Which interpersonal influence affects consumer behavior through reference groups?

The correct choice is social influence, which encompasses the impact of reference groups on consumer behavior. Reference groups are groups that an individual identifies with or looks to for guidance on beliefs, attitudes, and shopping behaviors. These groups can include friends, family, colleagues, or any social circle that shapes perceptions about products or brands.

When consumers consider what to purchase, they often look to these groups for cues on what is socially acceptable or desirable. For instance, a teenager may buy a particular brand of sneakers because friends at school favor that brand, indicating strong social influence.

Culture, while influential in shaping broader values and norms, does not specifically focus on the dynamics of interpersonal relationships. Family structure may affect purchasing decisions, but it refers more to the organization and roles within a family rather than the broader social groups. Personality traits influence individual behavior on a personal level, but they do not inherently factor in the external social networks that reference groups embody.