Before you just place any old photo into an online course or informational website, it's a good idea to think about whether a realistic graphic is required. And if so, how much realism will be most effective? By realism, I mean how well a graphic appears to be a successful copy of its referent. A common assumption is that more realism corresponds to greater comprehension. But this assumption is not based on fact. Surprisingly, a lot of research points to the opposite; realistic graphics are frequently not as effective as those with reduced realism.
The realism continuum
One way to think about realism is in terms of fidelity, or how much an image resembles something recognizable. On a continuum, visuals with the highest fidelity are photographs in full and natural color and photorealistic 3D renderings. You can tell when a graphic is high-fidelity, because you will see a lot of detail, depth, shadow, texture, and nuance of color that nearly replicates what we you see in the physical environment. In the Figure 1, the photo on the left has the greatest fidelity.
On the other end of the continuum are visuals with low fidelity, such as line drawings, silhouettes, and icons. Low-fidelity images uses fewer visual elements and qualities that resemble a recognizable object. Reducing realism reduces the fidelity of the image. The line drawing on the right in Figure 1 is a low-fidelity image.
Low-fidelity graphics and learning
Low-fidelity graphics can be more effective for learning when you need to
- provide an explanation to people with limited knowledge of the content
- focus only on essential details
- ensure viewers recognize an object quickly
- strengthen the impact of a message.
For example, you might choose low-fidelity graphics in a beginners cooking course that is explaining the use of various utensils. In contrast, high-fidelity photographs would work best when teaching more experienced chefs about presentation of the final meal.
Advantages of low-fidelity graphics
There are several cognitive advantages in using low-fidelity graphics:
Quick visual scanning: When we read an image, we scan it to extract significant information. A graphic composed of a minimum of visual elements, such as a line drawing, will take less time to scan and assimilate compared to one that is more complicated, such as a natural scene in a photograph.
Less information in working memory: Working memory has a limited capacity and is easily overloaded. Distilling a graphic down to its essential visual elements minimizes the amount of information that working memory has to simultaneously manipulate.
Fewer distractions: The presence of unnecessary elements can distract the viewer from focusing on the key message.
Fewer misunderstandings: Superfluous information can potentially cause misunderstandings. A minimalist approach could avoid this problem.
Less information to process. Many cognitive researchers think that as the brain processes visual information from a graphic, it removes the nonessential sensory input and converts it into a "bare bones" representation of crucial information. Low-fidelity graphics, therefore, require fewer transformations and take less time to get them ready for encoding into long-term memory.
Many times, you can achieve the most effective visual communication by abstracting and simplifying a graphic. You will need to balance the goal of reducing realism enough to improve cognitive processing, while at the same time, leave enough detail so that viewers will comprehend the graphic as it was intended.