We use cookies to give you a better experience. Carry on browsing if you're happy with this, or read our cookies policy for more information.

Skip main navigation

The science of perception and cognitive load

In this video, we look at how we, as humans, interpret the world around us, focusing on how the eyes and the brain process visual information.
In this video we’re going to dive into a bit more of the data-driven aspects of delivering great, data-driven presentations. And specifically we’re going to look at the science of how humans visually process the world around them, and specifically things like graphs and data. We’ll start with a quote in this one, just like we had in previous ones. This time from a pretty smart guy, Albert Einstein, who famously said, “Make everything as simple as possible, but not simpler.” I think that is a perfect quote to start this section. So let’s start with a bit of a science lesson, where we talk about how the eyes and the brain work together to process data and to intake the world around us.
At any given point in time, the eyes and the brain are processing hundreds of thousands of little bits of information. And the way the brain processes that data is through a couple of different stages of memory. The first stage is called sensory memory, and sensory memory holds on to information for less than a second. It is, essentially, subconscious. And what sensory memory is there for is to act as a buffer. For all those hundred thousands of bits of information, the brain really only cares about a small fraction of them. And what sensory memory does is it weeds out all the other stuff, and just lets through the things that it believes are useful and necessary for you to function.
But sensory memory is going to be really important for us, because even in that less than one second, the brain is subconsciously processing the things that you’re showing to it. And we can use the processing that happens there to our advantage. So we’ll come back to that in a second. Let’s continue to walk through the stages of memory. So if things make it through sensory memory, they make their way into working memory. Working memory is somewhat akin to short-term memory. So if you’ve heard the term short-term memory before, working memory is fairly analogous to that. In working memory, we have a bit more time to play with, but still it’s pretty short.
There’s something like fifteen seconds of retention that happens in working memory. And it’s important to note that in this stage of memory, the brain can really only hold on to five to seven bits of information. This is going to be key for us, right? So if we’re able to make our way through sensory memory, and now we’re in working memory, realising that this part of the brain and this part of memory can’t hold on to that much stuff, it’s really just trying to figure out, okay, what do I have here, and where do I need to file it? Because ultimately, it’s going to file it in long-term memory, and that’s where we store everything.
But where we’re going to spend a lot of time, in terms of building great graphs and visuals, is trying to optimise for this working memory. Try to optimise for the fact that the brain can’t, in this stage, handle that much. And we need to make it easy on the brain. We need to make it very clear what we’re trying to get across. In the words of Albert Einstein, “We need to make it as simple as possible, but not simpler.” Just put out there what we need the brain to intake. But let’s back up and start with sensory memory. And remember I said there is some processing that actually happens in sensory memory, and that’s called pre-attentive processing.
And this, it really is subconscious, but there is processing that happens in that sub-second when the brain is seeing all that stuff around it. There’s been a lot of work on that sensory memory and the pre-processing that happens there. And what scientists and researchers have found is that there is a set of attributes that exist that the brain can process in that sensory memory; in that subconscious memory, if you will. And those are called pre-attentive attributes. And there’s really four categories that scientists have put these attributes in. The first is form. And form is things like length, how long the line is, or width, how wide a line is. Size, shape, those types of things.
So as you look at these, you can kind of see how the brain would immediately pick up on this line is shorter than this one, or wider than this one. So the first is called form. The second is color. And it’s not just the shade of color, but it’s also the intensity of that color. So as long as there is enough difference in intensity, the brain in that subconscious mode can actually pick up on the intensity of color, as well. The third is position, so spatial position; where is it relative to the other dots, and how is it grouped relative to other things on a page? And the last is motion.
The brain can pick up on, oh I just saw this thing move over here or over there. So all of these things we have in our toolkit that we should be thoughtful in using, because again, we’re trying to maybe show a graph, show a piece of analysis and have our audience be able to understand what it is we’re trying to show them. We should make use of these pre-attentive attributes in doing that. I want to give you a little example of this pre-attentive attribute, just so you don’t have to take my word for it. I’m going to put up some data on a screen, and I’m going to have it up there for only a fraction of a second.
It will be only able to be processed by this sensory memory. It’s going to be up there for less than a second. But pay attention to your screen, and I’m going to flash it up there and see if you can get across what I’m trying to get across.
Did you see it? My guess is most of you saw a bunch of dots, with one dot that was a different color in the middle. Again, it was up there for only a fraction of a second. This is a great example of pre-attentive attributes, and using color thoughtfully in your graphs. And we’ll spend a fair amount of time in subsequent sections talking about how to do that. But color is one of those tools that’s going to be really useful in getting the brain to focus on the thing you want to focus on. So let’s go back to working memory.
As I mentioned, this is a place where we’re going to have more space and time to deal with; to be able to get our concepts across. And the concept that I want to focus on, as it relates to working memory, is a concept called cognitive load. Cognitive load is the total amount of mental effort it takes in working memory to get a concept across. And every concept has some inherent amount of cognitive load. The problem is that oftentimes there’s a bunch of ancillary cognitive load that isn’t relevant to solving a particular problem – to understanding a concept – but that we have to deal with.
And many times, we as presenters, when we’re presenting a graph or a piece of analysis, there’s maybe three points that we need to get across on a graph, but we end up showing thirteen inadvertently. And the way we really want to get this across, the way that we’re going to optimize and build great graphs and build great visuals, is about understanding this concept of cognitive load. It’s going back to that Einstein quote about making things as simple as possible. As we spend the next couple of sections really beginning to refine our graphs, you’ll see that most of building great graphs is about taking things off, rather than adding things.
In this video, we look at how we, as humans, interpret the world around us, focusing on how the eyes and the brain process visual information.
Why is reducing cognitive load so important when you are trying to communicate something to your audience?
This article is from the free online

Business Analytics: The Data Explosion

Created by
FutureLearn - Learning For Life

Our purpose is to transform access to education.

We offer a diverse selection of courses from leading universities and cultural institutions from around the world. These are delivered one step at a time, and are accessible on mobile, tablet and desktop, so you can fit learning around your life.

We believe learning should be an enjoyable, social experience, so our courses offer the opportunity to discuss what you’re learning with others as you go, helping you make fresh discoveries and form new ideas.
You can unlock new opportunities with unlimited access to hundreds of online short courses for a year by subscribing to our Unlimited package. Build your knowledge with top universities and organisations.

Learn more about how FutureLearn is transforming access to education