In a previous post, I talked about how designers transmit knowledge, share concepts and process information through language, and how structure and legibility affect the visualisation of messages and inform the design decisions you make on a daily basis.
To help your audience understand your messaging, you need to know how they will receive and decode the information you send.
Scientific study has provided designers with a number of theoretical tools to refine and improve their messages. Among these, some of the more practical tools are chunking, perception, scanpaths, wayfinding and content structure.
In perception, there are two key structures involved, difference and discernment.
Difference threshold and Weber’s Law
Understanding our ability to perceive information and distinguish one information set over another can help designers target their messages for maximum impact.
Weber’s Law of Just Noticeable Differences (no, really!) suggests that there is an identifiable minimum amount of change that can be defined for a viewer so that they are able to notice a difference in any one design
If the amount of perceptual change remains a constant (and can thus be predicted unconsciously by the viewer), then it is easier for your audience to process and distinguish between different types of information. This regular rate of change is known as the ‘difference threshold’.
Weber’s Law can be used to help designers make constructive choices in making information follow an obvious hierarchy.
For example, setting a consistent rule for the differential sizing of type headings, say in 4 point increments, establishes a clear information hierarchy in the mind of the audience.
Similarly, decisions on the relative weights of fonts in typeface design can also be informed by identifying the difference threshold.
User testing of visual assumptions against Weber’s Law can help confirm the designer’s intuition regarding aesthetic considerations and help establish clearer communication with the audience.
