Motivation is an internal state that propels individuals to engage in goal-directed behavior. It is often understood as a force that explains why people or other animals initiate, continue, or terminate a certain behavior at a particular time. It is a complex phenomenon and its precise definition is disputed. It contrasts with amotivation, which is a state of apathy or listlessness. Motivation is studied in fields such as psychology, motivation science, neuroscience, and philosophy.

Motivational states are characterized by their direction, intensity, and persistence. The direction of a motivational state is shaped by the goal it aims to achieve. Intensity is the strength of the state and affects whether the state is translated into action and how much effort is employed. Persistence refers to how long an individual is willing to engage in an activity. Motivation is often divided into two phases: in the first phase, the individual establishes a goal, while in the second phase, they attempt to reach this goal.

Many types of motivation are discussed in academic literature. Intrinsic motivation comes from internal factors like enjoyment and curiosity; it contrasts with extrinsic motivation, which is driven by external factors like obtaining rewards and avoiding punishment. For conscious motivation, the individual is aware of the motive driving the behavior, which is not the case for unconscious motivation. Other types include: rational and irrational motivation; biological and cognitive motivation; short-term and long-term motivation; and egoistic and altruistic motivation.

Theories of motivation are conceptual frameworks that seek to explain motivational phenomena. Content theories aim to describe which internal factors motivate people and which goals they commonly follow. Examples are the hierarchy of needs, the two-factor theory, and the learned needs theory. They contrast with process theories, which discuss the cognitive, emotional, and decision-making processes that underlie human motivation, like expectancy theory, equity theory, goal-setting theory, self-determination theory, and reinforcement theory.

Motivation is relevant to many fields. It affects educational success, work performance, athletic success, and economic behavior. It is further pertinent in the fields of personal development, health, and criminal law.

Motivation is often understood as an internal state or force that propels individuals to engage and persist in goal-directed behavior. Motivational states explain why people or animals initiate, continue, or terminate a certain behavior at a particular time. Motivational states are characterized by the goal they aim for, as well as the intensity and duration of the effort devoted to the goal. Motivational states have different degrees of strength. If a state has a high degree then it is more likely to influence behavior than if it has a low degree. Motivation contrasts with amotivation, which is a lack of interest in a certain activity or a resistance to it. In a slightly different sense, the word "motivation" can also refer to the act of motivating someone and to a reason or goal for doing something. The term, motivation, comes from the Latin term movere (to move).

The traditional discipline studying motivation is psychology. It investigates how motivation arises, which factors influence it, and what effects it has. Motivation science is a more recent field of inquiry focused on an integrative approach that tries to link insights from different subdisciplines. Neuroscience is interested in the underlying neurological mechanisms, such as the involved brain areas and neurotransmitters. Philosophy aims to clarify the nature of motivation and understand its relation to other concepts.

Motivation is not directly observable but has to be inferred from other characteristics. There are different ways to do so and measure it. The most common approach is to rely on self-reports such as through questionnaires. This can include direct questions like "how motivated are you?" but may also inquire about additional factors such as goals, feelings, and effort invested in a particular activity. Another approach is based on external observation of the individual. This can involve studying behavioral changes but may also include additional methods like measuring brain activity and skin conductance.