## Univocality

The fact that your items are simple, doesn't yet guarantee that they are easy to remember. One of the powerful obstacles in creating easy knowledge systems is the problem of interference, or confusion, coming from the fact that two different items might have similar questions or similar answers. For example, imagine that you want to learn something about SuperMemo, and you create a special knowledge systems devoted to that purpose. Consider the two following items of your knowledge system concerning SuperMemo:

1. Q: What is the name of items which resemble one another?

A: ambiguous items

2. Q: How are similar-looking items called?

A: equivocal items

You need not much experience with SuperMemo to predict that the student who wants to master a knowledge system containing such two items will continually confuse ambiguous items with equivocal items until he discovers that he has two items whose questions are semantically identical but answers differ. The simple remedy to the problem is to formulate an item with two optional answers:
Q: What is the name of items which are similar to one another?

A: a. ambiguous items OR
b. equivocal items

In such a case, providing one of the answers is sufficient to classify the item as remembered (unless the user wishes to remember both terms and replaces OR with AND). The problem of interference is particularly visible in attempts to remember numbers. No simple trick of splitting items into subitems can suffice here. The ages long solution to the problem here is mnemonic techniques. One popular mnemonic technique is to represent numbers as pictures and attempt to remember scenes formed by those pictures instead of remembering numbers. For example, instead of having the item:
Q: What is the value of the constant p?
A: 3.14

the student might memorize the universal list of 10 pictures corresponding to 10 digits e.g.:

1 - harpoon (because 1 looks like a harpoon),

2 - coin (because a coin has two sides),

3 - tripod (because a tripod has three legs),

4 - dog (because a dog has four legs), etc.

and formulate the mnemonic item in the following way:

A: What is the value of the constant p?

Q: 3.14 because: p rhymes with fry and ... on a small tripod a big balloon is being fried (balloon represents the decimal point), suddenly somebody pierces the balloon with a harpoon, and from inside the bursting sphere a big dog jumps on the student.

Although construction of the pictured scene may seem awkward and time consuming, it ultimately yields items that in most cases are much easier to remember than those composed of dry numbers. The net result is saved time.