The primary reason for why, as a marketer, you should give value to the learning and understanding of psychology is because both fields have been intertwined for a long time — dating back to the days of Edward Bernays. Bernays' was credited to being the father of Public relations as he had significant influence from his the nephew of the world famous neurologist, Sigmund Freud. This relationship helped him find that information drove behavior when he was in charge of World war one propaganda for the United States government. He also used his uncles teaching to the develope able how to use psychological triggers to shift consumers from a more utilitarian focused view on shopping culture to more hedonic centric views. This idea and many other psychology-based approaches were used in campaigns to get a more scientific explanation for why people react specific ways to specific tactics. These practices have spanned across different methods like public relations, advertising, and of course, marketing.
If the previous point did not convince you of the importance of psychology, maybe this will help sell you on it. The future of marketing is headed towards not only a more digital path but also a more scientific one too. This psychological approach to marketing gaining popularity across the industry and is being practiced by a lot of companies on the west coast. One example of this human behavior focus is eye-tracking technology that can follow the movement of someone's eye while the view promotion of some sort. This advancement is helping marketers better design what goes on particular promotions and even how it is placed out.
Psychology is something that has had a deep relationship with the world of marketing. By having an understanding of how the human mind works, you can develop some great work that has an immense amount of impact on your customer.