Designing Interactions For Humans
Did you scroll your social media page today? Did it perform its duty the way you wanted it to? Were you able to scroll up and down, swipe right or left easily? Were you able to forward that funny reel to your friend? You probably did all of these and many more actions today. As you did all of these actions, you basically interacted with your phone screen. The interface of that social media is designed in such a way that your interaction with it is intuitive, pleasurable, and engaging in some manner.
We interact with numerous elements of our immediate environment on a daily basis. Some elements are already present in nature and some are designed by human beings.
Whether you are waking up from the bed, opening your refrigerator to grab some water, flushing your toilet or even reading a newspaper, you are interacting with some element that has already been existent in nature or has been designed by another human or group of human beings.
For man made objects, designing such interaction is a task that requires observation and understanding of how human beings perceive their environment and how their mind works.
One thing is common in every type of interaction. If the experience of the interaction is pleasurable, humans will keep coming back to it repeatedly until it remains so.
In the further discussion below, we will call all the objects made by humans as "Products".
Looking at Interactions on first principles basis
When we interact with any product, we need to figure out answers to three essential questions:
What it does?
How it works?
What kind of operations are possible?
This, in principle, is termed as Discoverability.
Discoverability is driven by five fundamental aspects:
a) What actions are possible?
b) Where does the action should take place?
c) Within what limits the actions should take place?
d) Whether it is easy to figure out how the actions and results are sequenced?
e) Whether there is some way of letting you know that the system is working on your request?
Human beings have fundamentally five senses that are at play while interacting with their environment:
Sight <> Smell <> Taste <> Hear <> Feel
All of these senses come together at play to help us navigate the 5 questions above and provide and overall experience of interaction.
The five questions above are related to fundamental concepts of psychology.
a) What actions are possible? Affordance
b) Where does the action should take place? Signifiers
c) Within what limits the actions should take place? Constraint
d) Whether it is easy to figure out how the actions and results are sequenced? Mappings
e) Whether there is some way of letting you know that the system is working on your request? Feedbacks
Affordance
An affordance is a relationship between the interacting agent (in most of the intended cases, humans) and the object they are interacting with. You can tap on the screen of your phone. You can push a button of a phone to lower the volume or even switch it off. You can carry your cellphone in your trouser pocket. You cannot carry an iPad Pro in the pocket of your regular trouser. You can sit on a chair. You can push the button of a washing machine to start the wash operation. All these examples illustrate what actions ate possible and what actions are not possible. These affordances (what is possible) and anti-affordances (what is not possible) define the first step in the interaction design. These are usually perceivable with our senses. Sometime a direct way of perceiving may not be present and in such cases, some kind of signaling is present to help with the indirect perception.
Signifier
When you push a volume button on your cellphone, it usually takes some time to understand whether the desired action has resulted into the desired result. There are three possibilities. You may operate on the wrong button. You may want to lower the volume but may be pressing on the wrong side of the volume button. Thus a good design of cellphone, provides a good signal of where the action should take place. In order to make the perception visible that your action is resulting into desired outcome, there is usually a slider provided on the display of the phone that moves up or down, or even left or right as you operate on the volume button. The slider itself may be operated directly on the screen. Thus, this signaling helps the interacting agents understand where they should operate on the machine to get the result. Whether they should push the button or can operate on the screen or can choose either of the options. This point will also be touched upon in under "feedback" section below. When you want to take a screenshot on your cellphone, you usually have to press two buttons together.
Mapping
Mapping refers to the relationships between the elements of two sets of things. In simple terms, there is a long set of interactions between various elements that takes place before our action renders desired results. Pushing the pedal in the car moves it forward. Between these two visible actions and desired results, there are a number of interactions that happen within the machine. The compelling conceptual model of how the operations of control affects the vehicle.
When you enter your hotel room, usually there are different buttons for operating different kinds of lights. There are defined buttons on the telephone set in the room that connect you to reception, cafeteria etc.
These mappings are critical to a seamless operation of the devices and to providing desired results.
These mappings are required to be done while keeping in mind the way intended interaction agents (humans in most of the cases) behave.
The more natural a mapping seems, the easier its adoption is.
Feedbacks
When you push a button on your washing machine, there is usually a led light that lets you know that the machine has been switched on and has received the power. It is usually coupled with a beep sound. This is an example of a feedback mechanism that lets you understand whether the system has worked on your request. Similarly, when you push the volume button, the slider on your screen moves down or to the left. Feedback is a communication mechanism that communicates the result of an action. For a feedback to be efficient, it has to have following properties:
It must be immediate
It must be informative
It should not get in the way of other things
It should planned to get activated in appropriate time and manner
For example, when you click on a link over the web, it should ideally immediately take you to desired web address. If you have clicked and the link takes an inordinate amount of time to navigate, you might feel frustrated. If you switch on the power button, and the led light on the machine does not glow, how would you know whether it is receiving power.
We believe that feedback has to be designed by keeping in mind what questions may come to the user's mind once an action has taken place. For example, when the traffic light has turned red, you may want to know when it would turn orange and eventually green. A traffic light signal with a timer in place that people can see clearly is a well designed signal.
Constraints
One of the most powerful tools is design. They limit the set of possible actions. The number of buttons on a cellphone to operate represents a set of constraints. If there are too many buttons beyond an optimized level, the interaction may become unnecessarily complex. Similarly, there should not be more than desired options for doing the same action. Constraints are usually present everywhere because they provide the boundaries within which a device or a system should be able to perform. Right set of physical constraints coupled with the constraints in the user's minds provide a design that is widely acceptable by a large user base.
The Essence
When we interact with various objects there are various psychological factors and senses at play. Designers must take into account these aspects when designing products intended to be used by humans. The products are required to be designed keeping in view the five psychological factors that lead to a memorable experience with the products. Affordance, Signifier, Constraints, Mapping, and Feedback are critical elements of discoverability.
In the future editions, I will delve deeper into these elements. These design elements will be applicable to any kind of design, physical objects, digital interfaces etc.
Key Reference: The Design Of Everyday Things, Don Norman
Cheers
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