Final answer:
Large-scale studies on the effect of birth order on personality characteristics have not shown consistent patterns or significant influences on personality traits.
Step-by-step explanation:
Large-scale studies on the effect of birth order on personality characteristics have not shown a clear and consistent pattern of personality differences based on birth order. While some researchers have found small differences in certain traits based on birth order, others have found no significant influence of birth order on personality. It is important to note that birth order is just one factor among many that can influence personality development, and individual differences within families can also have a significant impact.