Which word could best describe a strong effect on someone's behavior?

The word "impact" is best suited to describe a strong effect on someone's behavior because it signifies a significant and forceful influence. Impact is often used to convey how one thing can strongly affect another, indicating a force or effect that can lead to noticeable changes in actions or attitudes. In the context of behavior, an impact can lead to shifts in how a person reacts or makes decisions based on external factors, experiences, or advice.

The other words do not quite capture this meaning. "Value" refers to the importance or worth of something rather than its influence on behavior. "Lament" involves expressing sorrow or mourning, which does not relate to the concept of causing a change in behavior. "Convey" means to communicate or express something, rather than describing a strong effect. Therefore, "impact" effectively encapsulates the idea of a powerful alteration in behavior.