What factor is essential for an individual's motivation to act?

The strength of the need is crucial as it drives an individual's motivation to act. When a need is strong, it creates an internal pressure to fulfill that need, which can lead to persistent efforts and actions toward achieving a specific goal. For example, a person who has a strong desire for career advancement is more likely to seek out opportunities for professional development, take on challenging projects, or network effectively. This inherent motivation stems directly from the intensity of their need rather than external factors, which makes it a fundamental element in the motivation process.

On the other hand, while expectations of recognition, peer influence, and supervision can play roles in motivation, they are generally considered as external factors. They may enhance or diminish motivation but do not fundamentally create it. The internal drive caused by the strength of a need is often what ultimately propels an individual to take action.