Take a moment and look around. Are you inside? Then you might come across books, a pile of mail, your computer and television. Or maybe you're outside, carrying your mobile device, and checking your appointments. The world we live in is surrounded by ubiquitous information. Information that is visual, audible, and tactile. It it meant to inform, to entertain, to instruct, and to warn. Because we are constantly bombarded with this information in our daily lives, we must quickly collect, filter, store, and process which of it is important to use for specific tasks.

Consider a busy intersection you are trying to cross. You are surrounded by the sights and sounds of pedestrians conversing, cars and trucks honking, birds flying, signage on billboards, and thousands of other types of stimuli. Our minds have an amazing ability to focus on the task at hand, filter the surrounding "noise," process, store, and allow us to act on only the relevant information.

When the crosswalk signal changes to "Walk," we identify the sign, interpret it's meaning, determine an action to move our body forward, carry out our actions by walking until you've crossed the street achieving your goal.

Understanding how we process and filter visual information, or data, will help us design effective displays of information on mobile devices. Let’s first explore the types of information.

Types of Visual Information

All humans have more or less have the same visual processing system. However, without a standardized way of explaining and notating our perceptions, our communication of this information becomes arbitrary and not effective when designing mobile interactions.

Bertin (1977) organized visual information into two forms: data values and data forms. Ware (2000) introduces a more modern way of dividing data into entities and relationships.

Entities are the objects that can be visualized such as people, buildings, signs. Relationships (sometimes called "relations"), define the structures and patterns that entities share with each other. Relationships can be structural and physical, conceptual, causal, and temporal.

These entities and relationships can be further described using attributes. These are properties of both the entity and the relationship, and cannot be considered independently. Some examples of attributes are:

• Color.
• Duration.
• Texture.
• Weight, or thickness of a line.
• Type size.

For each of these we mean the attribute as it applies to a specific item. Not texture in general, or the texture of paper, but the texture of a specific type of paper (or even, a specific sheet of paper).

Classifying Information

In addition to creating descriptions of our perceptions, we have also standardized a classifying way to organize them. Common classifying schemes that we use are:

• Nominal - uses labels and names to categorize data.

• Ordinal - using numbers to order things in sequence.

• Ratio - a fixed relationship between one object compared to another using a zero value as a reference.

• Interval - the gap between two data values is measurable.

• Alphabetical - using the order of the alphabet to organize nominal data.

• Geographical - using location, such as city, state, country, to organize data.

• Topical - organizing data by topic or subject.

• Task - organizing data based on processes, tasks, functions and goals.

• Audience - organizing data by user type, such as interests, demographics, knowledge and experience levels, needs and goals.

• Social - a collaboration of organizing data by users who share the same interests. Such as tagging, adding to a wiki, and creating and following twitter feeds.

• Metaphor - organizing data based on a familiar mental model to the user. Such as organizing computer files with folders, trash, and recycle bin.

Organizing With Information Architecture

Now that we are able to describe the data that we perceive, we must understand how this information should be structured, organized, labeled, and identified on mobile user interfaces.

One of the most common organization structures humans have used through time is a hierarchy. A hierarchy organizes information based on divisions and parent-child relationships. When using heirarchies to organize information, Peter Morville explains rules to consider (Morville, 2006): Categories should be mutually exclusive to limit ambiguity. Consider the balance between breadth and depth. When determining the number of categories regarding breath, you must consider the user's ability to visually scan the page as well as the amount of real estate on the screen. When considering depth, limit the scope to two to three levels down. Recognize the danger of providing users with too many options.

Another way to organize information is faceting. In this, there are no parent-child relationships, just information attributes, like tags, which may be sorted or filtered to display the most appropriate information. The tags do not have to be explicit, and faceting may be accomplished by searching text descriptions, or even unusual methods such as searching for shapes, patterns or colors directly within images.

Of course, these two methods, hierarchy and faceting may be used in conjunction. A hierarchically-ordered data set can also have tags attached to it, and the facet view may combine both strict and arbitrarily ordering to display the information the user wants.

Date and location are essentially special cases, and depending on the data or needs may be approached either way, even though they are strictly defined. For example, location can be an arbitrary value, with filtering or sorting for distance around a single point. Or it may be considered as a heirarchy of continent > nation > state > county > city > address.

List Navigation

A key tactical consideration, mentioned several times in the patterns, is whether browsable data sets are circular or dead end. Circular lists simply go around and around. When at the "last" item in a list, continuing to view the next item will display the first one in the list. This is useful for faceted views, or other cases where the ordering is unimportant.

For dead end lists, there is a definitive start and stop, and (aside from links such as "back to top") there is no way to go to the other end. These are useful for information with a very ordered, single-axis display. Most hierarchies, and much date-sorted information should display like this. Such as a message list that starts with the most recent. For clarity, above the most recent message is nothing (or controls to make a new message), not the oldest message.

Very often, the manner of the data must be combined with the appropriateness of a solution to select the pattern. Carousels, for example, work best when circular, and Grids work well as dead ends.

Additional details of list navigation are detailed under the appropriate Widget section.

Developing an Information Architecture

Actually developing the information architecture of the product, service or even a single display is a lengthy process, outside the scope of this book. Among other things, it very often will have to work within technical constraints, or legacy (even third-party) data repositories or business practices.

If you have a chance to perform user research, and develop a model informed by the principles above, and actual needs then by all means do so. What you are seeking from this is the true needs and expectations of users. Note, there are three types of knowledge that the users have in their head, and a lot of the methods you may encounter (e.g. focus groups) at best only gather from one of these segments. All have to be considered.

Explicit

Explicit knowledge can be easily described. It is knowledge that can be written down, spoken, and shared. Naming all 50 US states, writing down the lyrics of your favorite song, or explaining how to use Google Maps are all examples of explicit knowledge. This sort of knowledge is easily accessed and is on the highest cognitive level. This is knowledge that describes current and past experiences, but lacks a connection to future experiences like dreams, aspirations, and fears. Some methods you can use to access people's explicit knowledge are:

• Interviews.
• Storytelling.
• Explaining directions or procedures.
• Documenting in a journal, with photos, or other methods.

Observable Knowledge

Observable knowledge can be shown by action and procedure. Drawing a map of all 50 states, putting together a jigsaw puzzle or playing a favorite song are examples of observable knowledge. This level of knowledge is easily accessed, and is stored at a deeper cognitive level. This knowledge will describe current and past experiences, but lacks a connection to future experiences like dreams, aspirations, and fears. Some methods you can use to access people's observable knowledge are listed below.

• Mental model drawings.
• Acting out behaviors.
• Using objects, or services, in context.

Tacit Knowledge

Tacit knowledge is not easily shared or written down. It is the knowledge of discovery and creation. It stems from our desire to know more, to create something new, original, playful, challenging, and satisfying. Tacit knowledge is deeply embedded within our cognition. Examples of tacit knowledge are creating an abstract painting, sculpting pieces of clay into a vase, navigating yourself through an unknown city, and swimming the freestyle. The following methods can be used to generate tacit knowledge:

• Collaging
• Co-Discovery
• Model Making

User's behaviors and beliefs can be quite different from each others, and from your point of view, from the inside of a system. To understand why, we needed to understand that our experiences and perceptions are embedded within different knowledge levels. These knowledge levels can be easily and quickly recalled, or deeply embedded and latent, where methods of discovery and creation are needed to access them.

Once you have gathered and analyzed information like this, you can use generate user needs, rank them in importance, and group them into categories. This will rapidly become a usable information architecture. Conflicts with technical systems are usually smaller than you'd expect, and can easily be mitigated by carefully comparing the ideal, user-centered diagrams and the true technical requirements.

Visual Perception

After our senses collect visual information, our brain begins to perceive and store the information. Perception involves taking information that was delivered from our senses and interacting it with our prior knowledge stored in memory. This process allows us to relate new experiences with old experiences. During this process of visualization of perception, our minds look to identify familiar patterns. Recognizing patterns is the essential for object perception. Once we have identified an object, it is much easier to identify the same object on a subsequent appearance anywhere in the visual field (Biederman and Cooper, 1992).

The Gestalt School of Psychology was founded in 1912 to study how humans perceive form. The Gestalt principles they developed can help designers create visual displays based on the way our minds perceive objects. These principles, as they apply to mobile interactive design are:

• Proximity - Objects that are close together are perceived as being related and grouped together. When designing graphical displays, having descriptive text close to an image will cause the viewer to relate the two objects together. This can be very effective when dual coding graphical icons.

• Similarity - Objects sharing attributes are perceived to be related, and will be grouped by the user. Navigation tabs that are similar in size, shape, and color, will be perceived as a related group by the viewer.

• Continuity Smooth, continuous objects imply they are connected. When designing links with nodes or arrows pointing to another object, viewers will have an easier time establishing a connected relationship if the lines are smooth and continuous and less jagged.

• Symmetry - Symmetrical relationships between objects imply relationships. Objects that are reflected symmetrically across an axis, are perceived as forming a visual whole. This can be bad more easily than good. If a visual design grid is too strict, unrelated items may be perceived as related, adding confusion.

• Closure - A closed entity is perceived as an object. We have a tendency to close contours that have gaps in them. We also perceive closed contours as having two distinct portions: an inside and outside. When designing list patterns, like the grid pattern described in this chapter, use closure principles to contain either an image or label.

• Relative Size - Smaller components within a pattern are perceived as objects. When designing lists, using entities like bullets, arrows, nodes inside a group of information, will be viewed as individual objects that our eyes will be drawn to. Therefore, make sure these objects are relevant to the information that it is relating to. Another example of relative size is a pie with a missing piece. The missing piece will stand out and be perceived as an object.

• Figure and Ground - A figure is an object that appears to be in the foreground. The ground is the space or shape that lies behind the figure. When an object uses multiple gestalt principles, figure and ground occurs.

Now that we have an understanding that visual object perception is based on identifying patterns, we must be able to design visual displays that mimic the way our mind perceives information. Stephen Kossyln states “We cannot exploit multimedia technology to manage information overload unless we know how to use it properly. Visual displays must be articulate graphics to succeed. Like effective speeches, they must transmit clear, compelling, and memorable messages, but in the infinitely rich language of our visual sense” (Kossyln, 1990).

In his article, Kossyln identifies and describes five key principles for articulate graphics:

Display Elements are Organized Automatically

This follows gestalt principles. Objects that are close by, collinear, or look similar tend to be perceived as groups. So when designing information displays, like maps, adding indicators, landmarks, and objects that are clustered together, appear to be grouped and share a relationship. This may cause confusion when the viewer needs to locate his exact position.

Perceptual Organization is Influenced by Knowledge

When looking at objects in a pattern for the first time, the organization may not be fully understood or remembered. However, if this pattern is seen again over time, we tend to chunk this pattern and store it in our memory. Think of chessboard with its pieces played out. To a viewer who has never seen this game before, will perceive the board as having many objects. However, an experienced chess player, will immediately identify the objects and the relationships that have with each other and the board. So when designing visual displays, its essential to know the mental model of your user so they may quickly identify and relate to the information displayed.

Images are transformed Incrementally

When we see an object move and transform its shape in incremental steps, we have an easier time understanding that the two objects are related or identical. However, if we only see the object’s beginning state and end state, our minds are forced to use a lot of mental processing and load to understand the transformation. This can take much more time and also increase errors or confusion. So when designing carousel lists, make sure the viewer can see the incremental movement.

Different Visual Dimensions are Processed by Separate Channels

Object attributes such as color, size, shape, and position are processed with our minds using separate processing channels. The brain processes many individual visual dimensions in parallel at once, but can only deal with multiple dimensions in sequence. For example, when designing bullet list that are all black circles, we can immediate identify all of them. However, if you add a bullet that is black, same size, but diamond shape, our minds have to work harder to perceive them as being different.

Color is Not Perceived as a Continuum

Many times designers will use color scale to represent a range of temperature, like red is hot. Blue is cold. And temperatures in between will be represented by the visual spectrum. The problem is that our brains do not perceive color this way in a linear dimension. We view color based on the intensity and amount of light. So a better way of showing this temperature difference would be to use varying intensity and saturation.

Information Design & Ordering Data

The way people perceive attributes can be used directly to communicate the relative importance and relationship of informational elements on the page. This design of pages or states, when it falls directly from the information architecture of the entire product, can be called information design.

While many methods of considering these arrangements exist, an adequate grouping is, from most to least important. Position is, generally, more critical to communicating importance than size, which is more important than shape, and so on:

• Position - While relative position is unarguably critical, it can easily be lost. The annunciator row, with battery level and so forth, is not the most important, because it is almost lost in the bezel. This is purposeful, and the size is adjusted to account for it. Each attribute works with others to function properly.

• Size - Larger elements attract more attention, aside from providing more room for content. They can be too big, either obscuring other items, or exceeding the expectation size for an element. Buttons can be so large they are not recognized as buttons, for example.

• Shape - At the simplest, pointed shapes attract attention. Warnings should be triangles, helpful icons circles, for example. Rounded corners on some boxes, and square on others, will imply meaning. Make sure it's there, and not just a random design element.

• Contrast - Not color, but the comparative value (darkness) between two different elements, discounting color. More easily read, less affected by lighting conditions, and not as subject to users with color deficits.

• Color - High visibility colors attract more attention, with significant caveats. The most important is not always color blind users. Glare can make certain colors less prominent. Or pervasive use of the color in the branding; a site with much red cannot rely on it for warnings.

• Form - The last thing to use is specific forms of an element. The most common is type treatments, such as bold and italics.

These will be discussed in detail in other chapters as well. Here, the concept is useful when determining how to relate the elements within a single informational item, and how to keep the elements adjacent items from becoming mixed. Rules and bars of color are but some of the techniques. The list above covers six categories, with hundreds of design tactics included.

It is also useful to decide what information must be present. More can be said about a good, easy to understand interactive design by what is left out of any particular view, than what is included. For each of the information displays detailed below, only a portion is shown, and details, or alternative views are available when the user takes action.

Naturally, make these decisions by following heuristics, standards, styles of design that already exist such as OS-level standards, and universal hierarchies of visual communication. Most decisions for an existing platform can be made easier by consulting the style guide. Only a few choices will exist, and these will be well understood by the users.

Patterns for Displaying Information

A valid way of thinking about the entire topic of interactive design is that it is about displaying information. This chapter in particular is concerned with components whose sole task is presenting ordered sets of information, so that users may understand and act upon them.

These patterns have been developed and refined based on how the human mind processes patterns, objects, and information:

• Vertical List

• Infinite List

• Thumbnail List

• Fisheye List

• Grid

• Film Strip

• Slideshow

• Infinite Area

• Select List