Final answer:
The statement about the established presence and influence of personality traits in psychology is true. The field has moved from identifying numerous specific traits to understanding personality as a blend of broader dimensions influenced by both genetics and environment.
Step-by-step explanation:
The assertion that no doubt exists about the presence and predictive power of individual differences in personality traits is considered to be TRUE. The study of personality psychology has evolved significantly over the years. Initially, trait theorists like Gordon Allport suggested numerous traits to describe human behaviors, which he categorized into cardinal, central, and secondary traits. Later models, such as the Five Factor Model, streamlined these concepts into broader dimensions of conscientiousness, agreeableness, neuroticism, openness, and extraversion, which are relatively stable across an individual's lifespan and show genetic influences.
Moreover, personality traits are recognized for their role in individual behavior as a complex interplay between situational and dispositional factors, expanding upon the works of theorists like Raymond Cattell. Current research also considers biological and environmental influences on personality, understanding that both inherent genetic factors and culture/environment contribute to the development of one's personality. This blend of dispositionism and situationism reflects a layered and comprehensive approach to personality psychology today.