Prominence & visibility

“You can’t miss it”

■ Design certain elements so they’re more prominent, obvious, memorable or visible than others, to direct users’ attention towards them, making it easier for users to pick up the message intended, or pick the ‘best’ options from a set of choices

■ Simple prominence is one of the most basic design principles for influencing user behaviour, but visibility can also include using transparency strategically as part of a system—drawing users’ attention to elements which would otherwise be hidden

Examples: The most important warning signs should be the most prominent—if a user only has time to take in one message, it should be the one that matters the most (above)

A Dyson vacuum’s transparent chamber makes forgetting to empty it unlikely, thus keeping the effectiveness of the cleaner high and improving user satisfaction (below)

This pattern is about enabling user behaviour: making it easier to make certain choices

Metaphors

“This reminds me of one of those, so I expect
it works that way too”

■ Use design elements from a context the user understands in a new system, to imply how it should be used; make it easy for users to understand a new system in terms they already understand

■ There’s a danger of oversimplification, or misleading users about the consequences of actions, if metaphor use is taken to extremes; it can also trap users in old behaviour patterns

Examples: Everyday software interfaces (above and below left) combine hundreds of metaphors, from the ‘desktop’, ‘folders’ and ‘trash/recycle bin’ themselves to the icons used for graphics functions such as zoom (magnifying glass), eyedropper and so on. Ford’s SmartGauge (below right) uses ‘leaves’ to represent efficiency of a user’s driving style

Metaphors are mainly about enabling user behaviour…
but can also motivate a user to ‘know’ by increasing mindful understanding of how best to use a system.

Perceived affordances

“Looks like you use it this way…”

■ Perceived affordances are what it looks like we can do with something. A button looks like we should push it; a door with a handle looks like we should pull it, whereas a door with a plate looks like we should push it. This is fundamental to interaction design, and in influencing user behaviour, since the actions a design ‘suggests’ to a user will probably be carried out. (There may be hidden affordances too.)

■ Related ideas include mappings – laying out controls so they relate intuitively to the functions they control – and perceived constraints, what users perceive they can’t do with something.

Example: Where a door has a handle, we assume we should pull it. When this isn’t the case, usability suffers!

Implied sequences

“Easy as 1,2,3…”

■ Presenting items in an implied sequence suggests to users that they should be used / experienced in order. Remember that in while in western countries, our reading direction leads us to assume sequences go left-to-right, in other cultures right-to-left may be the norm, e.g. this Hebrew version of the Mozilla browser with right-facing “back” arrow and left-facing “forward” arrow.

■ The sequence of choices can also suggest levels of priority / hierarchy – there’s a small advantage for candidates who are listed first on a ballot paper [PDF]. The order in which options are revealed can also be important, both in terms of what people remember and how they make comparisons

Example: Rows of switches such as these can suggest a sequential form of operation

Possibility trees

“What route should I take?”

■ Possibility trees show users what routes they can follow to achieve a goal, or what results different behaviours can lead to. The way these are presented, via instructions, an interface, or even signage or maps – wayfinding (e.g. these Transport for London studies) – can influence the choices users make. .

■ They can be used strategically: showing users the routes that planners would prefer them to take, or the actions that designers would like users to take.

Example: Once people have become used to using a highly stylised map to plan journeys, such as the London Underground map here, it can affect perceptions of places’ location in real life. For example, Willesden Junction and North Acton stations are a 10-15 minute walk apart, but the distortion introduced by the map suggests that the distance is much further, which in turn can influence the transport choices people make.

Watermarking

“Taking (or showing) ownership”

■ In this context, watermarking means making the ownership (or background) of something evident to users. If people feel they own a device, through some kind of personalisation or acknowledgement that it’s theirs, they will often use it differently to when it seems like it belongs to someone else.

■ One application of this to influencing behaviour is to make it clear or obvious that some shared resources belong to everyone, or to the community, rather than no-one in particular.

Example: A Gloucestershire shopkeeper has taken to writing customers’ names on the packaging of snacks they buy, to encourage them not to litter by ‘taking ownership’ – it has apparently been especially successful with children.

Proximity & similarity

“Those look like they go together”

■ Users will tend to perceive that design elements (buttons, controls etc) which look similar, or are arranged together, will have similar functions or work together as a group (Gestalt proximity and similarity).

■ This can be used strategically to influence user behaviour as a kind of framing technique: group functions that you want users to perceive as going together, or give the controls similar shapes or colours. Likewise, introducing deliberate discontinuity or separation between elements can lead users to treat them very differently.

Example: Bringing light switches together like this allows them all to be switched off at once more easily when leaving a room, but can work against the intuitive mapping linking each switch to the lights it controls.

Colour & contrast

“I simply chose the one that stood out the most”

■ Use colour and visual contrast to influence users’ perceptions and moods, suggest associations between particular behaviours and outcomes, and cause users to notice important elements or information (remembering that colour-blindness affects many millions of users, and so has implications for designers)

■ While some research shows that certain colours can have direct effects on behaviour in certain situations (e.g. the colour of pills), the evidence in general is weaker than is sometimes implied. Nevertheless, clever use of colour can help, support and guide user decision-making and so influence behaviour.

Example: Baker-Miller Pink or “drunk-tank pink” was developed through trials in prisons where painting a cell this colour was found, in certain circumstances, to reduce inmates’ aggression.

Defaults

“What happens if I leave the settings how they are?”

■ Choose ‘good’ default settings and options, since many users will stick with them, and only change them if they feel they really need to (see Rajiv Shah’s work, Thaler & Sunstein and Goldstein at al [PDF article preview] for more detailed examinations of defaults and their impacts)

■ How easy or hard it is to change settings, find other options, and undo mistakes also contributes to user behaviour here

Examples: With most printer installations, the default print quality is usually not ‘Draft’, even though this would save users time, ink and money.
In the UK, organ donation is ‘opt-in’: the default is that your organs will not be donated. In some countries, an ‘opt-out’ system is used, which can lead to higher rates of donation

This pattern is mainly about constraining user behaviour…
but can also enable a user to make the ‘right’ choice.

Interlock

“That doesn’t work unless you do this first”

■ Design the system so users have to perform actions in a certain order, by preventing the next operation until the first is complete: a forcing function

■ Can be irritating or helpful depending on how much it interferes with normal user activity—e.g. seatbelt-ignition interlocks have historically been very unpopular with drivers

Examples: Microwave ovens don’t work until the door is closed (for safety).
Most cash machines don’t dispense cash until you remove your card (so it’s less likely you forget it)
This pattern is mainly about constraining user behaviour.

Lock-in & Lock-out

“This operation cannot be stopped right now”

■ Keep an operation going (lock-in) or prevent one being started (lock-out) – a forcing function

■ Can be helpful (e.g. for safety or improving productivity, such as preventing accidentally cancelling something) or irritating for users (e.g. diverting the user’s attention away from a task, such as unskippable DVD adverts before the movie)

Example: Some websites ‘disable’ right-clicking to try (misguidedly) to prevent visitors saving images.

Extra step

“Are you sure?”

■ Introduce an extra step, either as a confirmation (e.g. an “Are you sure?” dialogue) or a ‘speed-hump’ to slow a process down or prevent accidental errors – another forcing function. Most everyday poka-yokes (“useful landmines”) are examples of this pattern

■ Can be helpful, but if used excessively, users may learn “always click OK”

Example: Train door handles requiring passengers to lower the window

Specialised affordances

“It only fits one way round”

■ Design elements so that they can only be used in particular contexts or arrangements

■ Format lock-in is a subset of this: making elements (parts, files, etc) intentionally incompatible with those from other manufacturers; rarely user-friendly design

Example: The bevelled corner on SIM cards, memory cards and floppy disks ensures that they cannot be inserted the wrong way round

Partial self-correction

“Did you mean…?”

■ Design systems which partially correct errors made by the user, or suggest a different action, but allow the user to undo or ignore the self-correction – e.g. Google’s “Did you mean…?” feature

■ An alternative to full, automatic self-correction (which does not actually influence the user’s behaviour)

Example: eBay self-corrects search terms identified as likely misspellings or typos, but allows users the option to ignore the correction

Portions

“That’s the size it comes in”

■ Use the size of ‘portion’ to influence how much users consume: unit bias means that people will often perceive what they’re provided with as the ‘correct’ amount

■ Can also be used explicitly to control the amount users consume, by only releasing one portion at a time, e.g. with soap dispensers

Example: ‘Portion packs’ for snacks aim to provide customers with the ‘right’ amount of food to eat in one go

Conditional warnings

“It’s warning me I haven’t put my seatbelt on”

■ Detect and provide warning feedback (audible, visual, tactile) if a condition occurs which the user would benefit from fixing (e.g. upgrading a web browser), or if the user has performed actions in a non-ideal order

■ Doesn’t force the user to take action before proceeding, so not as ‘strong’ an errorproofing method as an interlock.

Example: A seatbelt warning light does not force the user to buckle up, unlike a seatbelt-ignition interlock.

Self-monitoring

“How is my behaviour affecting the system?”

■ Give the user feedback on the impact of the way a product is being used, or how well he or she is doing relative to a target or goal

■ Self-monitoring can involve real-time feedback on the consequences of different behaviours, so that the ‘correct’ next step can immediately be taken, but in other contexts, ‘summary’ monitoring may also be useful, such as giving the user a report of behaviour and its efficacy over a certain period. Over time, this can effectively ‘train’ the user into a better understanding of the system

Examples: Energy meters (above) of many kinds allow householders to see which appliances use the most electricity, and how much this is costing, whether or not they choose to act.

GreenPrint, a ‘better print preview’, provides users (and, in an office context, their bosses!) with a summary of the resources it’s helped save, environmentally and financially (below)

This pattern is about enabling user behaviour: making it easier to make certain choices

Kairos

“What’s the best action for me to take right now?”

■ Suggest a behaviour to a user at the ‘opportune’ moment, i.e. when it would be most efficient or the most desirable next step to take

■ Often a system can ‘cue’ the suggested behaviour by reminding the user; suggestions can also help steer users away from incorrect behaviour next time they use the system, even if it’s too late this time

Examples: Automatic warning signs (above) can alert drivers to upcoming dangers at the right point for them to respond and slow down accordingly

Volvo once offered a gearchange suggestion light (below), helping drivers drive more efficiently and save fuel

Kairos can be about enabling user behaviour at exactly the right moment…
but can also motivate a user by increasing mindfulness right before action is taken.

Reduction

“Just one click away…”

■ Simplification of tasks – thoughtful reduction in John Maeda’s terminology – makes it easier for users to follow the intended behaviour.

■ Using ‘shortcuts’ to remove cognitive load from the user (e.g. energy labels) can be very powerful, but be aware of the manipulation potential (see also framing). By removing stages where the user has to think about what he or she’s doing, you may also risk creating exactly the kind of mindless interaction that lies behind many of the problems you may be trying to solve!

Example: The Eco Button reduces the steps needed to put a computer into a low-power state, thus making it much easier for users to save energy.

Tailoring

“It’s like it knows me”

■ Tailor / personalise the information displayed or the way a system responds to individual users’ needs / abilities / situations, to engage users to interact in the intended way

■ Adaptive systems can learn about their users’ habits, preferences, etc and respond accordingly; simpler systems which can ‘detect’ some salient criteria and offer behavioural suggestions could also be effective

Example: The Pam personal activity monitor, by measuring acceleration rather than simply numbers of steps, allows the feedback it gives and exercise régimes it suggests to be tailored to the user, which allows it to be much more like a ‘personal trainer’ than a conventional pedometer.

Tunnelling

“Guide me, O thou great persuader”

■ Guided persuasion: a user ‘agrees’ to be routed through a sequence of pre-specified actions or events; commitment to following the process motivates the user to accept the outcome

■ B.J. Fogg uses the example of people voluntarily hiring personal trainers to guide them through fitness programmes (which also involves tailoring). Many software wizards which go beyond merely simplifying a process, into the area of shaping users’ choices, would also fit in here; there is the potential to lead users into taking actions they wouldn’t do in circumstances outside the tunnel, which must be carefully considered ethically.

Example: The installation wizard for the Foxit PDF Reader tries to get the user to ‘choose’ extra bundled installation options such as making ask.com the default search engine, by presenting them as default parts of the process. By this stage the user cannot exit the tunnel.

Feedback through form

“Look and feel”

■ Use the form of an object itself as a kind of interface, providing the user with feedback on the state of the system, or cues/suggestions of what to do next. It could be visual changes to the form, or haptic (i.e. sensed through touch)

■ This technique is often overlooked in rushing towards high-tech display solutions; can be as simple as something which intentionally deforms when used in a particular manner to give the user feedback, or changes shape to draw attention to the state it’s in

Example: The AWARE Puzzle Switch – designed by Loove Broms and Karin Ehrnberger gives more obvious feedback that a light switch is left on, through obvious ‘disorder’.

Simulation & feedforward

“What would happen if I did this?”

■ Provide a simulation or ‘feedforward’ showing users what consequences particular behaviours will have, compared with others: make cause and effect clearer to users

■ Showing users what will happen if they click ‘here’, or how many miles‘ fuel they have left if they continue driving as they are, tooltips, and even the ‘Preview’ and ‘Undo’ functions of common software, where changes can be easily tried out and then reversed/not applied, can all be considered kinds of feedforward or simulation

Example: Jakob Nielsen suggests that “a financial website could…encourage users to save more for retirement [by showing] a curve of the user’s growing nest egg and a photo of ‘the hotel you can afford to stay at when travelling to Hawaii after you retire’ for different levels of monthly investment”; interactive savings / loan simulators such as this from Yahoo! are increasingly common, and have the potential to influence user behaviour.

Operant conditioning

“Rewards for good behaviour”

■ Operant conditioning means reinforcing or ‘training’ particular user behaviour by rewarding it (or, indeed, punishing it). This could be a system where a user chooses to work towards a target behaviour, being rewarded for every bit of progress towards it, or something which periodically (perhaps unpredictably) rewards continued engagement, thus keeping users interacting (e.g. a fruit machine)

■ Sometimes the reward is a function of the system itself: saving energy naturally results in lower electricity bills. The system must make the user aware of this, though, otherwise a reinforcing effect is less likely to occur.

Example: E.g. Kai’s Power Tools (pioneering visual effects software) revealed ‘bonus functions’ to reward users who developed their skills with particular tools

Respondent conditioning

“Force of habit”

■ Respondent conditioning, also known as classical conditioning, can be applied to influence behaviour through helping users subconsciously associate particular actions with particular stimuli or settings, and responding accordingly: basically, developing habits which become reflexes. If you automatically feel for the light switch when you enter or leave a room, or brake when something appears in front of you on the road, this has effectively become a reflex action.

■ Using design, we could try to associate existing routines with new behaviours we would like – e.g. checking the house’s energy use when we look out of the window to see what the weather’s like outside, by fixing an energy display to the window (a concept by More Assocates / Onzo used this idea). Or we could try to undo these conditioned reflexes where they are damaging in some way to the user, by putting something else in the way.

Example: Smoking is often a conditioned reflex; many devices have been designed to try and undo or thwart this reflex when the user wants to quit, such as the Nicostopper, which stores 10 cigarettes and releases them only at pre-determined intervals.

Computers as social actors

“I like my Mac because it’s so friendly”

■ The media equation is the idea that “media equals real life”, i.e. that many people treat media (computers, TV, other systems) as if they were real people in terms of social interaction. If users believe that a computer (/system) is ‘on their side’, and helping them achieve their goals, it’s probably more likely they’ll follow advice given by the system: you can design systems to use ‘persuasive agents’, whether explicitly using simulated characters (e.g. in games) or by somehow giving the interface a personality.

■ If the system frustrates the user, advice is more likely to be ignored; equally, beware of the uncanny valley. As pervasive computing and artificial intelligence develop, establishing computers as ‘social actors’ in everyday life offers a lot of potential for more ‘persuasive products’.

Example: Microsoft’s Office Assistants, including Clippit / Clippy here, were an attempt to give a helpful personality to Office, but proved unpopular enough with many users that Microsoft phased them out.

Social proof

“What do other users like me do in this situation?”

■ Users will often decide what to do based on what those around them do (the conformity bias), or how popular an option is; make use of this strategically to influence behaviours

■ Social proof works especially well when there is a peer group or users identify with (or aspire to joining) the group against whose behaviour theirs is being compared; an element of competition can be intentionally introduced

Examples: Facebook’s ‘n of your friends added x application’ (above), Amazon’s various recommendation features, and statistics announcing the popularity of a particular website or product, such as the Feedburner ‘chicklet’ here all imply that ‘people like you are doing this, therefore you might want to as well’

Social proof is mainly about motivating user behaviour…
but can also enable a user to ‘know’ what to do, by making it easier to see how others are doing it.

Framing

“Well, if you put it that way…”

■ Present choices to a user in a way that ‘frames’ perceptions and so influences behaviour, e.g. framing energy saving as ‘saving you money’ rather than ‘saving the environment’; categorise functions strategically so that users perceive them as being related

■ An obvious principle to many designers (and politicians, and estate agents); there are many possible framing tactics, such as use of language to give positive / negative associations to options (e.g. ‘sports suspension’ sounds better than ‘hard suspension’). Often used to deceive customers

Examples: Starbucks’ drink sizes—at least on the menu (above)—start with ‘tall’, framing the implied range of sizes much further up the scale, to avoid any negative or mediocre implications that ‘small’ or ‘medium’ might have.

The ‘Knock-off Nigel’ anti-DVD-copying campaign (below) frames crimes against another person, such as theft of money, in the same bracket as downloading a movie, to imply that people who engage in one also engage in the other.

Framing is about motivating people to behave in particular ways.

Reciprocation

“Return the favour”

■ Users often feel obliged to return ‘favours’: design systems which encourage users to trade or share information or resources

■ Can involve ‘guilting’ the user, but best if the user genuinely wants to return a favour

Example: This message from the BitTorrent client Azureus (now Vuze) encourages users to ‘reciprocate’ for having downloaded a file by continuing to seed it

Commitment & consistency

“Stick to the plan”

■ Get users to commit in some way to an idea or goal; they’re then more likely to behave in accordance with this to appear or feel ‘consistent’

■ Can be used less ethically (e.g. the ‘irrational escalation of commitment’ involved in Swoopo)

Example: Voluntarily choosing to have a water meter installed can demonstrate some commitment to reducing water, which may persist as a household tries to remain consistent with the commitment.

Affective engagement

“Getting emotionally involved”

■ Design ‘affective’ products and systems to evoke emotional response as a way of engaging users and influencing attitudes and behaviours

■ Designers have traditionally been very good at manipulating aesthetics to inspire emotional response, but new technologies allow new opportunities, especially with gaming.

Example: Using smiling (or frowning) faces on customers’ electricity bills can increase the emotional response associated with the bill, and lead to (slight) reductions in electricity use. By comparing customers’ use to their neighbours, this strategy also made use of social proof

Authority

“She know’s what she’s doing”

■ Many users will behave as suggested by an ‘authority figure’ or expert even if that behaviour is outside what they would consider normal; systems can be designed to make use of this effect

■ At least three mechanisms at work here: ‘appeal to authority’ in terms of attitude / behaviour guidance, perceived threat to users who ‘disobey’ authoritative messages, and desire to become more like the ‘pros’ by imitation

Example: How much of Twitter’s success at engaging users to join and participate has been due to well-publicised ‘authority’ figures embracing it?

Scarcity

“Not much left, better use it wisely”

■ Whether scarcity is real or not in a situation, if it’s perceived to be, users may value something more, and so alter their behaviour in response: design systems strategically to emphasise the scarcity of a resource

■ Can be down to loss aversion; artificial scarcity can also be introduced (e.g. digital rights management)

Example: Digital fuel gauges showing the remaining range on the current tank can help concentrate drivers’ minds on the scarcity value of the fuel. See also self-monitoring.

Positioning & layout

“I wonder why they laid it out like that”

■ Arrange elements to affect how people use them—it can involve simply positioning elements (functions, buttons, etc) in sequence, hiding elements so they are only available for interaction in that sequence, or designing paths to converge or diverge intentionally

■ The layouts of supermarkets, shopping malls and offices can influence the paths taken by users, exposing them to the shelves, shops and colleagues in a strategic order or hierarchy

Examples: In this service station bathroom (above), the mirrors have been moved from behind the sinks to an intentionally awkward position near the door, so users don’t spend too long in front of them. See this discussion by Meagan Call.

Chicane layouts (below) force drivers to yield priority to oncoming traffic, reducing speeds.

This pattern is mainly about constraining user behaviour…
but can also enable a user by making it easier to use/experience things in the ‘right’ order.

Material properties

“It’s much more comfortable if you use it this way rather than that way”

■ Use materials individually or in combination, chosen for particular properties which influence or affect user behaviour—e.g. comfortable chairs to encourage visitors to sit down, uncomfortable café seating to discourage long stays

■ A change in properties, such as the sudden roughness of rumble strips on the road, can signal to a user that a change in behaviour is appropriate

Examples: Rough-textured paving (above) can act as a subtle barrier
between the cycle and pedestrian tracks: stray over the line on a bike and you’ll feel it.

This bench on the Paris Métro (below) is intentionally too uncomfortable to act as anything other than a very temporary perch: it prevents sleeping or loitering.

This pattern is mainly about constraining user behaviour…
but can also motivate a user, e.g. by ‘rewarding’ certain behaviour with comfort

Segmentation & spacing

“One at a time, please”

■ Break up a system into multiple elements, spaced strategically to influence how a user can interact with them

■ Often used so users can interact with only one element at a time, or to make sure they share a system with others. Removing spacing, or integrating segmented elements, can also be used intentionally

Example: These individual seats replace a bench on the Paris Métro – meaning that someone cannot lie down or occupy more than one.

Orientation

“Slanty design”

■ Use angled elements in a system to influence interaction, e.g. by making it easier or more difficult for some actions to occur than others. Also known as ‘slanty design’ (Russell Beale).

■ Can also be used to ‘funnel’ users, e.g. staggered pedestrian crossings making sure users face oncoming traffic

Example: Sloping lids on cigarette bins to discourage placing of litter on top

Removal

“You can’t use it if it isn’t there”

■ Simply remove system elements or cues which allow or encourage particular behaviours you don’t want to happen, or which would allow a user to proceed without thinking

■ Can also increase the transparency of a system, making it easier for users to see the consequences of their (and others’) actions

Example: The ‘naked roads’/'shared space’ approach of removing road markings and signage to influence more careful driving in urban areas, e.g. here at Seven Dials near Covent Garden in London

Movement & oscillation

“It’s brought right in front of you”

■ Dynamic system elements which move to guide users through a process or present things/functions to users in the order they should experience them – e.g. a conveyor belt in a factory or sushi bar

■ Can also be used to discourage users loitering, or blocking others’ paths, e.g. in a popular museum exhibit

Example: A moving walkway (or an escalator), aside from making it easier for pedestrians to get about, also prevents them blocking the path of others