# Boolean Variable Rules Booleans can have only one of two possible values: `true` or `false`. They are commonly used in conditional statements to make decisions based on whether a certain condition is true or false. You can choose the Default Value as either `true` or `false`.

## Boolean: When Rules 1. **changes**: Gets triggered if the boolean variable undergoes a change. 2. **is TRUE:** Gets triggered if the boolean variable changes to `true`. 3. **is FALSE:** Gets triggered if the boolean variable changes to `false`.

## Boolean: Then Rules 1. **reset to default value** - This will set the variable back to its default value. 2. **set to true** - Sets the boolean to `true`. 3. **set to false** - Sets the boolean to `false`. 4. **capture data** - This action copies the value from the "When" side of the rule. Check [String Substitution](/metaverse/build/variables/string-substitution.md#capturing-user-input).

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