Information Metaphors

The ways we deal with information since the advent of the web are new. Although people have dealt with information in the past — through spoken language, print media, in the environment, etc. — the web changed how we produce and use information. We don’t yet have precise language to describe the effects of this change upon us as individuals and societies.

Language reveals how we think about things. Given the newness of the experience, I’m curious about the metaphors we use to talk about how we use of information online. I’ve noticed three come up often:

  • information as resource,
  • information as sustenance, and
  • information as an environment.

Let’s look at them in more detail.

Information as Resource

Under this metaphor, we see information as something to be bought, sold, mined, traded, shared, etc. We can own information, gain access to it, stream it. We must protect our information lest it fall into the wrong hands.

Examples:

“A new commodity spawns a lucrative, fast-growing industry, prompting antitrust regulators to step in to restrain those who control its flow. A century ago, the resource in question was oil. Now similar concerns are being raised by the giants that deal in data, the oil of the digital era.” — The Economist

“Think twice about sharing your social security number with anyone, unless it’s your bank, a credit bureau, a company that wants to do a background check on you or some other entity that has to report to the IRS. If someone gets their hands on it and has information such your birth date and address they can steal your identity and take out credit cards and pile up other debt in your name.” — Christina DesMarais, TIME

Information as Sustenance

This metaphor posits that information is like food and drink; it changes us as we consume it. Information enters you and transforms you. You are what you eat; you are what you read online. As with food, you have the ability to say “no” to information, to change your consumption patterns. You could go on an “information diet” if you wished.

Examples:

“We monitor what we eat and drink, optimizing our diet for health and performance, not just enjoyment–and yet we can be heedless about what we read, watch, and listen to. Our information diet is often the result of accident or happenstance rather than thoughtful planning. Even when we do choose deliberately, the intent behind much of our media consumption is simply to soothe or distract ourselves, not to nourish or enrich. It’s like having french fries for every meal.” — Ed Batista

“We define digital nutrition as two distinct but complementary behaviors. The first is the healthful consumption of digital assets, or any positive, purposeful content designed to alleviate emotional distress or maximize human potential, health, and happiness. The second behavior is smarter decision-making, aided by greater transparency around the composition and behavioral consequences of specific types of digital content.” —
Michael Phillips Moskowitz

Information as Environment

Another metaphor is that of information as something you inhabit; an environment. Under this metaphor, information defines the boundaries of spaces where we interact. We’ve been using this type of language from very early in the online revolution; we’ve been talking of “chat rooms” and “home pages” for a long time.

Examples:

“When all discussion takes place under the eye of software, in a for-profit medium working to shape the participants’ behavior, it may not be possible to create the consensus and shared sense of reality that is a prerequisite for self-government. If that is true, then the move away from ambient privacy will be an irreversible change, because it will remove our ability to function as a democracy.” — Maciej Cegłowski

“Dark forests like newsletters and podcasts are growing areas of activity. As are other dark forests, like Slack channels, private Instagrams, invite-only message boards, text groups, Snapchat, WeChat, and on and on. This is where Facebook is pivoting with Groups (and trying to redefine what the word ‘privacy’ means in the process).

These are all spaces where depressurized conversation is possible because of their non-indexed, non-optimized, and non-gamified environments. The cultures of those spaces have more in common with the physical world than the internet.” — Yancey Strickler

While all three metaphors are valid, you won’t be surprised to learn I favor the “environment” metaphor — as evidenced by the title of my book.

The “resource” metaphor brings with it the language of ownership and trade. The “sustenance” metaphor reduces our agency to which types of information we choose to let in. (After all, most of us don’t produce our own food.) While both are valid, they miss an important angle: the fact that our interactions with each other and our social institutions are increasingly mediated through information. The language of inhabitation nudges us to consider the pervasive influence of information on our actions and empowers us to reconfigure our information structures to affect outcomes. It gives us agency with regards to information while acknowledging the degree to which it influences our decisions.

Have you found other information metaphors? Please let me know.

Good IA is Good Business

An emerging pattern: recognizing the findability of information as a central business concern. In some cases, it’s trumpeted as a competitive advantage. In others, its absence is recognized as a significant liability. For example, a couple of weeks ago, I wrote about how classical music streaming service IDAGIO is touting its search features as a competitive differentiator. And just last week, an article in The Verge highlighted the costs of poor metadata.

Following this trend, earlier this week, Apple’s WWDC keynote showcased structural changes to a few of its key apps. The company’s Podcasts app — one of the most popular in the world — is gaining a new feature that allows users to search for keywords in audio content. This represents a major improvement in findability, and the fact it got stage time during a very packed keynote is significant. (I’ve been told Google’ podcasts app has a similar feature.)

Another big change announced during Apple’s keynote was the structural redesign of iTunes on the Mac, which is being broken up into separate apps (as it is on Apple’s other operating systems.) In describing the rationale behind the changes, Apple exec Craig Federighi walked the audience through a history of iTunes, how it accreted features over the years, and how a different approach was now needed. It was a very compelling pitch for rethinking a complex system’s information architecture.

Although none of these examples talk explicitly about IA, they’re all showcasing the importance of digital systems’ structural layers to the businesses that operate them. As such systems become more complex and central to their organizations’ bottom lines, savvy business leaders will inevitably look to improve their information architectures. To paraphrase Thomas Watson, good IA is good business.

The Dollar Value of Metadata

As software eats more of the world, it becomes increasingly evident to people just how important it is to structure information correctly. It’s not just about finding and understanding stuff; in some cases lacking the right structure can be costly. One such case is that of music artists, which — according to an article on The Verge — are leaving billions of dollars on the table due to bad metadata:

Metadata sounds like one of the smallest, most boring things in music. But as it turns out, it’s one of the most important, complex, and broken, leaving many musicians unable to get paid for their work. “Every second that goes by and it’s not fixed, I’m dripping pennies,” said the musician, who asked to remain anonymous because of “the repercussions of even mentioning that this type of thing happens.”

Entering the correct information about a song sounds like it should be easy enough, but metadata problems have plagued the music industry for decades. Not only are there no standards for how music metadata is collected or displayed, there’s no need to verify the accuracy of a song’s metadata before it gets released, and there’s no one place where music metadata is stored. Instead, fractions of that data is kept in hundreds of different places across the world.

Although its description of what metadata is could be clearer (which I empathize with; this isn’t easy to describe to a general audience), the article does a pretty good job of highlighting some common issues that arise when organizations don’t deal with this stuff properly: a lack of standard frameworks, bad information, no clear mechanisms for collaboration, lack of agreement between the various parties involved, etc. It’s worth your attention:

Metadata is the Biggest Little Problem Plaguing the Music Industry

Establishing Context Through Navigation

The most important purpose of navigation structures in a website or an app is allowing users to move around. Links on​ a navigation menu make it possible for a person to go to different parts of the information environment​; they give the user clues on where they can go next. However, these structures also play another important — and often unacknowledged — role: they help establish the right context in the user’s mind. By this, I mean that they help answer the following questions:

  • Where am I?
  • What type of place is this?
  • What can I do here?

These questions are on people’s minds when they come to a new information environment — and navigation can help answer them. The distinctions we establish through the choices in a navigation menu tell us something about the place. Take a look at the following options from a navigation structure; let’s call it structure A:

  • Studio
  • Classes
  • Poses
  • Schedule
  • Search

You may not know what these options refer to, but a picture may be forming in your mind — a picture triggered by this unusual collection of words. Compare that with another structure, let’s call it structure B:

  • Products
  • Services
  • Support
  • About us
  • Search

Whereas structure A may pique your curiosity, I bet you don’t find structure B surprising: you’ve likely encountered it in many other information environments. “Products” and “Services” are generic terms; they could refer to anything. Structure B could work for healthcare or financial services or a myriad other fields. Structure A, on the other hand, is much more specific: that particular collection of words is likely to occur only in a few areas.

A new user encountering structure​ A must imagine him or herself in a particular context for these choices to make sense. This takes some cognitive effort. The labels in structure B, on the other hand, are familiar — clichéd, even. This can be useful: The user doesn’t need to know how the place is different in order to predict what s/he’ll find in each area of the environment.

On the flip side, the more generic labels in structure B sacrifice something important: the opportunity to quickly put the person in the right mindset to make skillful use of the place. Structure B trades off specificity for familiarity; “services” hints at a much broader range of possibilities than “classes.” This tradeoff influences people’s ability to understand the place. It also affects the positioning of the environment in search engines, since there are many more information environments offering “services” than “poses.”

One of the potential downsides of using domain-specific labels is that the more specific labels can be obscure, so you risk alienating visitors who don’t yet understand the subject matter domain. I see this most often with navigation structures that use proprietary labels (e.g., brand names.) If the proprietary name is relatively new, users may not know what it refers to. So these structures work best when the proprietary names are well known. For example, consider the following options:

  • Office
  • Windows
  • Surface
  • Xbox
  • Deals
  • Support

You may have already guessed that this is from Microsoft.com’s primary navigation bar. Here the (otherwise) generic words “office,” “windows,” and “surface” refer not to the everyday concepts bearing those names, but to well-known brands. This set of labels depends almost entirely on their context — which they reinforce. If this site wasn’t related to Microsoft somehow, we’d be wondering why we’re seeing this particular collection of concepts.

The set of labels we present in navigation structures help people move around. But they also frame the experience. They put the user of the environment in a particular mindset. For example, imagine you stumble unto a website that offers the following options:

  • Banking and Cards
  • Loans and Credit
  • Investment and Retirement
  • Wealth Management
  • Rewards and Benefits

I don’t need to show you anything else — not even the website’s name — for you to know that you’re now in some kind of financial services environment. Just looking at the words would lead you to conclude this is most likely a bank. And if you’ve had experience with online banks in the past — a safe bet for many users — you’ll have expectations about what you can find and do in each of the areas of the environment. For example, you’d expect such a place to have a way for you to log in to see your own accounts and to transact with the organization, since that’s a feature offered by most bank’s websites. If your structure doesn’t allow users to do this, they’ll be wondering why.

When establishing a new navigation structure — especially its top-level options — you should strive to have the set of choices create and reinforce the right context. Ask yourself: Are the options understandable? Are they particular to this information environment? Do they help the environment stand out? Or are they generic? Are we establishing the right degree of familiarity for this environment? Are we sacrificing understandability for expedience? Getting the balance right requires a clear understanding of the people will be using their environment — especially the degree to which they already understand the subject matter and the organization’s role — and lots of testing.

Informing and Persuading

As more things become digital, those of us who design digital things — apps, websites, software — increasingly define how people understand and interact with the world. It’s not uncommon for digital designers to make difficult choices on behalf of others. This requires an ethical commitment to doing the right thing.

For information architects, the critical decisions involve structuring information in particular ways. Choices include:

  • What information should be present
  • How information should be presented (i.e., in what format or sequence)
  • How information should be categorized

The objective is to make information easier to find and understand.

At least in theory. Often, the objective is to make some information easier to find than others. For example, it recently came to light that tax filing software makers such as Intuit and H&R Block set out to steer customers away from their free offerings. Intuit even tweaked its site, apparently to keep public search engines from indexing the product. The goal in this case seems to be not to make information more findable, but less so — while still technically complying with a commitment to “inform.”

The same is true for understandability. A few years ago, when the Affordable Care Act was being debated in the U.S., a diagram was put forth that purported to explain the implications of the new law:

Understanding Obamacare chart

This is not a neutral artifact. Its primary design objective isn’t to make the ACA more understandable, but to highlight its complexity. (It succeeds.) This diagram intentionally confuses the viewer. As such, it’s ethically compromised.

IA challenges fall on a continuum. On one end of the spectrum, you’re aiming to inform the people who interact with your artifact about a particular domain. On the other end, you’re trying to persuade them.

Inform - Persuade

By “inform,” I mean giving people the information they need so they can make reasonable decisions within a conceptual domain, and presenting this information to them in ways they can understand given their level of expertise. By “persuade,” I mean giving people the information they need so they can behave how we want them to, and presenting it to them in ways that nudge them in that direction.

Informing and persuading are different objectives. In one, you’re setting out to increase the person’s knowledge so they can make their own decisions. In the other, you’re setting out move them towards specific, predetermined outcomes. In both cases, you’re trying to alter behavior — but the motives are different. By informing, you make people smarter. By persuading, you make them acquiescent.

I’m not judging by observing this distinction. If someone is engaged in self-defeating or otherwise destructive courses of action (e.g., smoking, gambling, driving while intoxicated), setting out to change their behavior could be the compassionate, ethical thing to do. So persuasion isn’t bad per se. Also, few projects fall on either extreme in the continuum; most lie somewhere in the middle. (Is it ever possible to not persuade when structuring information? I.e., all taxonomies are political. Even this post is an exercise in persuasion.)

That said, if your goal is to make information more findable and understandable, you will sometimes be tested by the need to persuade. If the offering truly adds value to clients and to the world, and aligns with your own values, you’re unlikely to face a tough ethical call. Such offerings “sell themselves” — i.e., the more you know about them and their competitors, the more desirable they become. The problem comes when you’re asked to sell a lemon or to nudge people towards goals that are misaligned with their goals, your goals, or society’s goals. There’s no ethical way to bring balance to such situations; often the appropriate response is to take a “hard pass.” (I.e., not engage in the work at all.)

Thoughts on the First IA Conference

I just returned from Orlando, where I had the opportunity to attend the first ever Information Architecture Conference. That’s somewhat disingenuous: “IA Conference” is only a new name for the conference formerly known as the IA Summit. The name was changed this year due to a transition in stewardship: the event is no longer organized by ASIS&T but by the Information Architecture Institute. In any case, I’ve been attending this gathering since 2005, missing only one year since. So even though technically this was my first “IA Conference,” it was actually my fourteenth event.

Given the change in name and management, I expected this year’s conference to have fewer attendants than in previous years. That proved to be the case. I don’t have the numbers, but this felt like the smallest version of this conference I’ve attended. Perhaps my perception was influenced by the setting, the cavernous Renaissance Orlando at Seaworld. This hotel features a very large atrium that served as the setting for many of the conference’s meals and informal gatherings. It’s a place designed to accommodate large groups, and it made our small gathering feel smaller. (Where a smaller venue would’ve made the gathering feel more intimate.)

The weather was relatively warm, which allowed us to enjoy a few outdoor activities. The conference’s opening reception was held in one of the hotel’s “lawns” (actually covered in AstroTurf.) This lawn was also the setting for the first of two Polar Bear Yoga sessions that I hosted (and that were graciously sponsored by Rosenfeld Media.) This was my third year hosting yoga sessions at the conference, but the first in a setting that allowed us to practice outdoors. It made a big difference: we had the opportunity to do sun salutations as the sun was rising, and got to lie in Shavasana to a soundtrack of birdsong and (artificial) waterfalls. (Alas, the following day’s Polar Bear Yoga session had to be moved to a conference room due to changes in the weather; it got cooler and wetter.)

Besides hosting Polar Bear Yoga, I also led my Information Architecture Essentials workshop at the conference. This workshop is designed to serve as an introduction to the discipline of IA through a high-level overview of the material in the polar bear book. As a result, the workshop attracts folks who are new to the discipline (and to the IA Conference community as a whole.) It’s always a pleasure for me to meet enthusiastic newcomers to our discipline. I still remember the thrill I felt when I discovered early on in my career that there was a community of practice that did what I did. Interacting with folks who are discovering the discipline energizes me and fills me with a sense of responsibility towards our community.

This year I felt that sense of responsibility more strongly than in past years. As I’ve already mentioned, this was a smaller conference than previous ones. Again, I don’t have the numbers, but my perception was that there were relatively less first-time attendees than in previous years. (Again, predictable given the name change; people already “in the know” were more likely to come than people who were looking for something called “IA Summit.”) So I’ve been mulling questions about the conference’s future. What do these changes entail for my “home” community of practice? With newcomers outnumbered by old-timers, do we run the risk of coming across as insular? How do we engage more newcomers? There are people in the world doing this sort of work and not knowing what it’s called. How will they find our community and its yearly gathering? More to the point, does this smaller gathering signal the beginning of a downward spiral in attendance/interest or will it usher a time of reinvention and renewal?

I wasn’t planning to address these issues publicly. However, a last minute speaker cancellation led to my being invited to an impromptu panel about the past, present, and future of the IA Conference (alongside IA luminaries Jesse James Garrett, Lou Rosenfeld, Stacy Surla, and Noreen Whysel, and moderated by one of the conference chairs, Amy Marquez.) The discussion in this panel prompted more thoughts about what this gathering is about and how we can get more people to know about it.

This is where I landed: I went to my first IA Summit because I wanted to meet the people behind the blog posts, books, and online forums I was already immersed in. In so doing, I discovered my community of practice. More than any other conference I’ve participated in, the IA Conference is a gathering of a tribe. (The metaphor of a family also came up during the panel, but I think “tribe” is more apt.) The Conference thus serves two purposes: it’s a way to advance the discipline of information architecture and a yearly gathering of this community.

The IA Conference community gives a lot of thought to increasing the diversity of people who join this tribe. This manifests in various activities and facilities designed to make newcomers feel welcome and safe, such as first-timers dinners, mentoring tracks, a robust code of conduct, bingo cards to spark conversations, etc. That said, while we try to make newcomers feel at home, we don’t make it easy for people who don’t already self-identify with the discipline to discover the community or the quality conversations we have every year at this event. Once they come, they feel like they belong — as evidenced by this tweet from one of the first-time participants in my workshop:

I remember that feeling: “Wow, these folks are working on the same things I am! And they’re into the same sort of stuff I’m into! Is this my professional tribe? OMG this is my professional tribe!” There’s huge value to this discovery, but somehow you must be drawn to the conversation before you realize its value. The key question is: How do we reach out to the people who will find value in participating in this community but don’t know to look for it?

As I said during the panel, I’ve made lifelong friendships at the IA Summit, and now the IA Conference. Joining this community of practice has had an enormous influence on my career. I know it can do the same for others. This year was a moment of transition for this community, if not for the discipline it represents. I left Orlando wondering: What are we transitioning towards? How can this discipline and the community that has formed around it become more sustainable in the long term? How can we open up more so that more folks can discover and participate in both?

A Space for Collaboration

Yesterday I spent most of the afternoon working with a friend and colleague. We were synthesizing the results of a workshop we co-facilitated earlier in the week. It was fun, but I often felt constrained by the limitations of the space we were in and the technology we had available.

This type of work usually requires reviewing lots of photos from sketches and stickies posted on walls. My friend and I bounced ideas and memories from the workshop off of each other; we spotted patterns in these materials and captured them in a presentation deck. It’s easier to do this sort of work if we can both see the photos and files we’re editing. We took over the living room in my house, where we had access to ample wall space and projector. We projected photos from the workshop on one of the walls in the space, while we sat on the couch discussing their implications.

While this sounds like the ideal setup, soon it became apparent that there were limitations. For example, we were constrained to a single rectangular window of information on the wall. We could show photos and the document we were editing, but only if we split this rectangle, reducing our ability to see what we were doing. This was workable but not ideal.

A bigger issue was that only one of us could control what was being projected. For example, I was examining the photos from my laptop and my friend was editing the presentation deck. If I was sharing the pictures on the wall, we couldn’t see changes to the presentation deck and vice-versa. Yes, there are workarounds to this problem. For example, we could’ve used Google Docs (or something equivalent), which would’ve allowed us to edit the deck jointly. But this wasn’t ideal either. We spent more time than I would’ve liked trying to figure out how to best collaborate in this setup.

What I wanted was for all of the walls in my living room to be “digitally active” — to allow us to arbitrarily distribute our work around the room and jointly control it. Current computer display technologies are based on a one user/one computer/one display paradigm; projectors are treated as a display that is expected to be displaying the information of one computer at a time.

Instead, I’d like to place various photos on the walls around the room — perhaps recreating the space of the workshop. My friend would put his presentation on another wall. Both of us could then annotate and edit these digital objects arbitrarily. We’d be inhabiting a physical space that was also digitally active, a shared computing environment that we could inhabit and manipulate together.

Something like this is already being built at Dynamicland. That project features a space that allows users to manipulate digital information with physical artifacts. The digital information is projected onto the environment, with cameras detecting the positions of objects in physical space. As you manipulate these objects, the information projected on them changes. It’s a fascinating environment, one pregnant with potential. However, Dynamicland’s objective isn’t to extend our current collaboration paradigms but to reinvent them.

What I’m describing here is conceptually different: I want the sort of stuff we’re used to moving around in computer windows in our laptops and desktop computers up on the walls, while transcending the current single-user paradigm. (It’s a much more conservative vision than Dynamicland’s.) Does such a thing exist? (Perhaps using augmented reality instead of projectors?) It seems like it should be feasible.

Two Approaches to Structure

There are at least two approaches to structuring a digital information environment: top-down or bottom-up.

In the top-down approach, a designer (or more likely, a team of designers) researches the context they’re addressing, the content that will be part of the environment, and the people who will be accessing it. Once they understand the domain, they sketch out possible organization schemes, usually in the form of conceptual models. Eventually, this results in sets of categories — distinctions — that manifest in the environment’s global navigation elements.

Top-down is by far the most common approach to structuring information environments. The team “designs the navigation,” which they often express in artifacts such as wireframes and sitemaps. This approach has stood the test of time; it’s what most people think of when they think about information architecture. However, it’s not the only way to go about the challenge of structuring an information environment.

The other possibility is to design the structure from the bottom-up. In this approach, the team also conducts extensive research to understand the domain. However, the designers’ aim here is not to create global navigation elements. Instead, they’re looking to define the rules that will allow users of the environment to create relationships between elements on their own. This approach allows the place’s structures to emerge organically over time.

Consider Wikipedia. Much of the usefulness and power of that environment come from the fact that its users define the place. Articles and the links between them aren’t predefined beforehand; what is predefined are the rules that will allow people to define elements and connections between them. Who will have access to change things? What exactly can they change? How will the environment address rogue actors? Etc.

Bottom-up approaches are called for when dealing with environments that must grow and evolve organically, or when the domain isn’t fully known upfront. (Think Wikipedia.) Top-down approaches are called for when dealing with established fields, where both content and users’ expectations are thoroughly known. (Think your bank’s website.) Most bottom-up systems will also include some top-down structures in their midst. (Even Wikipedia has traditional navigation structures that were defined by its design team.)

So do you choose top-down or bottom-up? It depends on what problem you’re trying to solve. That said, I find bottom-up structures more interesting than top-down structures. For one thing, they accommodate change more elegantly — after all, they’re designed to change. This approach requires that the team think more carefully about governance issues upfront. Bottom-up structures are more challenging to design and implement. Designers need to take several leaps of faith. They and the organization they represent are ceding control over an essential part of the environment.

Most information environments today are designed to use top-down structures. Some have a mix of the two: predefined primary nav systems and secondary systems that are more bottom-up. (Think tagging schemes.) I expect more systems to employ more bottom-up approaches over time. Tapping the distributed knowledge of the users of a system is a powerful approach that can generate structures that better serve their evolving needs.

Designing the Frame

Information architecture is a systemic design discipline. The bulk of the work consists of establishing distinctions. These distinctions are in service to creating particular contexts that allow individuals to “find their own paths to knowledge.” As a result, the nature of the IA challenge is holistic; we’re fixing a whole so the brain gets in.

A system, you’ll recall, is a set of elements that interact with each other in particular ways that allow the whole to achieve a purpose. This calls for a “big picture” perspective: understanding the system’s purpose and how the interactions between its parts lead towards desired outcomes.

Consider an e-commerce website. A high conversion rate could be one desired outcome for such a system. Perhaps its current semantic structures aren’t doing a good enough job of supporting customers as they go through the purchasing process. The information architect will carefully consider labels and groupings that improve the customer experience. These labels and groupings establish distinctions in the customer’s mind. But the point is not the labels or groupings (or even the distinctions they create) per se; it’s how they work together as a whole to create a good experience.

Systems are important to information architecture on two levels. On one level, the thing we’re working on — what we’re enabling with our sets of distinctions — is a system. Like any other enterprise, an e-commerce website is a system. The business has inputs, outputs, and processes that transform the former into the latter. Information architecture defines the context in which these transformations happen, in much the same way that (building) architecture creates the context in which a “brick and mortar” store operates. Architects are frame-makers; they define the environments systems operate within.

On another level, the design of this frame is also a systemic undertaking; the information architecture itself is also the result of a system. The design of the context doesn’t stop when the website is put in production. Instead, the context is continuously re-created as conditions change. Perhaps customers are buying more of one type of product than another or the relationship with a supplier has ended or a new competitive threat has emerged. Whatever the case, the business is not a static entity. If the business is to serve its purposes — achieve desired outcomes — its architecture must evolve along with it.

This is an ongoing, dynamic, emergent process that requires design at a higher level of abstraction. Information architects are called to define the structure of the place, but they’re also called to define the (ongoing) processes that generate the structure of the place. Increasingly, we design not just the frame around the work, but also the systems that allow that frame to continue serving its purposes as conditions change.