Types of Capacity
Testamentary Capacity verses Contractual Capacity
Two primary types of capacity include Testamentary Capacity and Contractual Capacity. Each differs in a unique way.
Testamentary Capacity
Testamentary capacity refers to the ability of a person to make a valid will. Most states have both an age requirement (usually 18 years old) and a mental capacity requirement.
To have mental capacity, the testator must have the ability to know:
- the nature/extent of property
- the natural objects of her property
- the disposition that her will is making
- the ability to connect all of these elements together to form a coherent plan

Contractual Capacity
When an individual is mentally disabled or otherwise lacks mental capacity, a contract will be treated as voidable because of the lack of contractual capacity. There are two tests utilized by states to determine if one lacks mental capacity: the cognitive test and the affective test.
- Cognitive Test: Under the cognitive test, a contract will be treated as void if the mentally disabled person fails to understand the meaning of the words in the contract. If so, the contract must be invalid.
- Affective Test: Alternatively, under the affective test, if one of the parties cannot act in a reasonable fa