The decision model assumes that purchase decisions do not occur in a vacuum. Rather, they occur in real time and are affected by other stimuli, including external environmental stimuli and the consumer's momentary situation. The elements of the model include: interpersonal stimuli (between people) or intrapersonal stimuli (within people), environmental stimuli and marketing stimuli. Marketing stimuli include actions planned and carried out by companies, whereas environmental stimuli include actions or events occurring in the wider operating environment and include social factors, economic, political and cultural dimensions. In addition, the buyer's black box includes buyer characteristics and the decision process, which influence the buyer's responses.