All posts filed under “Technology

Exploiting the desire for order

I met a lot of remarkable people in Finland, and some of them – they know who they are – have given me a lot to think about, in a good way, about lots of aspects of life, psychology and its relation to design. Thanks to everyone involved for a fantastic time: I was kind-of aware of the idea of Csíkszentmihályi’s flow before, but something about the combination of week-long permanent sunlight, very little sleep, great hospitality and a hell of a lot of interesting, clever people, brought home to me the reality of the phenomenon, or one quite like it.

A couple of the people it was great to meet were Loove Broms and Magnus BÃ¥ng of the Interactive Institute in Stockholm, who have worked (among other things) on innovative ways to provide users with feedback on their energy use, beyond ‘traditional’ interfaces. We’ve seen a few of the Institute’s STATIC! projects before on the blog before, but it was very interesting to be introduced to some more recent concepts from the AWARE project. They’re all well worth a look, but one in particular intrigues me, primarily because of how simple the idea is:

Puzzle Switch, AWARE project, TII
The Puzzle Switch – designed by Loove Broms and Karin Ehrnberger. One type is shown above; below, a different design in ‘On’ (left) and ‘Off’ (right) positions.Puzzle Switch, AWARE project, TII   Puzzle Switch, AWARE project, TII

The AWARE Puzzle Switchlower part of this page – really is as simple as a a series of light switches where it is very obvious when they are switched on, and which “encourage people to switch off their light, by playing with people’s built-in desire for order.”

Where else can we use this idea? The Puzzle Switch does it safely, in a way that, for example, having a lever hanging off the wall at a crazy angle (which would equally suggest to people that they ‘put it right’) would not. Is the key somehow to make it clearer to users that high-energy usage states are not ‘defaults’ in any way? That accompanying any energy use, there needs to be some kind of visible disorder (as with the irritating flashing standby lights) to cause users to notice and consciously to assess what’s going on?

Lights reminding you to turn things off

Standby indicators - Duncan DrennanStandby indicators - Duncan Drennan

Duncan Drennan
, who writes the very thoughtful Art of Engineering blog, notes something extremely interesting: standby lights, if they’re annoying/visible enough, can actually motivate users to switch the device off properly:

Our DVD player has (to me) the most irritating standby light that I have ever seen on any device. When on, the light is constantly illuminated, but when in standby the light flashes continuously (at a slow rate). This drives me mad, but results in an interesting action — it causes me to turn it off at the plug when I am not using it (which is most of the time). Suddenly one little flashing light has resulted in more energy saving than having no light.

As he notes, designing a system with an indicator which actually draws power to inform you of… ‘nothing’ … actually may not be as inefficient as a from-first-principles efficiency design process would suggest, because of that human reaction. Similarly to the Static! project’s Power-Aware Cord, you may need to use a little extra energy to make people realise how much they’re using without thinking. Although:

There is one problem with this, it only works on people who care. If I did not care about saving energy, then I would just leave the laptop plugged in and the DVD player on. That means that you have to consider how your users will handle this kind of subtle feedback and determine whether turning the light off, or encouraging unplugging, results in more energy savings.

Sometimes the most obvious design decisions may not be the ones which result in the greatest energy saving.

This is a very astute observation indeed.

Are there any other examples where this sort of effect can be usefully employed? How similar is this to the ‘useful landmine’ concept where you deliberately force/provoke/annoy yourself into taking actions you otherwise wouldn’t bother/would forget to do?

Design with Intent presentation from Persuasive 2008

EDIT: I’ve now added the audio! Thanks everyone for the suggestions on how best to do it; the audio is hosted on this site rather than the Internet Archive as the buffering seemed to stall a bit too much. Let me know if you have any problems.

I’ve put my presentation from Persuasive 2008 on SlideShare, – because of the visual style it really needs to be listened to, or viewed alongside the text (below, or in the comments when viewing it on the SlideShare site). Alternatively, just download it [PPT, 11.6 Mb] – it comes with the notes.

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Getting someone to do things in a particular order (Part 3)

Continued from part 2

This series is looking at what design techniques/mechanisms are applicable to guiding a user to follow a process or path, performing actions in a specified sequence. The techniques fall roughly into three ‘approaches’. In this post, I’m going to examine the Poka-yoke approach. If you’ve been following the previous posts, you’ll probably have thought, “Well, all that’s pretty obvious.” And it is obvious – we encounter these kinds of design techniques in products and systems every day – but that’s part of the point of this bit of the research: understanding what’s out there already.

Poka-yoke approach

The mechanisms described in this approach are all based on technical (rather than explicitly human) factors, and involve designing the relationships between system elements.

Poka-yoke (Japanese: mistake-proofing) is an approach usually applied in manufacturing engineering, developed by Shigeo Shingo in the context of developing ‘zero defect’ assembly processes. The idea is to avoid slip-type errors by designing systems which prevent them occurring, prevent a user proceeding until the error condition has been rectified (control poka-yokes), or at the very least clearly warn the user of the error condition (warning poka-yokes).

Generally, when the design intent is for the user to follow a process or path in a specified sequence, a deviation from that sequence can be considered as an error, and thus the poka-yoke approach can be applicable outside its original field. Similar concepts, forcing functions, have been developed in interaction design, especially in the work of Donald Norman – the three main forcing function mechanisms, Interlock, Lock-in and Lock-out, broadly correspond to Shingo’s control poka-yoke category; all can help in assisting (or forcing) users to follow a process or sequence. In the warning poka-yoke category, the Arrangement detection mechanism is most relevant to this behaviour.


An Interlock combines elements of both lock-ins and lock-outs (see below), and is probably the most familiar forcing function mechanism: the ability to use one function is dependent on another running or being started, another component (such as a guard) being in place, or some other condition being fulfilled.

Toyota Verso clutch-ignition interlockToyota Verso clutch-ignition interlockToyota Verso clutch-ignition interlock
Example: This Toyota Verso requires the clutch pedal to be depressed before the starter button will operate, to reduce the risk of starting in gear.

Car ignitions which cannot be operated unless the driver’s seat belt is fastened – a system originally promoted as ‘Interlock’ in the US – microwave ovens not operating unless the door is closed, and airline or train toilets where the lighting does not operate until the user has locked the door, are some of the highest profile everyday examples, but the principle of the interlock is extremely common in engineering and manufacturing industry, often in the context of a machine tool which will not start until a guard is in place, or where opening the case automatically cuts the power.

Interlocks are often specified when it is imperative – rather than merely desirable – that a user follow a particular sequence, or at least two steps of a sequence, in exactly the right order, but their use need not be limited to critical safety design problems. Ecodesign applications might include (for example) a car’s air conditioning system requiring the windows to be fully closed before operating, or a sink requiring the plug to be in before the tap can be left in a ‘running’ position.

Microwave oven door interlockMicrowave oven door interlock
Example: The ubiquitous interlock on a microwave oven ensures that the door is closed before the oven will start.


The Lock-in mechanism in this context (rather than an economic one) refers to a system arranged such that a process, procedure or operation is kept active – the user can’t exit the operation until a certain condition is met, or the ‘correct’ next step is taken. This can be implemented using sensors, logic processing, physical architecture, or a number of other ways.

As Norman puts it, this prevents “someone from prematurely stopping” an operation – this could mean letting some ongoing process run its course to completion before starting the next, or denying the user access to another function which might interfere with the current process. It can also prevent accidental cancelling of an operation – inadvertent deviation from a specified sequence – by introducing an extra ‘confirmation’ step.

Confirmation dialogue
Example: The confirmation dialogue displayed by some software when a user attempts to exit can be seen as a lock-in to prevent inadvertent ending of the application.


Lock-out is closely related to Lock-in: in this case, the mechanism makes it difficult or impossible for the user to start certain operations, or denies or impedes access to particular areas or functions. In the context of encouraging or forcing a user to follow a path or process in a specified sequence, a lock-out helps prevent inadvertent or mistaken steps in that sequence. It can also help prevent an operation being started too early in the sequence, and may also be implemented as an extra ‘confirmation’ step.

Lock-out dialogue
Example: This file backup application prevents a user modifying the properties of a scheduled backup task while it is running – ensuring that the correct sequence is followed.

Arrangement detection

Arrangement detection is a ‘warning’ rather than ‘control’ poka-yoke mechanism, and may be considered as a ‘feedback’ analogue of interlocks, lock-ins and lock-outs – providing a warning (audible, visual, tactile) when system elements are incorrectly arranged (physically or procedurally).

Arrangement detection is about warning the user that the path or process is occurring in an incorrect sequence, rather than actually forcing the user to follow the correct sequence. While there are a number of possible warning poka-yoke mechanisms alerting users to incorrect behaviour, arrangement detection is most relevant to the specific issue of sequencing.

Seatbelt warning
Example: The seat belt warning on car dashboards (in this case a Fiat Punto) is an arrangement detection poka-yoke, providing a visual (and often also audible) alert that a belt is not buckled while the engine is running, or the car is moving.

In part 4, we’ll look at the Persuasive Interface approach to getting someone to do things in a particular order.

Getting someone to do things in a particular order (Part 2)

Continued from part 1

Suggested mechanisms

These are the suggested mechanisms applicable to User follows process or path, performing actions in a specified sequence – they fall roughly into three ‘approaches’. In this post, I’m going to examine the System element approach.

System element approach

This approach includes mechanisms relating to the layout and properties of system elements, hence all technical rather than human factors.

Placing, Spacing and Orientation – how system elements are laid out – are some of the most fundamental mechanisms a designer can employ to help a user to follow a process or path in the intended sequence, and can be used both in the ‘real’ world and, as metaphors, in software. Movement or oscillation, as an ‘action’ property of system elements, which may involve changing their placing/spacing/orientation, can also be used to help achieve similar aims.


Placing may be implemented as simply as arranging interactive elements (functions, buttons, shops, products on shelves – effectively, anything) in sequence so that a user interacts (sees / notices / experiences / uses) them in the ‘right’ order. This might involve actually hiding one element behind another so that the first ‘must’ be dealt with before progressing to the next (or only displaying the second element once the first has been dealt with), but often this is not necessary: users will tend to interact with elements in a predictable sequence, at least where it is clear which direction the sequence is meant to progress (compare reading directions in different alphabets, for example, and the effect this has on the layout of interfaces).

Amazon's order process reveals elements in sequence
Example: The elements of Amazon’s order process, revealed to the user in sequence

Placing can also involve arranging (non-interactive) elements to ‘channel’ users along a path in an intended sequence – walls, fences and guard rails are obvious architectural examples, but there are more subtle ones too, such as the layout of some casinos in which winners are ‘funnelled’ past many lures on their way to a single cashier.

Guard rails to channel pedestrians
Example: Guard rails are placed to channel pedestrians away from crossing at the mouth of a road junction


Spacing – deliberate separation of system elements in space – can also be used strategically to cause users to follow a path or sequence of operations or interactions. For example many supermarkets are laid out with common items such as milk and bread at the back of the store, meaning that shoppers pass many other shelves of items (with potential for impulse purchase) on the way to their ‘target’, and on the way back to the checkouts at the front of the store.

Spacing can also be used to cause users to follow procedures requiring a delay between performing operations – the ‘on’ switch for a lathe may be spaced far enough away from the chuck that it is impossible for the operator’s fingers to be in a dangerous position as the device is switched on. Along similar lines, spacing light switches for different parts of a corridor or stairway apart so that they must each be switched on in sequence individually when needed (rather than allowing users to switch them all on at once) may reduce unnecessary electricity use.

Dairy section drives traffic to rear of supermarket
Example: Dairy items are often positioned to drive traffic to the rear of a supermarket. Image from wander.lust


Orientation is necessarily related to placing and spacing – the relative angle or attitude of system elements can be used as a mechanism for encouraging or channelling users to follow a path or perform actions in sequence. A trivial example is the use of angled walls to ‘funnel’ pedestrians along a particular path. It can also be used to cause users themselves to change their orientation in response, where this is part of an intended sequence of user behaviour – the staggered pedestrian crossings which make sure users turn to face the direction of oncoming traffic, as mentioned in Part 1, use the changing orientation of the walkway to change users’ orientation.

Pedestrian crossing staggered to cause users to face oncoming traffic
Example: A staggered pedestrian crossing designed so that users face oncoming traffic. Image from the UK Highway Code.

Movement or oscillation

Movement or oscillation may involve changing the placing/spacing/orientation of system elements, and can be applied in a physical or metaphorical sense. A moving indicator which guides the user through a process or sequence, or indeed, brings system elements which require interaction to the user (or routes them past), encourages (or forces) following procedures in the ‘right’ order.

Consider this mechanism as a dynamic implementation of placing/spacing/orientation: it has the potential to control much more fully the order in which users are exposed to objects or functions. The most obvious examples are conveyors on production lines, bringing components or products to stationary workers in the right sequence, but even museum exhibits such as the Crown Jewels may be displayed in a rotating or constantly moving case, which displays them to visitors in a certain order and reduces the possibility of undesired interactions.

Conveyor brings items to user in the right sequence
Example: A conveyor (such as this on a Krispy Kreme doughnut preparation line) brings products or components to workers in the right sequence. Image from Silversprite

In part 3, we’ll look at the Poka-yoke approach to getting someone to do things in a particular order.

Getting someone to do things in a particular order (Part 1)

Toggle switches
Photo by trancedmoogle.

Back in January, I introduced the Design with Intent method on the blog. I’ve been developing this since then, and, suitably tested and refined, it should form the first stage of the PhD.

Essentially, the DwI Method is intended to be a structured ‘suggestion engine’, where a target behaviour is put in one end, and a range of applicable mechanisms and design techniques, both physical and psychological, come out of the other. The aim is for it to be useful to designers, engineers, architects, policy-makers, and planners of all sorts, who aim to try and shape or change users’ behaviour in some way – and also useful to users in understanding how their behaviour might be manipulated or shaped, for their benefit or someone else’s, by the products, systems and environments around them.

The post in January looked at some of the different design techniques applicable to the target behaviour ‘No access, use or occupation, in a specific manner, by any user’, through the example of anti-homeless benches, and received some really useful feedback from readers (thanks!), as well as forcing me to think more clearly about how the method is structured. Since then the method has evolved considerably, but it’s not yet in the form I want to publish. However, I thought it would be interesting to share an example of applying the method as it currently stands, to a different target behaviour: getting someone to do things in a particular order.

The target behaviour: Introduction

We want to shape the way a user follows a path or process

Here I’ve identified a target über-behaviour – We want to shape the way a user follows a process or path – which is inherent to many design problems. There are then (at present) three target sub-behaviours, each of which is subtly different, with different design techniques applicable. In this series of posts I’m going to elaborate on User follows process or path, performing actions in a specified sequence.

Often we (designers/planners/engineers/architects) want the user to do things in a certain order, or follow a path, and are aiming to use the design of the system to help achieve that. The process or path can involve simple spatial sequencing (e.g. making sure shoppers walk past certain items on their way to the checkout), software metaphors for physical procedures (e.g. disabling the ‘Next’ button on a software wizard until required options have been confirmed), or a combination of software logic with physical space (e.g. making sure the user removes his or her bank card from an ATM before the cash is dispensed).

This target behaviour also applies to many safety measures: staggered pedestrian crossings which make sure users turn to face the direction of oncoming traffic, microwave ovens which will not start until the door is closed, cars which will not start unless the clutch is depressed or seat-belt buckled, cars where the ignition key cannot be removed until the automatic transmission is in ‘Park’ mode, machine tools which will not start until a guard is in place, and so on.

Ecodesign applications

Possible ecodesign applications may follow similar lines to the safety measures – particularly, increasing the likelihood that operations are performed in the ‘most efficient’ sequence. A kettle that requires users to pre-select the amount of water required before boiling it, for example, such as the Product Creation Eco-Kettle, aims to have users consider how much boiling water they actually need at the ‘right’ point in the sequence – before boiling. A car’s air conditioning system could require the windows to be fully closed before operating. A bathroom sink could require the plug to be in place before the tap could be left in a ‘running’ position.

Interfaces which suggest the ‘most efficient’ action to the user, at the right point (e.g. a rev-counter-linked light on a car dashboard indicating that it’s time to change gear, as formerly used on a number of Volvo models), can also help encourage users to follow the intended sequence of actions.

Applicable mechanisms/techniques

The DwI method suggests a variety of design techniques applicable to this target behaviour, which fall roughly into three ‘approaches’:

Suggested mechanisms

I’ll deal with each of these approaches, with examples of the mechanisms/techniques in action, in the next few posts in this series. Part 2 is up now.