This poster summarizes the development of the concept of the consumer from the intersection of marketing and psychology between the late 19th century and early 21st century. It describes how marketing emerged as a distinct academic discipline in the early 1900s in the US as industrialization and capitalism grew. Pioneering psychologists then contributed to understanding consumer behavior through experimental research. The formation of the Consumer Psychology Division in the APA in the 1960s further legitimized consumer psychology as a field. The poster analyzes how psychological theories and findings influenced how marketing conceptualized consumers over this period, such as seeing them as decision-makers, influenced by advertising, and later as members of market segments.