The study by Steinberg and Monahan (2007) examines age differences in resistance to peer influence among adolescents. Previous research suggested that susceptibility to peer pressure follows an inverted U-shaped curve, increasing during early adolescence, peaking around age 14, and declining thereafter. However, this pattern was based on studies focusing on antisocial behavior. The authors used a new self-report instrument, the Resistance to Peer Influence (RPI) measure, to assess resistance to peer influence more generally, not just in antisocial contexts. Data from four diverse samples, including over 3,600 individuals aged 10 to 30, were analyzed. Results showed that resistance to peer influence increases linearly between ages 14 and 18, with little growth between 10 and 14 or 18 and 30. Middle adolescence is a critical period for developing the capacity to resist peer pressure. The study also found that resistance to peer influence varies by gender, ethnicity, and socioeconomic status, with girls generally more resistant than boys, and African-American individuals more resistant than Asian-American individuals. Socioeconomic status also influenced resistance, with higher SES individuals showing lower resistance at age 14 but catching up over time. The findings suggest that resistance to peer influence increases linearly during adolescence, particularly between 14 and 18, and that this pattern is consistent across different demographic groups. The study highlights the importance of considering resistance to peer influence in a broader context, beyond antisocial behavior, and underscores the need for further research on the factors influencing this capacity. The results challenge previous assumptions about the curvilinear pattern of susceptibility to peer pressure and emphasize the role of individual differences in resistance to peer influence.The study by Steinberg and Monahan (2007) examines age differences in resistance to peer influence among adolescents. Previous research suggested that susceptibility to peer pressure follows an inverted U-shaped curve, increasing during early adolescence, peaking around age 14, and declining thereafter. However, this pattern was based on studies focusing on antisocial behavior. The authors used a new self-report instrument, the Resistance to Peer Influence (RPI) measure, to assess resistance to peer influence more generally, not just in antisocial contexts. Data from four diverse samples, including over 3,600 individuals aged 10 to 30, were analyzed. Results showed that resistance to peer influence increases linearly between ages 14 and 18, with little growth between 10 and 14 or 18 and 30. Middle adolescence is a critical period for developing the capacity to resist peer pressure. The study also found that resistance to peer influence varies by gender, ethnicity, and socioeconomic status, with girls generally more resistant than boys, and African-American individuals more resistant than Asian-American individuals. Socioeconomic status also influenced resistance, with higher SES individuals showing lower resistance at age 14 but catching up over time. The findings suggest that resistance to peer influence increases linearly during adolescence, particularly between 14 and 18, and that this pattern is consistent across different demographic groups. The study highlights the importance of considering resistance to peer influence in a broader context, beyond antisocial behavior, and underscores the need for further research on the factors influencing this capacity. The results challenge previous assumptions about the curvilinear pattern of susceptibility to peer pressure and emphasize the role of individual differences in resistance to peer influence.