There is a popular belief that if you ask “why” five times you will get to the root cause of any problem. Here is a cool article about it.
The method was developed by engineers, and not by scientists, so we do not really know how well it works. It does show an interesting tendency of the brain to use 5 layers of information handling. Let us consider this as a guiding rule for a mindmap: any sufficiently complex mindmap should have 5 layers of data.
The method was initially developed by Toyota. While the questioning process can extend to a sixth, seventh, or even higher level, typically five iterations of asking “why” are enough to identify the root cause. The key is to encourage the problem-solver to avoid making assumptions and instead trace the chain of causality through layers of abstraction to the root cause. In engineering, the true root cause should highlight a process that is either malfunctioning or nonexistent. In learning, the root cause is likely an idea or a fact.
Consider a book as an example. What layers make up a typical book? Before delving into the specifics, it’s important to create a separate mind maps for the high-level information: title, authors, general subject, and major ideas learned from the book. With that foundation, let’s explore the details further.
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- Part.
A sufficiently big book consists of several independent parts. To some extent, each part is a standalone miniature book with its own ideas and methods. The parts are brought together to outline how different aspects of the subject coexist with each other.
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- Chapter
Each chapter outlines a specific subject from multiple angles.
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- Sections
A particular angle on the subject can be limited to several paragraphs, e.g. a section.
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- Paragraphs
The basic amount of knowledge the author assumes we can evaluate at once. If the paragraph is long, the author dilutes the information with supplying data. Short paragraphs introduce new ideas.
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- Ideas/Facts
Each paragraph contains a small number of ideas and facts which we may want to remember. When we ask ourselves “why” 5 times about a book, we will end up with a single idea or fact, usually a sentence within the book. Therefore 90% retention means we remember virtually EVERYTHING in the book.
Thus a 5-level (+root) mindmap of a book is probably sufficient to memorize an entire book in all of its complexity. Usually the resulting information tree will typically contain between 4 to 8 branches in each junction.
It is not uncommon to use chunking e.g. introduce 2 levels instead of one to reduce branching effect each time: for example we have on average 2 markers with 5 details each per paragraph to encode ~10 facts and ideas we encounter within. When we ask our students to outline the markers they get from the text, we originally get ~1 word per paragraph, and only after some discussion they understand they probably need to remember x10 more information to represent the data properly.
Now let us consider memorization of larger subjects. Unlike books the larger subjects are poorly organized, and an answer to a question would be a particular book or article.
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- Area of expertise.
Each sufficiently large subject can be divided into areas of expertise which are sufficiently wide for an expert in one to know very little about the other. For example, statistics as a distinct area of mathematics is a huge area of expertise.
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- Department.
Experts in one department are very different from each other, yet they can understand each other’s work. If you would build a college to describe your area of expertise, how would you build its departments?
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- School
Each subject can be approached from several schools or perspectives. Different schools analyze the same issues using very different sets of tools.
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- Approach
Approach is a tool within a toolset promoted by a school. It suggests a specific way to solve problems.
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- Publication
The basic publication describing the solutions.
Our understanding of subjects is not uniform. We may remember many publications for some approaches and only vaguely remember existence of other approaches. It is not uncommon to meet someone who can cite 100 publications for the approach he loves, so we definitely will need more complex mindmaps. Yet we can traverse huge layers of these mindmaps with a single WHY simply because all publications comply with the same approach or framework.
Life is not that simple, and a single item of information may appear on different layers of different information trees. We may use mnemonic tools to reduce duplication of knowledge and link different areas of expertise. The more elaborate mnemonic tools enable higher level of creative thinking and problem solving.
Most of our knowledge may be structured in 5-level mindmaps. Asking 5 WHY allows us to pass from the general subject to a particular fact or idea. The same concept enables us to build a powerful representation of our knowledge.
