Cybernetics and Design – Poka Yoke, Two Hypotheses and More:

sonic screwdriver

In today’s post I am looking at “Design” from a cybernetics viewpoint. My inspirations for today’s post are Ross Ashby, Stafford Beer, Klaus Krippendorff, Paul Pangaro and Ranulph Glanville. The concept I was originally playing around was how the interface of a device conveys the message to the user on how to interact with the device. For example, if you see a button, you are invited to press on it. In a similar vein, if you see a dial, you know to twist the dial up or down. By looking at the ideas of cybernetics, I feel that we can expand upon this further.

Ross Ashby, one of the pioneers of Cybernetics defined variety as the number of possible elements(states) of a system. A stoplight, for example, generally has three states (Red, Green and Yellow). Additional states are possible, such as (blinking red, no light, simultaneous combinations of two or three lights). Of all the possible states identified, the stoplight is constrained to have only three states. If the stoplight is not able to regulate the traffic in combination with similar stoplights, acting in tandem, the traffic gets heavy resulting in a standstill. Thus, we can say that the stoplight was lacking the requisite variety. Ashby’s Law of Requisite Variety states that only variety can destroy (absorb) variety. This means that the regulator should have enough variety to absorb any perturbations in order to truly manage a system. Unfortunately, the external variety is always larger than the internal variety. In other words, the regulator has to have the means to filter out unwanted external variety and it should amplify the internal variety to stay viable. An important concept to grasp with this idea is that the number of distinguishable states (and thus variety) depends upon the ability of the observer. In this regard, the variety of a system may be dependent on the observer.

With these concepts in mind, I will introduce two ideas (hypotheses) that I have been playing with:

1) Purpose hypothesis: The user determines the purpose/use of a device.

2) Counteraction hypothesis: When presented with a complex situation, the user generally seeks simplicity. When presented with a simple situation, the user generally seeks complexity.

Harish’s Purpose Hypothesis: The user determines the purpose/use of a device.

The user is external to the design of a device. The user at any given point has more variety than the simple device. Thus, the user ultimately determines the purpose of a device. How many times have you used a simple screwdriver for other purposes than screwing/unscrewing a screw?

Harish’s Counteraction hypothesis: When presented with a complex situation, the user generally seeks simplicity. When presented with a simple situation, the user generally seeks complexity.

The user has a tendency to move away from the perceived complexity of a device. If it is viewed as simple, the user will come up with complex ways to use it. If it is viewed as complex, the user will try to come up with simple ways to use the device. Complexity is in the eyes of the beholder. This can be also explained asUpon realizing that something is not working, a rational being, instead of continuing on the same path, will try to do the opposite. A good example is a spreadsheet – in the hands of an expert, the spreadsheet can be used for highly complicated mathematical simulations with numerous macros, and alternately, in the hands of a novice, the spreadsheet is just a table with some data points. In a similar way, if something is perceived as complex, the user will find a way to simplify the work to get the bare minimum output.

The Cybernetic Dance between the Designer and the User:

There is a dance between the designer and the user, and the medium of the dance is the interface of the device. The designer has to anticipate the different ways the user can interface with the device, and make the positive mannerisms attractive and the negative mannerisms unattractive. In the cybernetics terms, the designer has to amplify the desirable variety of the device so that the user is more likely to choose the correct way the device should be used. The designer also has to attenuate the undesirable variety so that the user will not choose the incorrect ways of use. If the design interface is providing a consistent message each time, then the entropy of the message is said to be zero. There is no change in the “message” conveyed by the design. One of the concepts in Lean is poka yoke or error proofing a device. From what we have seen so far, we can say that a successful poka yoke device has the requisite variety. The message conveyed by the device is consistent and the user always chooses the correct sequence of operation.

Krippendorff explains this nicely in terms of affordances of a device: [1]

When an interface works as expected, one can say with James Gibson (1979) that the artifact in question affords the construction that a user has of it; and when it does not work as expected, one can say that the artifact objects to being treated the way it is, without revealing why this is so.

Krippendorff also explains that the interface does not carry a message from the designer to the user. This is an interesting concept. Krippendorff further explains that the user assigns the meaning from how the user interacts with the device. The challenge then to the designer is to understand the problem, and determine the easiest way to solve it.

Different people may interface rather differently with the same artifact. What is a screwdriver for one person, may be an ice pick, a lever to pry a can of paint open, and a way to bolt a door for another. Human-centered designers must realize that they interface with their artifacts in anticipation that the result of their interactions affords others to meaningfully interface with their design—without being able to tell them how.

An interface consists of sequences of ideally meaningful interactions—actions followed by reactions followed by responses to these reactions and so on—leading to a desirable state. This circularity evidently is the same circularity that cybernetics theorizes, including what it converges to, what it brings forth. In human terms, the key to such interactions, such circularities, is their meaningfulness, the understanding of what one does in it, and towards which ends. Probably most important to human-centeredness is the axiom:

Humans do not respond to the physical qualities of things but act on what they mean to them (Krippendorff, 2006a).

Variety Costs Money:

Another concept from the cybernetics viewpoint is that adding variety costs money. In theory, a perfect device could be designed, but this would not be practical from a cost standpoint. Afterall, a low price is one of the ways the designer can amplify variety. A good story to reflect this is the design of the simple USB. A USB cord is often cited as an example for poka yoke. There is only way to insert it into the port. When you think about it, a USB pin has two states for insertion, of which only one is correct. There is no immediate standard way that the user can tell how it can be inserted. Thus, the USB lacks the requisite variety and it can lead to dissatisfaction of the user. Now the obvious question is why this is not an issue on a different connector such as Apple’s lightning cord, which can be inserted either way. It turns out that the lack of variety for the USB was on purpose. It was an effort to save money.[2]

A USB that could plug in correctly both ways would have required double the wires and circuits, which would have then doubled the cost. The Intel team led by Bhatt anticipated the user frustration and opted for a rectangular design and a 50-50 chance to plug it in correctly, versus a round connector with less room for error.

Feedback must be Instantaneous:

Paul Pangaro defines Cybernetics as:

Cybernetics is about having a goal and taking action to achieve that goal. Knowing whether you have reached your goal (or at least are getting closer to it) requires “feedback”, a concept that was made rigorous by cybernetics.

Thus, we can see that the device should be designed so that any error must be made visible to the user immediately and the user can correct the error to proceed. Any delay in this can only further add to the confusion of the user. The designer has to take extreme care to reduce the user’s cognitive load, when the user is interfacing with the device. Paraphrasing Michael Jackson (not the singer), from the cybernetics standpoint, the organization of the device should have the best possible model of the environment relevant to its purposes. The organization’s structure and information flows should reflect the nature of that environment so that the organization is responsive to it.

Final Words:

I will finish with wise words from Krippendorff regarding how the user perceives meaning by interfacing with a device.

Unlike what semiotics conceptualizes, from a cybernetic perspective, artifacts do not “carry” meanings from designers to their users. They do not “contain” messages or “represent” meanings…

For example, the meaning of a button is what pressing it sets in motion: ringing an alarm, saving a file or starting a car. The meaning of a soccer ball is the role it plays in a game of soccer and especially what its players can do with it. The meaning of an architectural space is what it encourages its inhabitants to do in it, including how comfortable they feel. The meaning of a chair is the perceived ability to sit on it for a while, stand on it to reach something high up, keep books on it handy, for children to play house by covering it with a blanket, and staple several of them for storage. For its manufacturer, a chair is a product; for its distributor, a problem of getting it to a retailer; for a merchant it means profit; for its user, it may also be a conversation piece, an investment, a way to complete a furniture arrangement, an identity marker, and more.

Typically, artifacts afford many meanings for different people, in different situations, at different times, and in the context of other artifacts. Although someone may consider one meaning more important than another, even by settling on a definition—like a chair in terms of affording sitting on it—it would be odd if an artifact could not afford its associated uses. One can define the meaning of any artifact as the set of anticipated uses as recognized by a particular individual or community of users. One can list these uses and empirically study whether this set is afforded by particular artifacts and how well. Taking the premise of second-order cybernetics seriously and applying the axioms of human-centeredness to designers and users alike calls on designers to conceive of their job not as designing particular products, but to design affordances for users to engage in the interfaces that are meaningful to them, the very interfaces that constitute these users’ conceptions of an artifact, for example, of a chair, a building or a place of work.

Always keep on learning…

In case you missed it, my last post was A Study of “Organizational Closure” and Autopoiesis:

[1] The Cybernetics of Design and the Design of Cybernetics – Klaus Krippendorff

[2] Ever Plugged A USB In Wrong? Of Course You Have. Here’s Why

Tesler’s Law of Conservation of Complexity:

Tesler

In today’s post, I am looking at Tesler’s Law of Conservation of Complexity. Larry Tesler, who came up with the law, worked at Xerox PARC, Apple, Amazon, and Yahoo in different capacities. He was one of the brains behind “cut/copy and paste” functionality in word processors. The basic premise of the law is as follows:

“Every application has an inherent amount of irreducible complexity. The only question is: Who will have to deal with it—the user, the application developer, or the platform developer?”

This is an important idea in the user interaction with a software application. One of the best examples to explain this further comes from Dan Saffer’s excellent book, “Designing for Interaction.” Think of the email application. It needs a “From address” and a “To address”. Without either of these two items, the email cannot be sent. All, if not most, email applications will automatically populate the “From address”, thus not requiring the user to enter it all the time. This “complexity” was addressed by the software application designer. As Dan put it; The complexity isn´t gone, though – instead, some of it has been shifted to the software.

Larry Tesler was a firm believer that the user interaction is almost as important as the application itself.

In the early days of our field, when I worked at Xerox PARC, the idea of user interface consistency was new and controversial. Many of us realized that consistency would benefit not only users, but also developers, because standards could be encapsulated in shared software libraries. We made an economic argument: If we establish standards and encourage consistency, we can reduce time to market and code size.

I postulated that every application must have an inherent amount of irreducible complexity. The only question is who will have to deal with it.

Because computers back then were small, slow and expensive, programs were designed to be compact, not easy to use. The user had to deal with complexity because the programmer couldn’t. But commercial software is written once and used millions of times. If a million users each waste a minute a day dealing with complexity that an engineer could have eliminated in a week by making the software a little more complex, you are penalizing the user to make the engineer’s job easier. (Source: Dan Saffer Interview with Larry Tesler in “Designing for Interaction”)

With this law, we are not trying to make things simple. A complex situation requires that the solution is also complex. This goes back to Ross Ashby’s Requisite Variety principle – “only variety can absorb variety.” The variety is described as the number of possible states of a system. If the “problem” requires that you need 7 states, then the solution should address it by providing at least 7 states. Tesler’s law recommends that we keep this complexity away from the user and absorb it at the programmer’s side. This makes the user interaction favorable leading to a positive user experience. We should focus on making life easy for the user.

The user experience is related to the cognitive load that is placed on the user. The application should try to minimize this load to avoid any potential errors or slips. The more steps a user has to complete, the more likely an error can occur. This may not be a big problem if we are drafting an email, but if the user is a pilot, then the whole scope of the problem changes. Providing a consistent interface and eliminating unnecessary actions minimizes the cognitive load on the user, and ultimately reduces the errors and slips by the user.

This makes me think about the concept of “muri” in Lean. “Muri” refers to the unnecessary burden on the operator or the system. Muri always leads to Muda (waste). When we are designing an interface for the operator at the gemba, we should try to make that interface as user-friendly as possible in order to minimize the cognitive load on the operator. As Tesler’s law suggests, the designer should absorb the complexity so that the operator does not have to worry about it. Many of the concepts of user experience are applicable in designing a work station. The focus is not to make things “simple” but to match the complexity needed and embed it in the interface in an efficient and effective manner so as to reduce cognitive load on the user. This leads to a satisfactory experience for the user and minimizes the chance of errors. When trying to save money, don’t try to cut corners with technology. Think of it from the time saved by the operators and the minimization of cognitive loads leading to better products and processes.

The other side of the coin is an elaboration that Bruce Tognazzini made with Tesler’s law. Bruce is another great User Experience pioneer. He postulated that when we remove the complexity from the user, the user will try to attempt more complex tasks. The reduction in cognitive load on the operator leads to the user engaging in more ideas for improvements that ultimately leads to better and more efficient operator interface. This may also lead to better cross training, and increase in employee morale. There will be more interest in engaging in the improvement culture, which is at the heart of lean.

I will finish with a great Don Norman story about user experience. Don Norman is the director of The Design Lab at University of California, San Diego, and has written numerous books of designing and user experience.

Don Norman is a proponent of designing things so that the conceptual model becomes easy for the user. The conceptual model is the mental model that the user creates when interacting with a designed object. The conceptual model allows the user to understand how the object functions. Don talks about the experience his son had with the first Macintosh computers. At that time, the file storage was mainly done with floppy drives. His son was trying to save a file and got the error message. “Sorry, there is not enough room to save your file.” His son looked at the folder and saw that there were many folders within the folder and they were arranged in a haphazard fashion. His son using the conceptual model he had came up with a solution – rearrange the folder icons in the folder towards the left so that “there was lot more room on the right side.” He tried again saving, and got the same error message. He was puzzled because the folder obviously had more room now. Don stated that his son was using the wrong conceptual model. The “room” on the picture on the folder was not the same as the “room” on the floppy disc.

Always keep on learning…

In case you missed it, my last post was Kufu Eyes: