I just read chapter 6 in the Encyclopedia of Human-Computer Interaction: Data Visualization for Human Perception by Stephen Few. This is a lovely description of why (and how) we need to use our knowledge of human perception and cognition in order to make effective and good data visualizations.
– To visualize data effectively, we must follow design principles that are derived from an understanding of human perception.
– Although data visualization usually features relationships between quantitative values, it can also display relationships that are not quantitative in nature. Visualizations that feature relationships between entities can be enriched with the addition of quantitative information as well.
– When you know what story you want to tell, make a list where you write down what the display needs to achieve in order to tell your story in a good and clear way.
– We should always judge a visualization’s merits by the degree to which we can easily, efficiently, accurately, and meaningfully perceive the story that the information has to tell. To do this, we must understand the perceptual strengths and weakness of various graphical means for displaying particular stories. To do this, we must understand perception.
– Gestalt principles of perception (descriptions of visual behavior):
- Proximity: Objects that are close together are perceived as a group.
- Similarity: Objects that share similar attributes (e.g., color or shape) are perceived as a group.
- Enclosure: Objects that appear to have a boundary around them (e.g., formed by a line or area of common color) are perceived as a group.
- Closure: Open structures are perceived as closed, complete, and regular whenever there is a way that they can be reasonably interpreted as such.
- Continuity: Objects that are aligned together or appear to be a continuation of one another are perceived as a group.
- Connection: Objects that are connected (e.g., by a line) are perceived as a group.
– Preattentive visual processing is that part that automatically occurs in the brain prior to conscious awareness.
– Studies in attention and memory are revealing our surprisingly limited ability to hold multiple items simultaneously in awareness.