Personal interviews in the UPSC selection process focus on a candidate’s personality, character, and suitability for civil services. They assess attributes like leadership, communication, and analytical thinking. In contrast, psychological tests gauge a candidate's mental fitness and disposition, using standardized assessments to evaluate traits such as stress management and decision-making style. Interviews are more about subjective evaluation and interaction, whereas psychological tests yield quantifiable data about personality types, both essential in determining an aspirant's overall aptitude.