Which psychological phenomenon involves making substantial effort to justify a modest goal upon realizing the inconsistency in one's beliefs?

The phenomenon described in the question is best captured by effort justification, which refers to the cognitive process in which individuals rationalize the effort and energy they invest in pursuing a goal or undertaking. When a person dedicates significant resources to a relatively modest goal, they may experience a sense of dissonance, especially if the outcome does not align with their expectations. As a result, they will justify their efforts to resolve this inconsistency and bolster their belief that the goal was indeed worthwhile.

This concept is integral to understanding how people cope with feelings of inadequacy or frustration when outcomes do not meet their initial hopes, leading them to persuade themselves that the effort was meaningful or significant. Essentially, effort justification helps restore balance in one's beliefs and self-perception.

Other options do not specifically address the situation in the question. Cognitive dissonance is a broader term that describes the discomfort individuals feel when holding conflicting beliefs or behaviors. Confirmation bias pertains to seeking out information that supports one's existing beliefs, rather than addressing inconsistencies. Actor-observer bias refers to the tendency to attribute one’s own actions to external factors while attributing others' actions to their character or personality.