talking to grabs a napkin, rips a page out of a notebook or reaches for the white board to sketch out a drawing that helps them make their point.
Pictures, drawings and diagrams can help people understand. In Big Picture, a biology magazine aimed at students aged 16 and over, we’ve been experimenting with infographics as a way to help our readers get to grips with numerical information for several years.
Infographics, popularised by information designers such as David McCandless, present information and data in a graphical way. They can be a particularly effective means of showing comparisons in the size of different things – for example, how different billion dollar amounts are spent globally (from the $316 billion in bribes received by Russian officials to the $18 billion yoga industry).
One of the trickiest things that I find we have to illustrate is big numbers (sometimes, really big numbers). For example, one fact which featured in the infographic for the issue on exercise, was that humans make 900 000 000 000 000 000 000 molecules of adenosine triphosphate (ATP) per second. Another, this time in Inside the Brain, was that there are 150 000 000 000 000 synapses in the human neocortex, part of the cerebral cortex of the brain. Such large figures can be mind-boggling.
“We have problems understanding big numbers in an intuitive way,” says Dr Roi Cohen Kadosh, a Wellcome Trust Research Career Development Fellow working at the University of Oxford. “This is because we represent numbers in a logarithmic fashion. Therefore the differences between 1 and 2 are perceived in the first instance as more than 1,243,621,312 and 1,234,453,234.”
So, although numbers go up in a linear fashion, the way they are represented in our brain means that an objectively greater difference between two large numbers does not seem as big to us at first glance as the difference between 1 and 2.
Asked how we might help people grasp big numbers in a more meaningful way, Cohen Kadosh suggests that a pictorial cue can help boost understanding of how big big is. Pictures can be especially helpful for making comparisons.
In the latest issue of Big Picture, we used to-scale radiation symbols to show the radiation dose associated with different activities (shown below). This was a neat and easily digestible way of showing relative effects.
A CT scan of the head gives you a 71 times greater dose than that from eating a medium-sized bag of Brazil nuts. The annual radon dose present in Cornwall is 1560 times the radiation dose found in your nutty snack. And you’d need to eat 20 000 bags of nuts before you reached the level at which changes in blood cells can be seen.
Of course, adds Cohen Kadosh, you can also deliver information in terms of things that your audience might be familiar with (x times the earth’s population, y times the length of a double-decker bus etc.).
It’s key to have the phrase “familiar with” at the front of your mind though. No matter how many different permutations of planetary journeys I read (70 times to the sun and back/8000 return journeys to the moon/three times the distance of Pluto from the sun), all I understand after my virtual tour of the universe is that were the DNA taken from all my cells and unravelled, it would stretch a long way.
As for something I am all too familiar with, that distance is roughly equivalent to over 150 million round-trips from my front door to my office. Not a task I’d relish, but certainly one I can relate to.
The latest edition of Big Picture, Inside the Brain, is available in print and online now. Additional teaching resources, including infographics and animations, are also free to download from the website.