Spotted this quick news release via kottke (a while back now – this blog post has been sitting in my “Drafts” folder for a couple weeks):
EurekAlert! - How much can your mind keep track of?
- new research has shown that, when someone is trying to solve a new problem or do an unfamiliar task, the number of individual variables that they can handle is relatively small; four variables are difficult, while five are nearly impossible
- when problems are more familiar, people are able to break a larger number of variables into more manageable chunks, treating several variables as a single chunk
Which, of course reminded me of this (in)famous article:
The Psychological Review - The Magical Number Seven, Plus or Minus Two: Some Limits on Our Capacity for Processing Information by George A. Miller (1956, vol. 63, pp. 81-97)
Everybody knows that there is a finite span of immediate memory and that for a lot of different kinds of test materials this span is about seven items in length. I have just shown you that there is a span of absolute judgment that can distinguish about seven categories and that there is a span of attention that will encompass about six objects at a glance.
Which has since been repudiated in its applicability to interface design:
Internetworking - Three Numbers That (Should) Have Nothing To Do With User Interface Design
(E)ven when it is cited correctly, Miller’s work is discussed as if the scientific understanding of short-term memory had not advanced at all in the last half century… More contemporary experiments show that an individual’s capacity for short-term remembering depends heavily on the nature of what is being remembered.
At best, Miller’s 7 ± 2 figure applies to immediate serial recall for a sequence of familiar, easy-to-pronounce, unrelated, verbal stimuli presented auditorily with no distracting sounds within earshot.
Net Return - Seven, plus or minus two. What’s the relevance for web design? (PDF, 90 kb)
- it is information scent, and not a user’s ability to remember a list of items, that determines their success in using a navigation structure that presents a large number of links
- information scent arises from wording used in labels and links that clearly conveys to the user what sort of information can be found if they click link
Also picking up on the news release from EurekAlert!:
beyond bullets - 7 x 20 = Overload
Many people justify 7 bullet points per slide by citing the George Miller article, but what’s always missing in the arithmetic is the total number of bullet points across all of the slides; e.g., 7 bullets per slide times 20 slides equals 140 bullet points.
In turn, beyond bullets links to these two items: