Reducing Extraneous Load

Redundancy effect

Eliminate unnecessary information and do not replicate necessary information.

When information is presented simultaneously in written and spoken form, both sources of information are vying for the same working memory resources, and therefore interfering with each other (i.e. don't read slides from your presentation to your audience if they can read it for themselves).

Moreover, In the image below from Chandler and Sweller's research, three diagrams of the heart were given to 3 groups. Group (a)'s diagram had simple descriptions integrated in the diagram, group (c)'s diagram had simple descriptions as well as longer explanatory text below and group (b)'s had the longer explanatory text integrated in the diagram. Group (c) did worse on an assessment than group (a) because the longer text below image (c) was redundant and therefore interfered during study. It took students half the time to study the information and still score better when using image (a). In general, unnecessary information interferes with learning.

Blue boxes represent simplet text descriptions while the yellow boxes show the locations of longer (fuller) definitions.

Bobis and Sweller looked at this in another experiment. The above is a list of instructions for folding paper that students studied. Those who studied the steps without the text on the right did better - again, the inference here is that the additional text information was redundant.

split attention effect

Information that must be combined should be placed together in space and time.

Imagine getting feedback to an assignment for 4 weeks ago. The assignment's distance in time makes the feedback unhelpful.

Also, Look at the images to the right. The Image showing silver from the periodic table of elements it a description underneath is causing the negative split attention effect. Instead, the image with the integrated information is better.

This is different from the redundancy effect because the information here is not redundant and should not be separated. Information should only be placed together in space and time if it cannot be understood in isolation and is essential rather than redundant.

The image below shows how one might avoid the split attention effect in lab procedures via a strategy called integrated instructions

transient information

Information that disappears that students must hold it in their working memory causes extraneous cognitive load.

PowerPoint or Google slide presentations are often guilty of this. Important information on a slide disappears as we move on to the next one forcing students to hold in their working memory the instructions or information relevant to the next slide.

In image A, you will see a set of slides causing the transient information effect while in image B, the slides have been arranged to minimize this effect.

The YouTube videos we like to use (e.g. crash course kids) are often perpetrators of the transient information effect as they talk too fast and their graphics flash across the screen too quickly. One way to fight this effect is to either show segments of the video (crop it) on mute so that you can narrate the important information or, if what you like about the video is their graphics, then perhaps all you need to do is take a screenshot of a scene and add that graphic to your slides.

During class discussions, important information that is said should be written on the board to be referred to later on a need basis.

Don't do


Dual modality

Not to be confused with dual coding which is what may happen if a teacher makes use of the dual modality effect. The modality effect relates to how information is presented while dual coding relates to how information is remembered. Our working memories have two "channels" the auditory and visual channels. Anything relating to words (spoken or read) gets filtered through the auditory channel while the rest passes through the visual channel. A teacher can increase working memory efficiency by making use of both channels simultaneously.

Put simply, this means using images combined with written or spoken words (avoiding redundancy and split-attention) is helpful to a learner.

worked examples

A common misconception is that teachers call what they are doing "worked examples" but John Sweller would label that as "teacher modeling followed by problem solving". In fact, Sweller's idea of students doing worked examples is more of an in between step between the teacher modeling an example on the board and the problem solving tasks teachers ask their students to do for practice. The main takeaway for teachers regarding students doing worked examples is to persist longer than one intuitively thinks they should - learning takes a long time.

Two strategies for worked examples are described below.

  • Alternation strategy

      • In this strategy, the students and the teacher alternate solving problems. Image A shows how a sequence of alternating worked examples may look like.

  • Faded worked examples

      • In this strategy, teachers complete many multi-step worked examples each time completing fewer and fewer of the steps themselves while the class completes more and more of those steps on their own. Image B shows what this may look like.

Some interpret worked examples as fully solved problem for students to study line-by-line (click here to see such a worked example).

Alternating Worked Example

Faded Worked Example

Self-explanation prompts

Students are self-explaining when they explain an example to themselves in terms of its underlying principles, or when they explain to themselves why a particular principle can be applied to a specific example.

An example of this may be when students are asked to predict the outcome of an experiment based on the scientific principles they've learned before actually running the experiment. Or after a demonstration, students try to explain the principles at play causing a specific phenomenon.

Avoid students encoding incorrect explanations into memory. If you are having students compare and explain correct and incorrect examples, first, know that this increases interacting elements and can increase the intrinsic load. Second, it's a good idea to pair correct and incorrect ideas side-by-side so as to increase the chances students notice the differences.

Self-Explanation in Chemistry

A common trap to fall into when having students do self-explanation is to have them teach themselves what they don't know. The most efficient way to gain expertise in a subject is to borrow it from another expert - not to spontaneously discover it by self-introspection.

the goal free effect

Removing the goal removes a large number of interacting elements associated the means-end analysis which in turn frees up a lot of working memory resources to focus on learning.

The shift in focus from 'getting the answer' to cause and effect as well as the reduced element interactivity is the proposed mechanism behind the goal free effect.

Disclaimer: the most effective way of making use of the goal free effect is to ensure that during tasks/activities, students have restricted actions (i.e. when studying acids and bases they cannot use any old chemicals, they are restricted to using acids or bases), rapid feedback (this ensures that the actions the students take are paired with the correct consequence so that they can see the impact of their decisions) and reliable results (students need to be able to rely on the correctness of the outcomes to each of their action lest they learn something incorrect as a consequence of an unreliable action-outcome pair).

In science classes, a good way to make use of the goal free effect is to have students explore online simulations. Simulations restrict a students actions, give rapid feedback and reliable results. See the PhET simulation here.

What are all the things we can get the balloon(s) to do?