Cognitive load theory and other “loads” teachers need to know
In recent years, strategies drawn from cognitive science have become essential in the teaching toolkits of many teachers. These strategies have various implications for practice, but many of them stem from a single fundamental idea: that the human brain is a system of finite resources, with only a limited capacity to process information.
From this idea of limited capacity comes the belief that we can impose a “load” on our processing systems. This load, depending on the thought, can be too small, too large, or in the “Goldilocks” zone: just right. In the academic literature, these ideas about limited capacity and its effects are referred to as “load theories”.
The educational implications of limited capacity have been widely debated, but what has been much less discussed is the fact that there are actually a number of different bottlenecks in human processing flow. Thus, there is more than one “load” theory, and each has its own implications for how we learn.
Before we get too deep into our charging discussions, it might be helpful to clarify what we’re really referring to.
Cognitive sciences: perceptual load
The first process in which capacity limitations affect our ability to process information is attention. Our ability to pay attention to any one of the many stimuli present in our environment at any given time is actually surprisingly limited and relatively fixed.
In experiments, finding a target, such as the letter “X” on a six-letter display, can be enough to seemingly exhaust our attention span.
We can see whether ability has been achieved by measuring whether or not other non-task-related stimuli (distractors) affect people’s performance in finding the target letter.
At high levels of perceptual load, the effect of the distractor is greatly reduced, causing virtually no slowing of response. At lower levels of perceptual load, the distractor is processed to a much greater degree and thus causes greater impairment. This is because when task-relevant material is not enough to fill our capacity, we automatically process other things in the environment.
I find it helpful to imagine attention as a glass that we always have to fill. If we don’t fill it with task-relevant information, the rest will automatically be filled in with other stimuli from the environment.
Let’s take an example. Imagine doing a find-the-difference task with only three objects in the image. You would probably find the different object very quickly, and also very easily. You’ll also likely find that you don’t get lost in the task; you are always aware of background noise or movement in your environment. This is because the low level of attentional load in the task does not exhaust our attentional capacity (it does not fill the pint glass), so we are processing other things as well.
Now imagine a more difficult task of spotting the difference, with a hidden change in a complex image of about 30 objects. You’ll likely find this task much more difficult, but you’ll also likely be much less aware of other things going on in your environment as you complete it. This task would fill the attention glass, due to its increased perceptual load, leaving you less likely to process anything else.
Imagine attention like a pint glass that we always have to refill
This is what the perceptual load theory is. But what are the implications for classroom practice?
- Teachers might like to experiment with ways to increase the attentional load of presentations. By providing complementary information on multiple sensory modalities, you can aim to fill pint glasses with students’ attention. Dual codingwhen done successfully, could be an example.
- Try to set appropriate challenging tasks as they are more likely to fill attention capacity.
- Reduce the number of obvious potential non-task-related distractors in classrooms. For example, eye-catching displays should not be around the board or at the front of the room where you want attention to focus.
Working memory load
Once we have given our attention to a particular piece of information, it can continue further in the processing flow.
We now enter a second capacity-limited environment – working memory – and thus find ourselves under a new theory of load: working memory or cognitive load.
Confusingly, research in psychology and cognitive neuroscience treats these terms as roughly interchangeable, and neither refers to the “cognitive load theory” (CLT) teachers may be most familiar with. – that which deals with the pedagogical implications of a limited capacity. . We’ll come back to CLT soon, but for now we’ll just analyze the “working memory load”.
The capacity of working memory has been estimated at about four “chunks” of information. A chunk can be something as small as a single letter (if we have no significant connection to the information or no previous experience with such tasks), but it can contain much more information in large amounts. other circumstances, based on our expertise. For example, a complete chessboard arrangement might only occupy one piece in very experienced chess players.
Working memory is also crucial for keeping track of our current goals and prioritizing processing relevant chunks for the task. This means that overloading working memory with too much information or an overly complex task can make people more susceptible to distraction and poor task performance.
You may notice that, interestingly, this is the opposite of the effect of depleting our ability to perceive. When perceptual load is high, we become more resistant to distraction because we don’t process competing information that is irrelevant to the task.
Overloading working memory with too much information can make people more susceptible to distraction
Conversely, when working memory load is high – making it difficult to track and prioritize what we should be dealing with – distraction will be increased. This assumes that the initial perceptual load is low and that some attentional processing will therefore have overflowed onto elements unrelated to the task.
Some of the implications of workload theory in the classroom could be:
- Teachers should reduce the number of steps in given instructions at all times or break tasks down into manageable blocks.
- It is helpful to provide students with instructions for an assignment in written form or another format that they can refer to.
- Teachers need to manage the complexity of tasks to prevent them from becoming overload – although that does not mean making things as easy as possible, since an appropriate challenge will occupy perceptual ability more effectively.
Perceptual and working memory capacity appears to develop throughout childhood. Perceptual ability reaches adult levels at about age 12; earlier than that, a smaller amount of information is needed to fully load the children’s ability.
Working memory, on the other hand, seems to develop a bit later, around mid-adolescence.
Cognitive load theory
But what about CLT, the staple of evidence-based teaching and learning presentations of recent years? Cognitive load theory builds on the implications of the above two load theories to produce a more education-specific theory of ‘instructional design’. In other words, it considers how we should design learning and education experiences, given the existence of limited capacity bottlenecks in our processing system.
It is sometimes suggested that CLT is a theory based on working memory limitations but, in fact, a number of the “effects” noted by the theory are also the consequence of short attention span. The “divided attention effect” (where performance is impaired by having to divide attention between complementary information in two different sources or locations) is the most obvious of these, but another example is the of transient information” (where information is removed before the learner has had time to process it properly).
The latter is partly the product of our limited perceptual load capacity and the fact that we always fully fulfill our perceptual capacity. This means that as soon as the target information is removed, other information not relevant to the task floods in and competes for processing in a limited working memory.
If we are dealing with redundant hardware, there is not enough space to take care of all the necessary information
The so-called “redundancy effect” (when information that is not needed or repeated unnecessarily leads to less successful learning) is also likely to be partly due to our limited attentional capacity. If we process some redundant hardware, there is not enough space to process all the necessary information.
In contrast, the “modality effect” (where complementary material presented through both auditory and visual channels leads to better learning) takes advantage of the fact that the capacity of attention and working memory appear to be slightly larger when distributed over different sensory modalities.
So we have a system of two distinct, and sometimes seemingly slightly paradoxical, theories of limited ability, with another educational theory built on top of it.
That’s a complicated picture, and that’s without taking into account other overlapping educational theories, such as Richard Mayer’s “cognitive theory of multimedia learning.”
It is perhaps understandable that there can sometimes be some confusion.
Still, the next time a DPC session starts to overwhelm you with ideas about limited capacity, it might be worth checking to see if the speaker knows exactly what load he’s talking about.
Michael Hobbiss is a professor of psychology and researcher in cognitive neuroscience