• http://www.seobythesea.com Bill Slawski

    I hate doing this, but I have to disagree, Gord.

    The rule of seven isn’t meant to apply to the amount of scannable material that we have in front of us as we are working. Even George Miller called that a misapplication of his research. A short snippet from Dr. Miller in his response to being told that his work was being used in a fashion like you are suggesting (in the context of billboards only containing seven items, so that they don’t cause accidents if they have too many more):

    But the point was that 7 was a limit for the discrimination of unidimensional stimuli (pitches, loudnesses, brightnesses, etc.) and also a limit for immediate recall, neither of which has anything to do with a person’s capacity to comprehend printed text.

    Here’s a link to the original paper, rather than the wikipedia entry:

    The Magical Number Seven, Plus or Minus Two: Some Limits on Our Capacity for Processing Information

    Please note that even the Wikipedia page discusses the urban mythology surrounding Dr. Miller’s research. Armed with this, does it make you come to some slightly different conclusions? I hope so.

  • http://www.seobythesea.com Bill Slawski

    Just a little more, Gord.

    From George Miller’s paper, the conclusion:

    And finally, what about the magical number seven? What about the seven wonders of the world, the seven seas, the seven deadly sins, the seven daughters of Atlas in the Pleiades, the seven ages of man, the seven levels of hell, the seven primary colors, the seven notes of the musical scale, and the seven days of the week? What about the seven-point rating scale, the seven categories for absolute judgment, the seven objects in the span of attention, and the seven digits in the span of immediate memory? For the present I propose to withhold judgment. Perhaps there is something deep and profound behind all these sevens, something just calling out for us to discover it. But I suspect that it is only a pernicious, Pythagorean coincidence.

    These pages are also worth a look on the subject:

    Edward Tufte’s discussion on: The magical number seven, plus or minus two: Not relevant for design

    And, a link on that page leads to this paper:

    How magical is Miller’s famous Seven for HCI issues? (pdf)

    James Kalbach’s article is also worth a look:

    The Myth of “Seven, Plus or Minus 2”

    Denny C. LeCompte’s paper:

    3.14159, 42, and 7±2:
    Three Numbers That (Should) Have Nothing To Do With User Interface Design

    A snippet from that one:

    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. Thus, the narrow range of generality implied by the research findings cannot support the wide variety of situations to which people try to apply this heuristic. Based on the relevant data, user interface designers should probably forego application of the 7 ± 2 heuristic altogether.

  • http://www.outofmygord.com Gord Hotchkiss

    Bill, you made a good point, but I think there are two distinct things here. One is our ability to recall distinct pieces of information and one is our ability to scan and assimilate visual displays. I refer to them seperately in the column. These are two cognitive limits that play a part in our interactions with the search engine, and they both impact the nature of that interaction. I’m not trying to imply they’re interchangeable.

  • http://www.seobythesea.com Bill Slawski

    Hi Gord,

    The cognitive limitations that Miller discusses are within a completely different and much more limited context than the one that you present, and yet it seems like the basis for some of your research, which is why I couldn’t help myself but bring it up.

    When you write, “Now let’s take both those principles and apply them to an interaction with a search results page. Here’s how the two tend to work together,” it does seem like you are attempting to use Miller’s research to stand for a limitation of a person’s cognitive ability to scan and interpret materials directly in front of them. It’s the same context as the concern about billboards that caused Miller to state that his research was being misinterpreted.

    Isn’t it just as easy to hypothesize that a searcher expects to see relevant results within the top few links to pages that appear after a search, and that after looking at the first three or four may decide that the results do or do not hold value, and may then decide whether or not to revise their query? Thus, not being a matter of limitations of our ability to scan, and to retain a certain amount of information within our human memory banks, but rather to be able to review and discriminate about the relevance of results based upon a review of the first few results?

    Doesn’t the fact that we read left to right and top to bottom also play a role in the shape of those results? That we go from top to bottom when we read would also play a role in that shape. If the first three or four results don’t look promising, there seems like little value in proceeding too much further down the page, regardless of whether my ability to scan and recall is tied to some magical number or not.

    So, do we only scan the top few results because that’s all we are capable of, or do we scan them because we have the ability to make a judgment based upon information directly in front of us, that we don’t have to necessarily recall after the fact? In other words, what you are calling a limit, I’m calling a decision.

  • http://www.outofmygord.com Gord Hotchkiss

    Good point. I think the fact that most of us find something relevant enough in that top consideration set to at least click on is highly pertinent to the interaction. Thanks for adding your insight!

  • http://www.seobythesea.com Bill Slawski

    Thank you, Gord.

    I’m really happy to see someone exploring search from the perspective that you are. I may question some of what you are doing a little, but I really appreciate the level of inquiry that you are bringing to the topic of search.

  • Andy Edmonds

    Miller’s work was focused on the auditory loop and memory for acoustic data.

    There is some critical importance to the 7+-2 quantity that seems to pervade the cognitive system, but for the phenomena described here, you’re much better off studying the “subitizing” research that specifically looks at visual attention:

    It’s amazing how even professionals trained to PhD levels in cognitive psychology promote an over-interpretation of Miller’s (ancient) work. See Just and Carpenter’s theories on working memory for a more recent take in which both storage and processing are considered a single resource.