POPULATION VALIDITY: One limitation of Asch's experiment is its lack of population validity. The sample consisted of 123 American male students from Swarthmore College. This means the findings cannot be easily generalised to other populations, such as females or non-college students. Therefore, further research is necessary to determine whether the results would be consistent across different populations.

ECOLOGICAL VALIDITY: Another limitation is the low level of ecological validity. The line judgement task used to measure conformity was artificial and does not reflect real-life situations. Everyday examples of conformity, such as peer pressure to smoke or drink alcohol, often have more serious consequences. As a result, it is difficult to apply Asch's findings to real-world settings, and further research in naturalistic environments is needed to assess whether his results hold outside the laboratory.

LABORATORY EXPERIMENT: A strength of Asch's study is that it was conducted in a highly controlled laboratory setting. Standardised procedures and materials were used, ensuring the experiment could be replicated. This has allowed other psychologists, such as Perrin and Spencer (1981), to repeat the study in different contexts. Asch's research has therefore provided a strong foundation for further studies on conformity, contributing significantly to the field of social psychology.

ETHICAL CONSIDERATIONS: A key ethical issue in Asch's research was the use of deception. Participants were misled about the study's true purpose, as they were told it was a vision test when, in reality, it aimed to investigate conformity. This raises concerns because deception prevents participants from giving fully informed consent. Additionally, there was a lack of protection from harm, as participants were placed in a potentially stressful or embarrassing situation, which could have lowered their confidence as a result of conforming to group pressure. However, it could be argued that the use of deception was necessary to obtain valid data. Without it, participants may have shown demand characteristics, reducing the validity of the findings. Importantly, participants were fully debriefed after the study, the true aims were explained, and any psychological distress caused by the procedure was addressed.

EXAM HINT: Students may be required to explain one or more ethical limitations of Asch's investigation into conformity. For this type of question, students must explain their chosen ethical limitation in the context of Asch's research. Within the ethical considerations section, three potential issues are outlined: 1) deception, 2) lack of informed consent, and 3) lack of protection from harm.

Students may also be asked how social influence researchers can address ethical issues. In response, students could explain that researchers should fully debrief participants at the earliest opportunity, give  them the right to withdraw their data up to the point of publication, and ensure participants are not placed in situations that could cause embarrassment or discomfort.