Final answer:
The claim that purchase decisions are influenced solely by individual preferences is false. Both individual tastes and social and economic factors, including influence from friends and group members, shape these decisions.
Step-by-step explanation:
The statement that people's purchase decisions are most heavily influenced by individual preferences and are not really influenced by the opinions and behaviours of their friends and group members is false. People do have individual preferences, but these choices are also significantly influenced by social factors and economic circumstances. An individual's decisions, such as purchasing behaviour, are often guided not just by personal tastes but also by factors such as income, the price of goods, and social influence, including the norms and behaviours of friends and community members.
For instance, in the context of teenage clothing choices, it is not just about individual style but also about adhering to social norms, which might be influenced by a need for social acceptance among peers. A personal decision, such as marriage, might be primarily based on individual feelings, yet it is also shaped by the social acceptability of the act within a person's particular circumstances.