Two heads are better than one: What second brains say about how developers work

Do we work better when we outsource our memory to other tools?

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“You’ve visited this page many times.”

Stack Overflow’s annual Developer Survey answers plenty of questions, but it always raises some new ones, too. Like: Why do our brains work the way they do?

Two years ago, we asked how you feel when you search for an answer and find a purple link—that is, a previously-clicked one. Fifty-two percent of you described your reaction as “Hello, old friend”: meaning you’ve searched for and located this information before. Maybe you’re trying to remember how to exit Vim (again), or maybe you just need to grab a specific regex. Either way, that purple link is reassuring—and, perhaps, exactly what you were looking for.

With more than half of developers greeting purple links like old friends (and another 16% reacting with amusement), it was apparent that people were visiting the same questions repeatedly. In fact, we found that 62% of Stack Overflow’s regular users visited the same question more than once in a three-month span.

Clearly, many of us are eager to outsource the work of information recall by treating external information repositories (especially those rich in user-generated content, such as Stack Overflow and Reddit) as second brains: personal knowledge management systems supported by technology.

This got us thinking: Is this an effective use of brainpower? Does the space we free up by deploying a second brain get used productively for something else? Or is relying on a second brain a lazy habit that leaves us less knowledgeable, capable of making fewer connections?

When I was doing my doctoral work in English and new media studies, I had a tendency to use Wikipedia to keep track of high-level definitions and straightforward details, like when a book was published or when a historical event happened. The definition of “epistemology” stubbornly refused to stick in my head, as did the year Ray Bradbury first published “A Sound of Thunder,” so I found myself searching for this information once a week or so, clicking that friendly purple link every time.

Another example: I’ve been making the same oatmeal cookie recipe for years, but I have yet to memorize it; I just Google it whenever I have a craving. Effectively, I rely on the search bar and the purple link to remember the recipe for me.

Why is it easier or more expedient to call up the same information over and over again, rather than committing it to memory? What does our dependence on second brains tell us about the way we learn and work? And for developers, who are constantly deluged with new and complex information, how can the right second brain help your original brain work better?

What is a second brain?

A second brain is a personal knowledge management system, especially one enabled by technology. The term is often credited to thought leader and author Tiago Forte, whose Building a Second Brain course has done a lot to popularize the concept. (These illustrated notes do a great job of summarizing the course material.) More specifically…

A second brain is a way of capturing and organizing information to realize its value

A second brain helps you get a handle on the volume and complexity of information you’re exposed to at virtually all times, with the eventual goal of translating that knowledge into something useful. This is especially critical for developers and other people whose work involves constant exposure to an ever-expanding pool of complex, technical information. Without help from the structures and technologies that comprise a second brain, you can’t absorb or remember the information you’re immersed in, much less call up that information when you might need it to solve a future problem or kick off a new project.

One simply siphons the excess thoughts from one’s mind, pours them into the basin, and examines them at one’s leisure. Albus Dumbledore
HarshLight from San Jose, CA, USA, CC BY 2.0 https://creativecommons.org/licenses/by/2.0, via Wikimedia Commons

In the Harry Potter series, Dumbledore’s Pensieve serves a second-brain function, storing disconnected thoughts and memories and shaping them into coherent patterns to inform actions and decisions. “One simply siphons the excess thoughts from one’s mind, pours them into the basin, and examines them at one’s leisure,” explains Dumbledore. “It becomes easier to spot patterns and links, you understand, when they are in this form.”

A second brain reduces cognitive load by doing your thinking and remembering for you

Think of a second brain as an extension of your mind: somewhere you can offload cognitive work so you don’t have to struggle to remember information or put it to good use. Like Sherlock Holmes’s mind palace, a second brain is a system for collecting, storing, and curating the tide of information that continually washes over us. “It’s a way of ensuring that the ludicrous amount of information we have to deal with day-to-day stops bouncing around our heads and is recorded somewhere where we can make sense of it in the long term,” explains Stack Overflow developer advocate and evangelist Matt Kiernander.

A second brain is built on digital technology

It’s certainly possible to cobble together a second brain using manual methods, from a notebook to a filing cabinet to a wall plastered with sticky notes. In college, I took notes in the margins of secondhand books as I read, blithely assuming I would remember what my scribbled abbreviations meant (spoiler: I would not, nor would the bookstore buy back any of my books).

None of these analog methods is scalable, portable, searchable, or capable of handling data in any format—all essential qualities in the kind of second brain you need. Unless you have access to a Pensieve, I suppose, a digital second brain is far and away the best and most natural choice for most of us who sit in front of computers all day. Your second brain must be:

  • Scalable, so you can capture and preserve a virtually unlimited amount of information.
  • Capable of storing and organizing data in various formats, from images to videos to chunks of code.
  • Portable, to permit quick capture and editing of information.
  • Searchable, so you can easily pull up the knowledge you need when you need it.

What platforms are developers using as their second brains?

We’re awfully proud of the fact that 90% of developers turn to Stack Overflow when they get stuck, often via a navigational query. (For example, “how to exit vim stack overflow” will take you to this question, viewed 2.7 million times and counting.) Often, developers return to the same question or answer regularly. More than 60% of regular Stack Overflow users visit the same question more than once in a three-month period—so if you’re thinking, “Didn’t I just look this up?”, the answer is probably yes.

These findings reveal how many developers rely on our public platform to serve a second-brain function. Most developers are inundated with information: languages, libraries, frameworks, and tools with their own use cases, shortcuts, workarounds, and optimizations. Second brains tailored for developers’ needs help us capture, organize, and surface knowledge, reducing cognitive load while realizing more value from the knowledge we’re exposed to.

Other second-brain tools developers favor include Notion (whose digital system is actually called Second Brain), Obsidian (which bills itself as a personal second brain), Evernote, and Roam, just to name a few.

What does our reliance on second brains reveal about how we think and work?

Knowing that so many of us rely on second brains, we wondered what this dependence could tell us about human memory and cognition, especially when it comes to developers and how they work.

We need help accessing knowledge and memories over time

In his 2001 book The Seven Sins of Memory: How the Mind Forgets and Remembers, Harvard researcher Daniel Schacter defines seven “sins of memory,” including transience and absentmindedness, the two failings most relevant to us here.

Transience refers to memories that simply don’t stick in our minds, or “the decreasing accessibility of memory over time,” according to the American Psychological Association. This usually involves new information that you’re trying to remember, from an unfamiliar function to the name of that person you were just introduced to.

Absentmindedness refers to “lapses of attention and forgetting to do things,” per the APA. “This sin operates both when a memory is formed (the encoding stage) and when a memory is accessed (the retrieval stage).” Classic examples of absentmindedness: forgetting where you left your phone, accidentally throwing away half a billion in Bitcoin, or leaving your $3.5 million cello in the back of a cab.

A second brain helps us overcome transience and absentmindedness by allowing us to categorize, search, and retrieve information and experiences. Ideally, a second brain empowers you to work “more effectively in the moment,” writes Tiago Forte: “You can spin up and complete your projects far faster because you’re starting with a collection of valuable material and reusing work you’ve already performed instead of a blank page.”

We’re overloaded with information…

As we’ve previously covered, there’s a strong correlation between how much attention we give something and our ability to remember it later. Both transience and absentmindedness are exacerbated when we’re unable to focus, and chronic multitasking can cause us to perform worse on simple memory and cognition tests, according to a study from the Stanford Memory Laboratory. Things get even harder for people experiencing significant stress and anxiety at work, whether those feelings stem from clinical anxiety or a professional culture of looming deadlines, unsupportive managers, and unrealistic expectations.

Most developers encounter constant, overlapping distractions: pings from chat and email programs, urgent tickets, the need to write code while joining calls and preparing for other meetings. In such a noisy environment, it’s no wonder that things slip your mind. Information overload leads to information exhaustion: We’re exposed to so much information every day that we simply can’t absorb and remember it all without an assist from technology. If you’ll pardon the plug, this is why companies like Microsoft, Dropbox, and Elastic use Stack Overflow for Teams as an organization-wide second brain, to ease the cognitive burden of constant context-switching and to manage collective knowledge.

…but we don’t want to miss anything

While most of us are all-too-aware of our information exhaustion, it’s still a priority for us to absorb and retain as much information as possible, especially as we move from project to project or job to job. But that’s much easier said than done. Developers face a proliferation of programming languages, frameworks, libraries, and tools, all of which have various, sometimes-overlapping applications, best practices, common pitfalls, and so on. No wonder some feel there’s simply too much to learn.

A second brain allows us to reduce noise and manage information overload without worrying that scraps of invaluable knowledge will slip through the cracks while we have 800 different mental tabs open. “By outsourcing the job of remembering to an external tool,” writes Forte, “we gain the peace of mind of knowing exactly what to do with each piece of incoming information and the confidence that it will never be forgotten.”

Matt Kiernander points out that a second brain is enormously helpful for retaining the knowledge you’ll need for repeatable tasks. If, like Matt, you find yourself Googling how to set up PATH variables for your command line every time you set up a new environment, or trying to remember the predefined list of tools and npm packages you need to install, offloading that information to a second brain could save you hours of time and didn’t-I-used-to-know-this frustration.

Second brains also allow you to make the knowledge you acquire as you move between jobs and projects portable, so that you can bring information like useful code snippets with you on your professional journey. The same goes for using your second brain to document the educational resources you encounter as you learn different technologies, languages, and systems.

The best developers are constantly learning: reskilling and upskilling, mastering new systems, adding additional languages and technologies to their repertoires. Instead of information going in one ear and out the other, a second brain “helps you take control of your own learning,” says Forte, curating your learnings in a searchable format you can return to anytime you need to.

Innovation is rooted in knowledge

When you can access information from your personal knowledge store when you need it, you can apply that wealth of experience to new skills and new projects. The idea is to surround yourself with context-rich associations and priceless nuggets of insight and problem-solving that you’ve collected and stored over time—the contents of your mind palace. The value of a second brain goes way beyond reminding you (once again) how to exit Vim or how much brown sugar your favorite cookies call for. It’s about making your learnings, insights, and experiences accessible and actionable as you navigate your professional journey.

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