Final answer:
The 'Psychometric approach' by Slovic et al. involves the measurement of psychological traits through various tests, with the MMPI and MBTI being notable examples. It is part of social psychology which focuses on situational factors influencing behavior and contrasts with past methods like phrenology.
Step-by-step explanation:
Slovic et al.'s "Psychometric approach" refers to the measurement of psychological traits. This approach involves psychological assessment methods to gauge individuals' personalities and reactions. Notable instruments of this approach include the Minnesota Multiphasic Personality Inventory (MMPI), which uses true/false questions to assess various psychological conditions.
Moreover, in the field of social psychology, a major focus is on understanding how situational factors influence behavior, rather than just on personal traits or biological forces. Early attempts to understand personality, like the now-debunked science of phrenology, which attempted to correlate personality traits with skull measurements, illustrate the evolution of psychological assessment.