One issue of validity in this research is demand characteristics. Participants may notice cues in the situation, such as the confederate’s clothing or the request to sign-up for charity, and change their behaviour to appear helpful rather than acting naturally. This means the results might reflect participants trying to please the researcher instead of genuine willingness to donate, lowering the interval validity of the study. To reduce this problem, a single-blind design could be used, where participants are unaware of the true purpose of this research. This would prevent them from guessing the hypothesis and behaving differently, improving the validity of the findings
