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Building the knowledge tree

The knowledge tree is the hierarchical structure of elements as displayed in the contents window (as in the picture below). Before you get lost in details of the knowledge tree, remember that: knowledge tree is NOT essential for your success in learning! 

The structure of the knowledge tree does not affect the learning process! Many beginners believe that a good structure of the tree will help them prioritize their learning; however, you should NOT begin your adventure with SuperMemo from studying the tree, unless you have mastered the ABC!

Being exposed to a mixture of material belonging to different subjects will only make learning more fun (variety is the spice of life). Despite a widespread myth, mixed up learning can improve your retention (exceptions are discussed elsewhere at supermemo.com). Mixed up review of different subjects is the norm, not an exception in SuperMemo!

However, once you master the basics of SuperMemo, you can occasionally benefit from the knowledge tree by keeping various learning subjects separate. At times, it may help you handle a single subject as a whole (e.g. review a single subject before an exam, postpone a subject of lower priority, etc.).

Why isn't knowledge tree a priority?

Knowledge tree helps you keep order in your collection and process portions of material relating to different subjects. However, it does not reflect the structure of knowledge that you keep in your mind. The structure of knowledge that you remember is built gradually via semantic links between elements. You do not have to build those links in SuperMemo in any other way than by composing new items and topics and understanding the meaning of inter-related concepts that you learn. In simple terms, you build the map of knowledge in your mind, not in SuperMemo! SuperMemo carries only tiny granules of knowledge and connections between pieces of knowledge. Those granules and connections help you effectively refresh the structure of knowledge that you want to store in your mind.

Building the tree 

Important! To understand this text you need to understand the tree terminology. It is quite intuitive as it refers to roots, branches and leaves. However, if you have any problems, see: Tree Glossary.

There are two basic methods of building the knowledge tree:

  1. Using the contents window. You can use operations such as Add, Insert or Delete to build the tree directly in the contents window
  2. Using categories. If you want to add a large number of similarly looking items to a single branch, you will rather want to use categories. Categories automatically use templates to make sure that your elements are filled out with components of a desired look, number, size, etc.

When you choose Add new, new items are added to a single location determined by the current category (i.e. not by the current selection in the contents window). Advanced users will always prefer using categories to save learning time. Usually you add all your material to a To Do branch. Then you move only the most important portions of knowledge to separate categories.

Once you create a tree, you can always modify it using drag&drop operations.

Building the tree in the contents window

In the element window, if you see an element whose location in the knowledge tree is not satisfactory, you can quickly move it to a new location with Edit : Move on the element menu (Ctrl+Shift+V). Simply find the desired location in the knowledge tree and click Accept in the contents window (or press Enter).

If you build a small collection with a complex tree structure, you may prefer to use the contents window operations to build the tree:

  1. If you choose Add, a new child will be added to the currently selected element (click Add several times to see how this option works)
  2. If you choose Insert, you will add a new sibling. The new sibling will be inserted in the place of the currently selected element. The selected element will move one position down (press Ins a few times to see how this option works). You cannot insert a new element in the place of the tree root
  3. If you choose Delete, you will delete the currently selected branch (i.e. the selected element and all its descendants). You cannot delete the tree root

Once you add an element or a few elements, you can modify their titles. To do so, select the element by clicking and click it gently again. You can also choose View and press Alt+T to conveniently edit the title in the element window. If you fill out elements with texts (e.g. by typing questions and answers), SuperMemo will automatically generate titles for you.

When building the tree with Add and Insert, the type of elements added is determined by Topics/Items setting on the toolbar (top of the contents window). If you select Items, you will add simple question-and-answer items. If you chose Topics, you will add article-type elements that can be filled with text.

The contents menu includes more operations for modifying the tree (e.g. New : Folder, New : Item, etc.).

Once you create a tree, you can always modify it using drag&drop operations.

Building the tree using categories

Categories are portions of the knowledge tree that use the same look of elements. These elements usually belong to a single subject. For example, you can define a category called Biology and keep there all items related to biology.
If you select a given category on the Tools toolbar, each time you click Add new (or press Alt+A), you will add a new item to that category. For more details see: Using categories.

Modifying the tree using drag&drop operations

If you would like to modify the structure of the tree, you can do it easily with drag&drop operations in the contents window.

Modifying a tree is as simple as dragging a branch from one location to another (in the contents window or between two contents windows). To drag a branch, click it with the mouse, hold down the left mouse button, move the mouse to another branch (still holding the mouse button) and release the left button once you are over the target branch. The dragged branch will be moved to the target branch. You can also select more than one branch for dragging to a new location.

There are two dragging modes that will affect the way in which the moved branch is attached in the new location. You select the modes using the selection box on the edit toolbar at the top of the contents window (the box with Replace target in the picture). The dragging modes are:

  1. Replace target. In this mode, if you drag a branch onto another branch, the dragged branch will replace the target branch and the target branch will move one position down
  2. Add as last child. In this mode, the dragged branch will be moved to become the last child of the target branch. In this mode, you cannot drag a branch onto any of its descendants because a branch cannot become its own child or descendant

If you change the dragging mode, the change will affect all dragging operations in the future, even if you quit SuperMemo.

Important tips:

  1. If you drag between remote branches, you can open a second contents window and drag between the two windows. It is easier to open the source branch in one window, and then open the target branch in the other. To open a second contents window, click the blue Contents alignment icon on the contents window toolbar
  2. You can select many branches for dragging by holding the Ctrl key down while clicking the branches that are to be moved
  3. You can always move a single element currently displayed in the element window with Ctrl+Shift+V (press Enter after selecting the new location in the knowledge tree)

Status icons: pending, memorized and dismissed 

All branches in the tree are marked with small icons that indicate the status and type of a given element in the learning process:

Note that:

The plus sign to the left of the element indicates that the element has children. You can see the children when you click the plus sign. The minus sign to the left of the element indicates that the element with children can be collapsed. When you click the minus sign, all children will disappear from view and the minus sign will be replaced with a plus sign

Tree Glossary: what are roots, branches, children, and siblings

The tree presented in the picture begins with the root named All my knowledge at the top. 

There are seven visible branches growing from the root: Sciences, English, Private, New Imports, Tasklists, Archive and TO DO. There are more branches under TO DO that are not visible in the picture. All branches growing from a given branch are called children. The branch Sciences has five children displayed in the picture: 

  1. Business, Law and Economics
  2. Political and Social Sciences
  3. Science and Technology
  4. Medical Sciences
  5. Computer Science

All the branches listed above are their own siblings. For example, Medical Sciences are a sibling of Computer Science. On the other hand, Sciences is the parent of all its children (e.g. Business, Economics and Law).

At the very bottom of the structure there are leaves, i.e. children that do not have further children.

Please note that the root, branches, children, leaves, etc. are all elements in SuperMemo. This means that you can view them in the element window and fill them out with components (such as texts, pictures, sounds, etc.). To view a given element in the element window, select it and choose View at the bottom of the contents window

See also: FAQ: Knowledge tree