desire lines and affordances.
Photographs by Jan Dirk van der Burg
A Desire Line originally refers to an informal worn path that pedestrians take when deviating from the official sidewalks or set routes, showing where people naturally wish to walk. These “lines� are an expression of where people genuinely want to go, rather where the designer would like them to. However, this idea extends far beyond the design of walkways, being applied to any signs or traces of user activity in an object or environment. Desire Lines embody traces of use or wear that indicate preferred methods of interaction with an object or environment, expressing the ultimate unbiased desire of natural human purpose.
Affordance* refers to a situation where properties or features of an object intuitively imply its functionality and use, allowing people to determine the potential physical actions one could take with it (how the thing could possibly be used). It is the possibility of an action with an object not a property of the object itself. Characteristics and design provide cues which suggest users how to interact with an object. For example, „a button can be pushed; the possibility of pushing a button is its affordance.�
* Term originally coined by a psychologist, James Gibson.
“Affordances provide strong clues to the operations of things. Plates are for pushing. Knobs are for turning. Slots are for inserting things into. Balls are for throwing or bouncing. When affordances are taken advantage of, the user knows what to do just by looking: no picture, label, or instruction needed.� (Norman 1988, p.9)
skateboarding skating affordance.
“Different surfaces and objects in the environment can afford different actions from different people in relation to individual constraints.” Skaters use open spaces which are not designed for the activity of skateboarding, revealing unintended affordances of designed urban environments and inhabiting them in their own way* and just like that different affordances arise from different competencies. Skateboarders don’t use open spaces as they were originally designed but use the urban fabric as they see an affordance to skate. “They are noticing and using aspects of the urban environment, such as steps, walls, curbs and ramps.” (Millie 2009, p.104) They look at the environment in the context of opportunity for tricks.
*skatable urban elements by trasher magazine
87’
Some people perceive skateboarding as dangerous because of the potential for collisions between skaters and other users of a space who are not participants in the activity. Sometimes skateboarding causes damage to the urban fabric. Such damage can include paint stripped of the handrails as well as gouges, skid-marks, scratches and wax deposits being left on walls, benches, steps and other street furniture.
In response to these social and physical concerns about skateboarders use of found civic space a series of social, legal and physical controls have been used to exclude skateboarders from open spaces. Such measures include, the employment of security guards preventing skateboarders from using specific spaces within a city, warning signs prohibiting the activity of skateboarding in particular areas, anti-skateboarding details, sometimes called ‘skate haters’ added onto elements (benches, walls and handrails) in order to make them unusable for skateboarders.* *Spikes and bumps added to handrails, blocks of concrete placed at the foot of banks, chains across ditches and steps.
utility boxes. seating affordance.
comfy?
Even though originally designed to serve as a storage area for electrical devices, utility boxes seem to afford many other functions such those of urban benches, tables and even canvas. Utility boxes appear to be commonly recognized as sit-able objects, due to the height and size of their surface, dimensioned in the way that provides support. In other words, utility boxes match the qualities of a seating device, thus afford seating.
doors. pushing and pulling affordance.
“You have trouble opening doors?” Yes. I push doors that are meant to be pulled, pull doors that should be pushed, and walk into doors that neither pull nor push, but slide. Moreover, I see others having the same troubles — unnecessary troubles.” (Norman 1988, p.1)
The handle has the obvious perceived affordance of graspability and pulling, but as the signs indicate, the door on the right is to be pushed. The design of the door should indicate how to work it without any need for signs, certainly without any need for trial and error. When signs telling you whether to pull or push have to be added to a device as simple as a door, then it’s a bad design. Suppose the door opens by being pushed. The easiest way to indicate this is to have a plate at the spot where the pushing should be done. Flat plates or bars can clearly and unambiguously signify both the proper action and its location, for their affordances constrain the possible actions to that of pushing.
post-boxes. the letter-mailing affordance.
The physical properties of a postbox such as letter-shaped slots provide hints to slip the letter through the opening and affords letter-mailing. But what about the other things that have size and shape similar to the letter? Is there an affordance to get them through the aperture? The slot in the box intuitively implies to throw something through it and the box itself affords storage, but how does one know that it is designed specifically for a letter? Moreover, what about other similar-sized boxes with letter-sized slots, such as litterbins? Do not these also afford the posting of letters, in purely physical terms?
How does one go from the perception of an affordance to understanding the potential action? In this case, through conventions and experience. “The user possesses cultural information relevant to the situation and object in question.” In this case one knows the post-box’s function not from the perception of its physical form alone but because of one’s cultural knowledge about the letter-mailing and postal system.
ashtrays on top of the street bins. learned affordance.
In order to prevent cigarette litter in London, most of the street bins have been equipped with ash trays on top of them. They became so universal that it begun to be a common knowledge that the top surface of a street bin is where one should throw his/her cigarettes. Nevertheless, there are still a few litter bins around the city where ashtrays haven’t been built-in. Even though there are no ashtrays on these bins, people would instinctively put out their cigarettes on top of them because they have already associated this specific surface (top of the bin) with a function (throwing out a cigarette) and it has gained an affordance of an ashtray.
elevator buttons. bad design.
?
There are two buttons in front of every elevator - one and another below it – sometimes they have arrows, sometimes don’t. First of all, how do I learn what is the right thing to do? There are no signifiers giving me any cues. Alright, the buttons afford pushing, but how do I know that the buttons stand for the direction I wish to travel. Assuming that I have already figured out that the buttons represent directions, imagine the following situation. You are on the second floor and you wish to go to the fourth. The elevator is on the third floor and there's an indicator that tells you where it is.* Which button do you press? The right answer is to press up, as this is the direction you want to go. For most people it’s probably an obvious choice but as a kid I intuitively took on another way of thinking. - As the elevator is on the third floor and I am on the second, I want it to come down to me. *Most elevators are accompanied by an indicator showing the waiting person the current floor the elevator is at.
The only way would be to learn through the experience, trials and errors, but since there is no feedback: “some way of letting you know that the system is working on your request.” (From my previous experience I learned that even though I’m sometimes pushing the wrong button the lift always occasionally arrives.) then how do you learn the correct thing about the elevator calling? What is the reason behind letting the user know where is the elevator? Should elevators be equipped with instructions?
automatic faucets. bad design.
When I put my hands under the gesture-controlled faucet expecting to receive water, but it doesn’t turn on, I do not know whether this means that the faucet is broken or that I put my hands in the wrong place*; or that maybe this is a mechanical faucet and I must push, pull, or turn something. Automatic faucets usually lack signifiers and the controls are often invisible, hence their usage might be ambiguous and confusing. Having in mind that the faucet is sensory we wave our hands up and down, hoping to find the precise location where the water turns. * The motion-sensing infrared technology used by most faucets does not read dark colors well. Shiny, reflective surfaces such as stainless steel and glass also confuse the faucets.
The designer assumed that it is intuitive to put our hands where the sensor is, but this assumption appears to be wrong as it is really common for users to not “see� how to use a device and need to guess where to put hands. What is more, automatic sinks don’t have the possibility of changing the temperature as there are no handles. In most cases the water is automatically cold, while most people prefer to wash their hands with warm water.
door lock. intuitive affordance.
When trying to unlock the previously unknown lock I turned the key clockwise (that’s what I learned to be right based on my previous experience with door locks). It is important to mention that this particular lock was located on the left side of the cupboard. I relied my behaviour upon accepted cultural conventions, which along with other cognitive affordances seemed natural and intuitive. “Up’ means ‘more’ and ‘down’ means ‘less’, rotating a knob clockwise affords the perception of increasing the volume or the amount, likewise an anticlockwise direction signifies a lessening or reduction. Upon recognizing the initial failure to unlock the door, I tried an alternative action possibility and turned the key the opposite way what successfully unlocked the doors. “The expectation that the key is to be turned has not changed during this process—only the direction of turning (from clockwise to counter-clockwise)”.
supermarket layout. desire line of a consumer.