Reading 7: Perception 101

by Mike Gleicher on February 2, 2017

Due Date: before class, Monday, February 27th read the 3 things from group A (you can skim #3, but be sure to look at the pictures). For Wednesday, March 1st, please read (#1 or #2) and #3 from group C. (assignment link)

Perception could be a whole course onto itself – or several. Our goal is to get some relevant bits so help us understand how people see in order to make images that communicate better.

There is so much to learn, and so many possible sources, that I don’t know where to start.

To make matters worse, there are two separate things to learn: (1) the perception basics and (2) their ramifications on visualization.

The minimum required readings for the perception basics (group A):

  1. Chapter 1 of Ware’s Visual Thinking for Design “Visual Queries” (link)
  2. Chapter 2 of Ware’s Visual Thinking for Design “What we can easily see” (link)
  3. “Attention and Visual Memory in Visualization and Computer Graphics” by Healey and Enns. Available online. Warning: this survey is a little dense, but it gets the concepts across with examples. Don’t worry about the theory so much. Get a sense of what the visual system does (through the figures, and the descriptions of the phenomena), and skip over the theories of how it does it (unless you’re interested).
    There is an older, online version as Chris Healy’s web survey which has lots of cool pre-attention demos. But the text in the paper is much better, and the paper includes more things.

There is a fourth reading that I wanted to put into this category (Ware Chapter 3 LINK) – but this reading is already getting to be too big (since you need to read some of the stuff below). We’ll come back to it later in the semester, but you might want to read it now since it fits in well with the Munzner chapter on layout from last week.

And some optional readings for perception basics (group B):

  1. The nature and status of visual resources. Steve Franconeri. (pdf here) – this is a survey, similar to Healey and Enns above, but written more from the psychology side. The first part, where he characterizes the various kinds of limitations on our visual system is something I’ve found really valuable. The latter parts, where he discusses some of the current theories for why these limitations happen is interesting (to me), but less directly relevant to visualization (since it is mainly trying to explain limits that we need to work around). I think these explanations may lead to new ideas for visualization – but its less direct of a path.
  2. We (Steve, myself, and some of our students) have written a survey paper (paper page) on some other things the visual system can do (and why it can matter for vis). We call it “visual aggregation” and in psychology they call it “ensemble encoding.” It might be useful to skim through for the pictures and diagrams.  I will talk about this stuff (at least the work that we did) in class.

Cairo, in Chapter 5 of the functional art (link), gives his summary of this topic. While his summary is fun and intuitive, I think it’s best to get it with a little more depth from the Readings in group A. You might want to read this (optional) chapter as a review.

(group C) There is important work that tries to quantify what the visual system is good at for visualization. Broadly, this area is called “graphical perception” – and it’s valuable since it tells us what encodings are good for what things. The original seminal papers are still referred to today, and you should be aware of them. As well as their modern extensions.

You need to experience where the whole graphical perception thing got started. There are different versions of the paper, you may read either one.

  1. (short) Cleveland and McGill. Graphical Perception and Graphical Methods for Analyzing Scientific Data. Science 229(4716), 1985.  (online library)
  2. (long) Cleveland and McGill. Graphical Perception: Theory, Experimentation, and Application to the Development of Graphical Methods. Journal of the American Statistician, 79(387) 1984.  (online library)

Jeff Heer and Michael Bostock re-created these results using crowdsourcing (many more participants, but much higher variance for several reasons). This paper is nice for many reasons, but a relevant one is that it’s a more modern presentation of (basically) the same results.

  1. Crowdsourcing Graphical Perception: Using Mechanical Turk to Assess Visualization Design. Jeffrey Heer, Michael Bostock ACM Human Factors in Computing Systems (CHI), 203–212, 2010  PDF (607.4 KB) | Best Paper Nominee

Normally, I’d pick a few other experimental papers to add, but we’ll get to those later in the semester. For now, just know that there are a lot more experiments helping us understand encodings.

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