The motivational intensity theory states that the difficulty of a task combined with the importance of success determine the energy invested by an individual. The theory has three main layers. The innermost layer says human behavior is guided by the desire to conserve as much energy as possible. Individuals aim to avoid wasting energy so they invest only the energy that is required to complete the task. The middle layer focuses on the difficulty of tasks combined with the importance of success and how this affects energy conservation. It focuses on energy investment in situations of clear and unclear task difficulty. The last layer looks at predictions for energy invested by a person when they have several possible options to choose at different task difficulties. The person is free to choose among several possible options of task difficulty. The motivational intensity theory offers a logical and consistent framework for research. Researchers can predict a person's actions by assuming effort refers to the energy investment. The motivational intensity theory is used to show how changes in goal attractiveness and energy investment correlate.