Boosting UX design to your benefit.
Thereâs a fine line between an interaction that works and one that is unusable. Interaction design principles help bridge the divide.
Well-executed interaction design plays a huge role in the implementation of great UX, and is indisputably one of the fundamentals of UX design principles.
âUnusableâ means âIâm moving on,â and no matter how âgood lookingâ the visual designâhow fancy that animation isâmess up the interaction design and your UX is kaput. Get it right and youâll be well on your way to a much better UX even if the aesthetics fall short. The product will have a much better chance of succeeding, which in turn contributes to the bottom line.
Interaction design (IxD) is defined by the Interaction Design Association (IxDA) as âthe structure and behavior of interactive systems. Interaction designers strive to create meaningful relationships between people and the products and services they use, from computers to mobile devices to appliances and beyond.â
âExperience is critical, for it determines how fondly people remember their interactions.â âDon Norman in The Design of Everyday Things.
Following interaction design principles contributes immensely to great interaction design, which in turn will contribute to the experience.
Itâs possible that all of todayâs devices and tech could be replaced with something entirely different overnight, yet because of its lasting principles, great interaction design would still be achievable. Those constant principles are about what motivates people, their behavior, and how they think.
Imagine if every door handle on every door worked differently. For one you would have to push first into the door then down; for another youâd have to pull up instead of pressing down, and yet another youâd have to pull up twice and then downâa total disaster. In fact, the phrase âturn the door handleâ assumes there is only one way to do it.
Nobody likes being beaten over the head by cries of âfollow the rules,â but truly excellent interaction design relies on a set of standards, best practices, conventions, and rules of thumb (heuristics). Itâs no squishy science, but they form the bedrock of IxD and make interaction possible with the least amount of friction. Interface standards donât stifle creativityâthey are not hard and fast rules, but foundational guidelines that help a designer establish a âusable and familiar designâ base from which to innovate.
Interaction Design Principles and Best Practices
Great UI design achieves pure user delight by combining basic UI design principles with goal-driven interaction design.
Successful interaction design employs simple, clearly defined goals, a strong purpose, and an intuitive UI.
In an effort to keep interactions simple and easy, goal-driven interaction design puts nothing more than the absolute minimum necessary in front of users in order for them to complete a task.
Letâs dive into some of the most important principles (not an exhaustive list by any means)
Basically, if the user cannot find it, it does not exist. It must be made clear as a bell what actions are possible in a UI in less than a microsecondâfor example, labeling icons as a best practice. Unlabeled icons are tantamount to throwing roadblocks into a userâs path because theyâll have to stop to decipher meaning. Youâre interrupting the âflow.â And hereâs a shocker⌠Theyâre not interested in learning your UI.
Very much tied to discoverability, effective use of signifiers ensures that affordancesâthe possibility of an action on an objectâare clearly indicated in the UI. Signifiers provide strong clues like signals or signposts. Indicating an available interaction, they flash green lights at the user shouting, âHere I am, you can tap (click, swipe, etc.) me!â An affordance may exist in the UI, but may stay hidden because if it lacks a signifier, it remains invisible. An example might be a âhidden gestural interactionâ that doesnât reveal itself unless the user accidentally swipes left or right (to delete something, for example).
âAffordances define what actions are possible. Signifiers specify how people discover those possibilities: signifiers are signs, perceptible signals of what can be done. Signifiers are of far more importance to designers than are affordances.â âDon Norman (Norman, 2013)
After signifiers, the next most important communication to the user is feedback. Feedback means: explicit information about the impact of the action. It also means constant visibility of system status, i.e., the system should make sure that:
Users are kept informed about whatâs going on.
There is continuous information about the results of their actions and the current state of the product (system).
There is no confusion in the mind of a user as to the state of the product, i.e., processing, loading, searching, uploading, etc., or some other state change.
After an action has been executed, itâs easy to determine the new state.
Conceptual Models and Mental Models
Great interaction design presents all the information a user needs to create a good conceptual model of the system, thereby leading to their understanding and a sense of control. A conceptual model enhances both discoverability and evaluation of results when using the system.
Mental modelsâor cognitive mapsâare the images in a userâs mind that inform their expectation of a certain interaction and how something works in the real world. Cognitive maps are internal representations of our physical environment, particularly associated with spatial relationships. By effectively using the userâs mental model, interaction designers can create systems that âfeelâ intuitive.
The designer invents a conceptual modelâthe design model, and this is how the designer intends the device or software to work. The only way to communicate this model to users is to implement it through a UI. Users then interact with the conceptual model and create their own mental model of how something works.
Designers canât tell users how they intended an app to workâthey need to design a UI appropriately in order to clearly communicate its purpose. In other words, make the interface easy to understand and use. Bad interaction design runs the risk of creating the wrong mental model for the user. This leads to confusion and user error because they are trying to operate the app in a way the designer did not intend.
Mapping is the relationship between controls and their effect in the world. The principle of feedback is a close cousin of mapping because the two principles work together to create a seamless experience. Nearly all artifacts need some kind of mapping between controls and effectsâin the case of interface design, itâs the relationship between a control and its resulting function. Natural mappingâtaking advantage of physical analogies and cultural standardsâleads to an immediate understanding. For example, a designer can use spatial analogy in the UI:To increase some value with a slider component, swipe a slider to the right,To decrease it, swipe left.Some natural mappings are biological, as in the universal standard that a rising level represents more, a diminishing level, less.
The design concept of constraints is a way to determine how to restrict the kind of user interaction that can take place in a given moment. Interaction design constraints help efficient interaction by providing âguide railsâ for usersâalmost like a guiding hand steering the interactions that can occur.
Constraints in design make sure only specific things are enabled, or even visible, in order to guide the user towards certain interactions. It considers size, scale, proportion, emphasis, and state, and how these, working together in harmony, help create hierarchy and consequently influence the user. Constraints put in place correctly also help reduce the chance of user error.
The opposite of constraint is when every option is offered to the user, making it difficult for them to decide what to do next. Itâs the principle of choice. The more options, the more difficult it is to choose any one of themâwe become overwhelmed by all the possibilities.
Great interaction design doesnât put every available option on the interface, but restricts it to whatâs most important in any given moment.
Consistency, Standards, and Heuristics
These are all relatedâbrothers to patterns (below), if you will. To prevent user error and make an application easy to learn, it is essential that an interaction model be consistent. Consistency improves UX, general usability, and the efficiency with which users can use digital products.
Consistency means using similar elements to achieve similar tasks, and having similar functions and behaviors throughoutâa consistent interface is one that follows rules, such as using the same operation to do something. Products that strive to be highly usable follow well-established conventions, standards, best practices and usability heuristics (broad rules of thumb, not specific usability guidelines).Conforming to a convention for example, may be in the way a page is laid out. Web users spend 69% of their time viewing the left half of the page and 30% viewing the right half. Therefore, a site is more likely to be profitable if it follows a conventional layout.A standard could be a breadcrumb trail (an orientation and navigation device thatâs immediately recognizable), or a global navigation menu across the top of the page as on the BCC site.
Patterns and Learnability
How easily can a new user learn to navigate an interface? Nobody wants to learn a new way of doing things unless it provides a significant benefit over what came before itâyet weâre constantly inundated with untested, unconventional interactions.
Common components or patterns provide instant learnability. Once youâve learned how to use a spoon, you will always know how to use a spoon. Same with riding a bicycle, skating⌠the same construct applies to the UI components we use every day: buttons, text fields, dropdown menus, checkboxes, radio buttons, spinners, sliders, icons, accordions, search boxes, etc.
The best interaction designs donât try to reinvent the wheel, but make efficient and effective use of patterns in a new way.
Patterns not only encourage learnability, but also provide consistency (another principle, discussed above) and bring it in line with the userâs expectations of how things should work.
Visual Hierarchy and Emphasis
During their interaction with a site or an app, people are looking for the information most relevant to their search. Visual hierarchy concerns the arrangement of elements in a way that implies importance. Visual hierarchy in design influences the order in which the human eye perceives what it sees. Not everything is given equal âweightâ; order is created by visual contrast between objects in a field of perception. Visual contrast (emphasis) can be achieved by size, proximity, color, opacity, and actual tonal contrast between elements.
Do not underestimate the power of visual hierarchy. Itâs been very effectively used in all kinds of design for eons, in architecture and industrial design as well as print design. Check out some great poster designs. Using this technique well in interaction design, the right things seem to appear at the right time in the right way.
Great interaction designers use the power of emphasis to successfully achieve âlean and meanâ interface designs that seem to work like magic.
Believe it or not, this law comes from early studies looking at human muscle movement and targeting of telegraph operator and production line task performance, and was later adapted to HCI (human-computer interaction). It basically says: âThe time to acquire a target is a function of the distance to and size of the target.â
In simpler terms, itâs about how far and how large a target is, and how close it is in relation to other targets. Shorter mouse movements or taps are betterâit is always faster to click or swipe a target if it is closer to your starting position. Related tasks should also be in close proximity to each other so users donât have to dart around the screen interacting with the UI.
Fittsâ law can accurately predict the amount of time it takes to move to and select a target. A target can be a button, a dropdown, or some other interactive element on a screen. If itâs too far, too small, or if clickable elements are too close together, the efficiency and usability of the UI is greatly reduced.
Gutenberg Diagram, Z- and F-Pattern Layouts
These patterns are applicable in different situations depending on content, and are mostly used by western audiences. The Gutenberg diagram describes a general pattern that the eyes move through when looking at evenly distributed, homogenous informationâmostly text-heavy sites such as blogs or news sites. The Gutenberg diagram suggests that the strong and weak fallow areas fall outside the reading gravity path, and receive minimal attention unless emphasized visually in some way.
The Z-pattern follows the shape of the letter Z. In certain cases this pattern is also referred to as a Zig-Zag pattern. The main difference with the Gutenberg diagram is that the Z-pattern suggests viewers will pass through the two fallow areas. Otherwise they still start and end in the same places, and still pass through the middle. As with Gutenberg, a designer would place the most important information along the Z-patternâs path.
F is for fast and refers to how users read content. The F-pattern was popularized by an NNGroup eyetracking study which recorded more than 200 users reading content on the web. It found that peopleâs scanning patterns were pretty consistent across many different types of sites.
Why is this important? On an eCommerce site for example, to maximize scanning, you might want to arrange the most important content in a way that follows the F-pattern.
Recognition Rather than Recall
Recognition refers to our ability to ârecognizeâ an event or piece of information as being familiar, while recall is much more of a âcognitive burdenâ that involves pulling related details from memory. Showing users things they can recognize improves usability over needing to recall items from scratch.
For example, using icons in a UI is powerful because it allows for the instant recognition of a symbol. Our brain processes (recognizes) symbols about 1000x faster than reading text. If a designer displays a standard warning sign icon in a dialog, it immediately makes the user focus and pay attention because the next action may be destructive. But if an icon is designed in such a way that forces users to recall and decipher meaningâa hand held up for example instead of the warning iconâit decreases efficiency and the usability of the UI.
Aesthetic and Minimalist Design
âYou have to deeply understand the essence of a product in order to be able to get rid of the parts that are not essential.â âJonathan Ive.
This is one of the most challenging principles because itâs hard. The tendency is for designers and product managers to add every available option under the sun, and let the user decide the path they want to take. Thatâs really the lazy approach, and leads to products full of nonessential clutter.
Interfaces need to be cleared of the unnecessary elements and content that does not support the userâs goals and tasks. Designers should not only design aesthetically pleasing UIs, but also prioritize information screen-to-screen in the user flow. Using visual hierarchy and the magic of emphasis, only the essential and absolute minimum of information needed for the user to complete a task should be presented.
Michelangelo said of his work: âI saw the angel in the marble and carved until I set him free.â
Designing an interaction that is minimalist, aesthetically pleasing, and simple requires the designer to understand whatâs going on precisely in the moment people will be using the product, and get rid of all thatâs not necessary. Performing deep user research and testing to understand how users will use the product is typically the best approach.
Users are often distracted when performing a task, so preventing unconscious errors by visual emphasis, offering suggestions and the use of carefully designed constraints is key. A form of error-proofingâalso known as Poka-Yokeârefers to the implementation of failsafe mechanisms to prevent a process from producing errors.
One of the best ways to prevent errors is to design a better mental model. Many user mistakes occur when the designerâs model and interpretation of how the system should work does not match the userâs mental model.
Standard design conventions help (one of the principles mentioned above) because they help users understand what actions they can take. Users that interact with your website or application have used thousands of other sites and apps, and expect common interactive elements to look and work a certain way. Error-prone situations can arise when your product deviates from those conventions.
The Future of Interaction Design
New devices, environments, and interfaces will continue to advance with new interaction possibilities. Video-game controllers are constantly evolving, and provide a diverse array of input controls, as well as haptic feedback. Gestural interfaces will mature from touchscreens that support 2D and 3D gesturesâfor example, gestures on iOS and Android devicesâto using hand gestures in 3D spaces to interact with virtual-reality spaces, gaming consoles, and IoT devices that let us control our environment.
As in the case of Googleâs Project Soli, we may say sayonara to the mouse, trackpads, and joysticks, and switch to more natural gestural interactions using our hand and fingers to control devices. In certain instancesâin conversational UIs for exampleâinput methods may change from keyboard to voice. Nevertheless, the principle of immediate and continuous feedback in some form (voice, haptic and visual) will still be needed. Fundamental interaction design principles will always play a central role in the design of future systems and itâs important for UX/UI designers to keep them in mind. Theyâre not hard and fast rules, but will make for better and more engaging products and services. Just as successful movies use ancient storytelling techniques that follow a tried and true, time-honored structure, there are interaction design principles that exist for a good reason. Following them will benefit any product designer by improving usability and driving wider adoption of their products.