Amazing course if you're interested: Human Behavioral Biology, Stanford, 2010, by Robert Sapolsky.
I've really been enjoying these and would like to second Keri's recommendation. I am about 3/4 of the way through the lectures (so far I've watched the first dozen or so and the last half dozen). Sapolsky's course is at least as robust as any book you can read on the subject. Yes, it is a "survey", but there is a massive amount of information to process here. The course emphasizes the general principles and doesn't get lost in the details, but there are plenty of details, as well.
Sapolsky is what I would consider a "complex interactionist" on the gene/environment issue (or "nature/nurture"). I am very sympathetic to that stance . . . both the interactionism and the emphasis on its complexity. He is less keen on the kind of genetic, often "adaptionist" focus many evolutionary psychologists have (or at least had) and reinforces (at least in the lectures I've listened to so far) the significance of environmental impact on gene expression. I am still trying to decide if I take issue with this stance. Technically, I agree (as a non-expert and more psychological observer, of course). But I have felt at times that he is overemphasizing the limitations of genetic influence on behavior "to make a point". It's as if he is dialoguing with and trying to compensate "genetic determinists" who underemphasize environmental influences and variabilities.
I agree with his critiques of such "strong innatist" arguments, but my own path of entry into this subject and my own dialog is with "developmental determinists" like those who increasingly shape Jungian thought today. In the Jungian context, I find myself continuously arguing for increased attention to genetic, "instinctual", and evolutionary influences on human thought and behavior. It is a compensation of an extreme position in Jungianism and I mean to make a call for a more balanced, more scientific perspective.
Sapolsky is a real scientist and expert, but I keep imagining that many Jungians of a developmental persuasion would hear his emphasis on environmental factors on behavior and manage to miss the great importance he also places on genes. If one listens to the opinions he expresses about the relative importance of genes and environment, one hears genes downplayed. But if one more carefully pays attention to the information in his lectures, one finds Sapolsky is constantly explaining how genes and biological systems constrain human thought and behavior. More specifically, he emphasizes interaction as opposed to either factor alone . . . but I've seen interactionism misunderstood again and again in Jungian literature.
That is, the developmental Jungian norm is something like: "See, genes can't directly influence the mind without significant and specific interaction with environment, therefore genes are really not important to the development of behavior." This is a great simplification, for instance, of some of the arguments of Jean Knox, one of the most influential and often-referenced Jungian developmentalist writers who proposed reducing archetypes to "image schemas" (Knox, JAP, 2001, v.46, p.613-635). What is for me missing from arguments like those of Knox is an adequate grasp of complexity theory and the complex nature of psychic phenomena and dynamics. That a genetic influence on a behavior or function of mind is a lower order, relatively simple phenomenon in a complex cocktail of behavior does not mean it is not a highly significant factor.
One of the common characteristics of complex dynamic systems is typically referred to as the "butterfly effect". No magical properties should be attributed to the butterfly effect, nor should we suppose that every small elemental factor will have massive higher order effects on a system. What the butterfly effect expresses is the possibility that in a complex dynamic system, very small, even seemingly insignificant initial factors (e.g., the flapping of a butterfly's wings on one side of the world) CAN end up have powerful effects on the higher order aspects of the system (e.g., a hurricane on the other side of the world from the butterfly). NOT that they MUST. The theory does not propose that all hurricanes develop from the distant flapping of butterfly wings.
The butterfly effect theory is hyperbolic and metaphorical, but there are innumerable complex systems where minute elemental factors can be shown to "produce" significant higher order effects. For the purposes of a depth psychologist, it is important to understand that a genetic influence on behavior can seem minute and unrelated to the higher order behavior yet still be extremely significant to shaping that higher order behavior. The influence is complex, therefore non-linear or not directly causal or generative. Yet, in complex systems where element X is absent, the specific higher order phenomena associated with that elemental influence do not emerge.
Yes, it's a "mystery" . . . but it's also scientifically sound and measurable in many cases. None of this is to say that there are specific genetic influences that facilitate specific archetypal phenomena. We don't know how these pathways of influence might work or if they exist. The point is that, in complex systems, such butterfly effect influences are entirely possible. Moreover, they are fully compatible with Jung's quasi-philosophical, quasi-metaphysical constructions of archetypes. Maintaining a focus on complexity could allow Jungians to recognize direct roots from Jung's intuitive ideas to contemporary scientific thought. Genetic influences on behavior do not need to be downplayed or dismissed. There is simply insufficient evidence for any such dismissal or downplaying.
Additionally (and Sapolsky's course demonstrates this again and again), modern science has been showing more and more genetic influences on human behavior and thought . . . even as these influences are complex and often indirect/non-linear. We mustn't confuse indirect with insignificant.
I am not advocating a heavily biological model for archetypes. I've actually moved increasingly away from that approach. But I've been moving toward a complex interactionist approach rather than toward a developmentalist approach. In classical Jungian tradition, where two polarized views exists, one seeks for the "transcendent" Third Thing, the synthesis that emerges as a higher order phenomenon form the substratum of elemental, polarized phenomena. My objective is to break down the stuck polarization in Jungian thought on this gene vs. environment issue. It should not be a war, but a collaboration.
But in the Jungian world, the "innatist" perspective is such a huge underdog that most dissolution/deconstruction must be directed toward the developmentalist dogmas. There are only a handful (three come to mind) of Jungian writers currently advocating more "innatist" positions on archetype theory. They don't have their own Jungian society (like the SAP) with its own journal (the JAP). They are oddballs and outcasts in the Jungian world (although perhaps less odd and outcast than me). I respect the work they have been doing, but they are all a bit more "innatist" than I am. And I don't see the crossover between evolutionary psychology and analytical psychology as a fertile ground, despite many similarities or resonances. That is, neither field would benefit, in my opinion, from incorporating the ideas of the other. Jungianism may benefit from taking EP seriously and staying aware of the data it collects, but EP theories don't translate directly to archetypal phenomena. What EP tells Jungians is that genetic influences on the mind are complex and significant. How those influences might effect the archetypal phenomena we are familiar with remains a territory only Jungians are likely to explore.
What is essential is that we do not displace archetype theory from the context of evolved traits and patterned behaviors. Doing so takes us too far astray from functional models. In which case we might look at the hero archetype, for instance, and try to figure out how mother/infant interactions in the first years of life
determine the traits of the archetype. That's simply an overly reductive and confusing model that allows too many data to be discarded or misunderstood.
What may be even more challenging in Sapolsky's lectures for many Jungians is the assault on the notion of free will. Not only behavior, but something much closer to home appears to be highly constrained in Sapolsky's constructions. Namely, selfhood and the capacity to self-determine. Self-determination could be being whatever we want to be, but it could also mean willing to heal or change or transform. The capacity of an individual to heal or change (e.g., in psychotherapy) is an advanced issue in Jungian psychology. Or, at least it would be if the subject were actually dealt with with any devotion or vigilance. More often, the subject is not delved into because Jungian analysis operates on the assumption that it can and often does "work".
Despite all the time and space I've taken up on this website complaining about Jungian religiosity, anti-science and developmentalism, the most significant factor that has always separated me form the Jungian mainstream and kept me from pursuing Jungian training despite intense interest and probably aptitude is my suspicion that Jungian analysis doesn't really work. Or more accurately, that Jungian analysis doesn't work because of its specifically Jungian theories and practices. I have never been able to have much faith in the Jungian (or any psychotherapeutic) method. I have never been convinced that those Jungian patients who "get better" form their psychological diseases do so because of the method of the analysis they underwent.
I don't even really believe that any one method of psychotherapy, no matter how sophisticated, is significantly effective. I have no doubt that any methodology pales in comparative effect to the drive of the patient to heal or work through a particular issue. Perhaps it is something like dieting. One might try to lose weight by adhering to numerous diet routines . . . and these might all fail. But they all probably work for some other people. And maybe all the diets we tried failed until one day we tried Diet X, and wham! Success! But what really are the circumstances of these successes? Is it the actual method? The rules of the diet itself? Or was it more a convergence of complex circumstances and contexts that help actualize a desire to change?
This may seem cynical, especially for someone who runs a psychology website. Perhaps. I haven't given up hope in working toward a revised and more functional psychological system . . . one that might be useful for refining a clinical method. But I have yet to feel overwhelmingly hopeful that something like a "perfect" method is possible. I have been occupied primarily with trying to figure out why certain people have particular success with Jungian-like methods and languagings. Also, I am more concerned with a system that helps make the experience of being more meaningful and valuable (i,e., valuation) than with the "cure" of diseases.
The effects of psychotherapeutic work remain mysterious . . . but the mystery is fecund and continues to nourish and not be diminished. In my opinion, this is not a reason to discard it but cause to keep cultivating and exploring it.