“Design is not just what it looks like and
feels like Design is how it works.” This famous
quote from Steve Job stresses the importance of having good interaction design
– the user’s overall experience and satisfaction with a product.
And no company embodies this better than Apple. But what exactly is HCI and interaction design? Is it the same as UX? And what do interaction designers do anyway? Read on to find the answers to these questions and learn more about interaction design.
What is interaction design?
Interaction design, often abbreviated as IxD, is the practice of designing interactive digital products and services. John Kolko, Author of Thoughts on Interaction Design, gives the following definition to interaction design: “Interaction Design is the creation of a dialogue between a person and a product, system, or service. This dialogue is both physical and emotional in nature and is manifested in the interplay between form, function, and technology as experienced over time.”
Interaction designers focus on the way
users interact with products and they use principles of good communication to
create desired user experiences.
Interaction design and user experience
The term “interaction design” is sometimes
used interchangeably with “user experience design.” That’s understandable
because there’s a huge overlap between interaction design and UX design. After
all, UX design is about shaping the experience of using a product, and a major
part of that experience involves interaction between the user and the product.
But interaction design and user experience aren’t synonymous.
The key difference between UX and
interaction design is in the way we think about user interactions. Interaction
designers are focused on the moment when a user interacts with a product and
their goal is to improve the interactive experience. For UX designers, the
moment of interaction is just a part of the journey that a user goes through
when they interact with a product. User experience design accounts for all
user-facing aspects of a product or system.
UX design and
interaction design are connected but it’s nearly impossible to create good
interaction design in isolation of UX. Interaction design is a spoke in the
umbrella of user experience (UX design).
The five dimensions framework
The five dimensions of interaction design is a useful model for understanding what interaction design involves. Gillian Crampton Smith, an interaction design academic, first introduced the concept of four dimensions of an interaction design language. Kevin Silver later extended his model with the fifth dimension.
IxD involves words (1D), visual representations (2D), physical
objects/space (3D), time (4D),
and behavior (5D).
- 1D: Words. Words encompass text, which helps convey the right amount of information to users. Words, especially those used in interactions, like button labels, should be meaningful and simple to understand. They should communicate information to users without overwhelming them with too many details.
- 2D: Visual representations. Visual representations include typography, icons, and other graphics with which users interact. Visual representations usually supplement the words used to communicate information to users.
- 3D: Physical objects or space. Physical objects are a medium through which users interact with the product or service. For instance, a user interacts with computers and a mouse while sitting on a desk in an office space.
- 4D: Time. Time helps users understand visual changes in a UI; it also helps users track their progress.
- 5D: Behavior. Behavior includes both action and reaction. Behavior is what describes the mechanism of an interaction with a product.
Interaction designers should utilize all
five dimensions to consider the interactions between a user and a product in a
Interaction design principles
While it’s impossible to list all of the
principles of interaction design, it’s still
possible to describe a few general areas that are widely used in this field:
Goal-driven design is a design style that
holds problem-solving as the highest priority. This
approach focuses on satisfying the specific needs and desires of a person who
will use the product, which is the goal of interaction design.
Usability answers the question “can
people use this product?” Good usability is a fundamental requirement for
interaction design. Learnability (how easily can a new user learn to use the
interface?), efficiency (how quickly can users perform tasks?), error rate (how
many errors do users make while interacting with UI?) as well as error-recovery
(how quickly can they recover from errors?) are four things that have a direct
impact on usability.
It’s possible to measure usability using
task-completion time and overall satisfaction (do users enjoy using the
When it comes to actual design decisions,
interaction designers often familiarize themselves with the user’s mental model
– the perception or representation that a person
has in his mind of the product she is interacting with. The knowledge
they gain from the mental models helps them create systems that feel intuitive.
Interaction designers apply physiological
principles to the design of products. The goal of this process is to reduce
human error, increase productivity, and enhance the safety of interaction.
Interaction designers often use a predictive model of human movement, also
known as Fitts’s law, when they design interactions. This law says that the
time required to rapidly move to a target area is a function of the ratio
between the distance to the target and the width of the target. Fitts’s law is
used to model the act of pointing. It can be applied both when the UI element
is touched with a hand or finger, or virtually, using a pointing device.
Positive emotional responses
Designers must create a design that
influences positive emotional responses in users. Interaction designers are
aware of elements that influence user emotional responses. Color palettes,
fonts, animations—all of them can trigger
Design for people
When it comes to product design, it’s hard
to design for an abstract user. Designers should always evaluate their decision
in the context of a particular user group. Personas
are a great tool for designers.
A persona encapsulates critical data about
a user group in a way that designers can understand and relate to. The
emotional aspects influence designers to create better product behavior.
How do designers
address interaction problems? They use patterns. A pattern is a solution for a
particular context. In many situations, designers can address new problems
through the modification of existing patterns. The goal of interaction design
is to create a solution that fits well in the context of use.
Usually, interaction designers start with well-known interface guidelines such as Human Interface Guidelines by Apple and Material Design by Google. The guidelines not only provide the patterns that are familiar for the users but also show how to use them in specific contexts.
Designers can have multiple solutions for
one particular interaction problem. The only correct way to reduce the number
of design options is to see how it works for real users (validate it through
testing). Not all assumptions about interaction design pass the testing. Quite
often, designers have to return to the drawing board to design an alternative
solution. That’s why interaction design is rarely linear, but an iterative
Role of an interaction designer
After resting all the information, you
might still wonder, “What do interaction designers really do?” There is no
single correct answer to this question. As a separate role, “interaction
designer” exists primarily in large organizations such as Google and Apple, but in smaller organizations, the responsibilities
of an interaction designer are distributed between UI and UX designers.
Generally, the responsibilities of the
interaction designer include identifying key interactions of the product and
creating prototypes to test concepts. Here are two areas where the impact of
interaction designers is especially significant:
- Design strategy. The interaction designer always starts with understanding what the target user is trying to accomplish (their goals) and finding interactions that will help to achieve those goals. Interaction designers might have to conduct user research to find out those goals.
- Prototyping. Interaction designers often create interactive prototypes to lay out the interactions. Sometimes, in order to make the interaction obvious for the user, interaction designers create interactive prototypes that look exactly like the actual products.
Interaction designers work together with
other designers (UX and visual designers) to ensure
that all interaction patterns are implemented correctly in a product.
Interaction designers should always be on top of the current technological
trends and always measure them in the context of value they deliver to users.
Best practices for designing interactions
Usability.gov suggests asking the following questions when creating digital products that have an interactive element:
- What commands can a user give
to interact with the interface?
- What about the appearance
(color, shape, size, etc) gives the user a clue about how it may function?
- What information do you provide
to let a user know what will happen before they perform an action?
- Are there constraints put in
place to help prevent errors?
- Do error messages provide a way
for the user to correct the problem or explain why the error occurred?
- What feedback does a user get
once an action is performed?
- How long between an action and
a product’s response time?
- Are the interface elements a
reasonable size to interact with?
- Are edges and corners
strategically being used to locate interactive elements like menus?
- Is information chunked into a
few items at a time?
- Are familiar formats used?
Digital design is a conversation. This
conversation happens between a machine and a person who uses it. When people
interact with a product, they love having smooth interactions, but it only
happens when interaction designers make things right.