Final answer:
Research on the development of personality traits across the life span has revealed that the Big Five personality factors are relatively stable traits that exist across ethnicities, cultures, and ages. Personality traits have a genetic basis and are influenced by environmental factors, including culture. Personality development takes place throughout the lifespan, with some traits increasing or decreasing slightly with age.
Step-by-step explanation:
The research on the development of personality traits across the life span has revealed several important findings. Firstly, the Big Five personality factors (conscientiousness, agreeableness, neuroticism, openness, and extraversion) have been identified as relatively stable traits that exist across ethnicities, cultures, and ages. Secondly, personality traits have a genetic basis and are influenced by environmental factors, including culture. Lastly, researchers have found that personality development takes place throughout the lifespan, with some traits increasing or decreasing slightly with age.