The short version:
Coming from an ACT/third-wave psychotherapy perspective, I found this book was a bit clunky and vague. While I like the idea of visually modeling issues and targeting feedback loops with treatment kernels, I found the discussion of the Extended Evolutionary Meta-Model in relation to the processes of change to be quite cumbersome and unclear.
The longer critique:
The first part of the book focuses on the processes of change- which are basically the 6 parts of the hexaflex in ACT. These made sense until they were put next to Hayes' new Extended Evolutionary Meta-Model (EEMM). The book has an important image of a grid where each of the 6 processes (plus the biophysiological and cultural levels) each have a quadrant with the 4 parts of the EEMM (which are variation, selection, retention, and context). This grid looks cool, but I ended up feeling it was somewhat of a nothing-burger.
Early on, the book has the reader choose an issue they're dealing with and then write out how each of the processes is affected within each aspect of the EEMM as they go through each process. However, the EEMM is very poorly explained, each one getting about a one paragraph definition. The pre-written examples given as a guide also make very little sense with regard to each part of the EEMM. They seem arbitrary and showed me the weakness of this new EEMM.
As I was reading, I began to believe that the EEMM were evolutionary concepts being used metaphorically in a behavioral context. However, when I actually when to a training in Philadelphia that Hayes was leading, I asked him if these were meant to be metaphorical adaptations of evolutionary concepts, and he gave a very strong "no" in response. He believed them to be actual evolutionary concepts at work in our behaviors. He basically explained that he believes that we can behave in ways that create positive evolutionary outcomes and that assessing our issues in this light would help to create evolutionarily-adaptive relationship to our inner life.
As cool as it was to talk to Hayes, I still do not think the EEMM is an accurate way of thinking about change processes (I have no gripes about the 6 given, just the EEMM component). There are certainly evolutionary principles at play in change processes, but I feel that this model is quite forced, it just doesn't fit. This isn't quite how these evolutionary principles play out. For example, the book suggests that "selection" pertains to the reasons we select affect, behavior, etc. But in evolution, selection is about the long-term reasons that traits are retained- namely reproduction and survival. There's no way for an individual to manipulate selection as an evolutionary process that leads to "adaptive" change.
I would have found it more interesting to discuss "core human yearning" which I've heard Hayes mention, as foundations of motivation (something like drives) as opposed to creating the flimsy categories into which we can plug the processes.
My other critique is that the book is clearly not third-wave or ACT specific. This took me an embarrassingly long time to realize (especially given that nothing about ACT is in the title). I have little doubt that this book was largely a diplomatic posturing of Hayes and company to allow their process-based theory access into the greater network of CBT therapists. Because of this, the book never quite says what it really wants to say. Certainly processes are at work and can be addressed even in a CBT context, but the whole idea of change processes also undermines modern CBT as we know it, and sadly this is never suggested in the book.
When I saw him speak in Philly, Hayes was not at all ambiguous about his ambition to tear down the DSM and replace decades of norm-based psychotherapy research with what he calls "idionomic" (within-person changes) research. This is a wonderful mission to be on, but I feel that the EEMM is a false flag in this battle.