This is the result of several factors:
The complexity of human nature, where disciplines and points of view have to be added in order to explain behaviour
The changes in the context in which consumers live, which triggers the need to revisit theories
The relative youth of the discipline that studies consumer behaviour
Think, for example, of the old discipline of Concept Writing, which still survives. It has a three-paragraph structure of 1) insight with the tension to be resolved, 2) benefit provided by the brand and 3) reason to believe. Well, the “tension to resolve” is a concept from Joannis (personality school). The “benefit” clearly sounds like Reeves' USP (product school), and the “Reason Why” comes from Hopkins (product school).
At a broader level, the companies that have the most sophisticated marketing are able to synthesise what we know about rational and irrational consumer behaviour, statistical analysis of consumer panel data (with its “double jeopardy...), understand the point of sale to help that consumer who buys in fast mode, understand the positioning of their brands in the minds of consumers... What they do is the sum of the best we have learned over the decades.
The behaviour and thinking of companies like Procter & Gamble, one of the organisations with the longest tradition in branding, is interesting. In the book "Playing to Win" by the company's two-time CEO A.G. Lafley, he talks about the different branding doctrines that followed in his company. Lafley talks about the different brand-building doctrines that followed in his company. The "Brand Building Framework - BBF": version 1.0 appeared in 1999, 2.0 in 2003, 3.0 in 2006 and 4.0 in 2021. Lafley prefaced the Lovemarks book by Kevin Roberts, a clear exponent of 2nd wave branding theories, just at the time of his BBF 3.0. Years later, at the time of BBF 4.0, we see that P&G is a patron of the Ehrenberg Bass Institute and has adopted some of its ideas (3rd wave). Each BBF was not an amendment of the previous one but a genuine move towards best practices in marketing. We, therefore, see the lack of dogmatism and the flexibility for the evolution of the most sophisticated companies. We are fully convinced that today, marketing in the best companies follows a fourth-wave school, where syncretism is what is practised.
In part 2, we will focus on the implications of syncretism on brand image measurement.
 Other authors, such as Iolanda Casalà in her doctoral thesis or David Fernández in his book "Mecanismos estratégicos de publicidad" make different groupings, in his case, of 3 groups. Our proposal coins a new fourth wave.
 In reality, Byron Sharp is popularising the ideas that statistician Andrew Ehrenberg explored years earlier, especially "The Dirichlet: A Comprehensive Model of Buying Behaviour", (Goodhardt, Ehrenberg and Chatfield, 1984). Byron Sharp is the most visible face of the Ehrenberg-Bass Institute for Marketing Science. It is interesting to reflect on authorship vs. popularisation of ideas. The history of marketing is littered with examples where interesting ideas are repackaged by characters with an eye for selling and often a lot of ego. For example, Reeves, with his USP, is rephrasing and "marketing" what Mcjunkin described in his "Dominant Idea". Ogilvy did something similar with the "Brand Image" first described by Pierre Martineau, moving it from theory to practice and, along the way, appropriating it. As professionals in the world of insights, these facts give food for thought about the world of "selling ideas" to which we all dedicate ourselves.
. This term was also introduced into marketing by Ehrenberg. It is described as the phenomenon whereby brands with lower market share also have fewer purchases and less consumer loyalty. In other words, "less popular" brands not only have fewer buyers, but their buyers are less loyal than those of more popular brands. This is directly related to what was mentioned in relation to the physical and mental availability of the third wave.