Everyone agreed about the extraordinary potential power of symbols and metaphors. This has been an area of intense research by psychologists, linguists and philosophers; Doug Holton, for example, cites the pioneering work by George Lakoff of Berkeley. This area has also caught the interest of cognitive scientists who think about the evolution of the human mind (reflected in Tyler Volk citing the work of Steven Pinker at Harvard, who has emphasized how the capacity for “metaphorical abstraction” helps define what is unique about humans). Robert Goodrich discusses the work of another pioneer, Mark Johnson of the University of Oregon. Johnson has explored how the human capacity for abstraction is shaped by the fact that the human brain does not spend its time floating in a vat of brain soup while thinking big thoughts. Instead, it is embodied.

The power of symbols and metaphors is implicit in David Livingstone Smith writing about the difference between “A symbolically represents B” and “A is B.” For the devout Roman Catholic, wine in a particular context does not represent the blood of Christ; it is the blood. For a Hutu capable of slaughtering his neighbors without a twinge of remorse, Tutsi are not symbolic cockroaches; they are real ones. To use Smith’s term, the “metaphoricity” of metaphors can get lost in the viscera.

My piece focused on the fact that human cognition and emotions are not only embodied, they are embrained. There are neurons filled with organelles, membranes, enzymes — real in-the-trenches cells that even generate yucky metabolic waste, cells that collectively consider whether life is indeed a bowl of cherries, or if the world really is made to go round by love.

The key point of the piece was that these neurons and the brain regions in which they reside are not dedicated (“dedicated” in the sense of their sole job being to ponder symbols and metaphors from their oak-paneled studies). Instead, these neurons are working stiffs normally involved in quotidian mammalian tasks, who have gotten saddled with new functions because of the weirdness that is human brain evolution. And thus we wind up with human moral outrage potentially being so powerful because of the involvement of neurons that make you avoid eating maggot-riddled meat, or with the potential power of human empathy because of the involvement of neurons that decide that it is not a good thing that your knee hurts. In response to Tyler Volk’s question about the Landau et al. study that I discussed, I’ll bet that yes, “Don’t eat that maggot!” neurons in the insula are engaged in circumstances where our being primed about environmental pathogens makes us xenophobic.

This raised some interesting questions about whether there are other domains where our brain intermingles something approximating the sacred and the profane. Barry McKenna wonders whether there are similar neurobiological insights regarding the power of shame. I’m not sure if there has been much work in this area, but there has been concerning guilt. For example, in a recently Epublished paper (Basile et al., Human Brain Mapping, 2010; http://onlinelibrary.wiley.com/doi/10.1002/hbm.21009/pdf), the authors study the neurobiology of “deontological” guilt (guilt derived from inner values) versus “altruistic guilt” (guilt derived from the judgments of others). They found that the two types of guilt do not engage the same brain circuits. Fascinatingly, it is deontological, but not altruistic guilt which activate the insula. We may feel embarrassment or regret when we violate some rule. But there is the must greater capacity to feel gut-wrenching disgust when we violate our own deeply held values.

Nicole wondered if there something similar going on in the brain in the realm positive metaphors, when we can think of both a hot fudge sundae and a charming, wry movie comedy as being “delicious.” I think that is absolutely the case. Rather than involving disgust-ometer brain regions like the insula, there is involvement of regions that make heavy use of dopamine, a neurotransmitter central to pleasure and the anticipation of pleasure.

Superficially, you might think of a map as a pretty straightforward objective document; instead, just as winners write the history, they also draw the maps. Nat Case wonders whether there is a similar convergent neural processing of the real and the metaphorical in cartography. Is “the part of the brain that interprets map…the same part that interprets actual landscape”? This seems likely to be at least partially true, insofar as a map is an imagined version of the real world. A large body of work pertinent to this by Stephen Kosslyn of Harvard explores how the brain perceives and imagines in similar ways (for a nice review, see Kosslyn 2005 Mental images and the brain. Cognitive Neuropsychology 22, 333). For example, in one study from his group, when subjects in a functional MRI brain scanner either perceived a visual pattern or imagined it, some of the same brain regions would be activated. Now it wouldn’t be all that surprising if higher-order associational brain regions (i.e., the world of fancy places like the anterior cingulate) were activated while a person was, say, either perceiving or imagining a painting of enormous emotional significance. But the same is happening in much simpler, more nuts and bolts brain regions — similar circuits of neural activity are evoked in the primary visual cortex whether a person is looking at or imagining squiggly-shaped stimuli of particular horizontal/vertical orientations.

So the brain uses a similar trick of squeezing the concrete/literal and the metaphorical/symbolic in together in a number of different domains. Tyler Volk wonders if this reflects different brain regions independently converging on to the same solution, or whether there is a “master metaphor-making region [of the brain] that farms out the details to different brain regions as needed.” I vote for the former. The brain wonderfully reflects evolution as a tinkerer, where various brain regions independently stumbled onto similar solutions, rather than evolution as an inventor of (in this case) a brand-new top down brain region overseeing the metaphor show.

In considering the evolution of the neural underpinning of metaphors and symbols, Volk in effect wonders about the adaptive advantages of such evolution. There have been huge numbers of ways where the Darwinian fitness of an individual in a social species has been enhanced by a moment of well-timed savagery (amid there being a similar number of ways in which copies of genes are passed on thanks to moments of altruism, empathy and cooperation). David Livingstone Smith, in his own writings, has emphasized the role of self-deception in some realms where the metaphor becomes as real as the real — it truly does take some heavy duty self-deception to convince yourself that you are killing a cockroach and not an innocent human.

Again, thank you all for these comments.
Robert Sapolsky

Sapolsky begins by claiming that the human brain is not all that complex, but I feel that the fact that we have these levels of consciousness and unconsciousness makes the human brain much more complex than any other animal’s. I find it intriguing though that our neurons are exactly identical to that of even the simplest of animals like the fruit fly. If the only difference between the human brain and other animals’ brains is the number of neurons, then it makes me wonder if evolution could eventually create non-human animals as complex as humans just by increasing their neuronal connections. This also leads me to believe we can determine the innermost complexities of the human brain because the answer must lie in the number of neurons. I also believe that understanding these complexities of the brain could lead to a better human civilization because we would understand how to better communicate and deal with each other as in the Middle East peace example given by Sapolsky.

I have a few follow-up questions. First, the insula and anterior cingulate were cited as two brain regions for which there is now evidence that evolution “has duct-taped metaphors and symbols to whichever pre-existing brain areas provided the closest fit.” The phenomena were for disgust and pain, respectively. Could we have here an example of convergent evolution in the sense that a similar general pattern has evolved (either biologically or culturally) in two different brain regions? (The pattern is, namely, the use of pre-existing brain dynamics to extend conceptualization into more abstract realms.) This might be something like intra-brain convergence of a cognitively successful pattern. If so, we might expect the same trick to occur elsewhere as well, linking other, different kinds of abstraction to other, different brain regions. Is this a possibility? Or, alternatively, could there be a master metaphor-making region that farms out the details to different brain regions as needed?

Second, Steven Pinker in a recent PNAS paper says that the human ability for “metaphorical abstraction” is a second major ability (following the construction of a “cognitive niche”) that made us into who we are. This seems very much in lines with the strongest reading of Robert Sapolsky’s essay. The way I read the Pinker piece (and what makes sense to me) is that this metaphorical abstraction kicked online somewhat later than the constituent elements that went into constructing the cognitive niche, which allowed more basic cognitive capabilities (already within a specialized human realm) to eventually extend, say, reasoning that could sculpt stone tools into reasoning that could sculpt scientific theories. I wonder if RS sees as possible such a primary evolutionary role for this process of metaphorical abstraction.

Finally, I turn to Sapolsky’s discussion of the recent experiments of Landau, Sullivan, and Greenberg. They found that test subjects exhibited increased out-group rejection on a larger, abstract scale (immigration issues within the U.S.) if they had been primed by reading about invasive bacteria. I wonder if RS thinks this finding might also involve the emotion of disgust and use the insula, or whether there are other brain regions as candidates to house the development of a basic biological rejection of some kind (there are presumably other types of aversion-drives) into more abstract but powerful aversive feelings towards some “them.”

The issues Robert Sapolsky has raised in his essay are crucial to our future, as he shows in the final sections of his essay, with relevance across the scales of policy and politics in the quest for social justice and peace.

Reference:
Steven Pinker. Colloquium Paper: The cognitive niche: Coevolution of intelligence, sociality, and language. Proceedings of the National Academy of Sciences, 2010 107 (Supplement 2) 8993-8999; published ahead of print May 5, 2010, ldoi:10.1073/pnas.0914630107

In my forthcoming book Less Than Human I argue that the dehumanizing imagery found in genocidal rhetoric is intended literally. The Nazis thought of Jews literally, not metaphorically. In fact, it is because these ideas are meant literally that they possess such immense destructive power. We are tempted to see dehumanizing speech as metaphorical because it is so deeply puzzling. How could a normal human being conceive of others as rats, cockroaches or dogs (to use three historically common examples)? In the book, I argue that we pull this off in much the same way that Catholics pull of their belief in the transformation of wafer and wine into flesh and blood. We unconsciously distinguish between essence and appearance. When we dehumanize others, we think of them as possessing a human appearance but a literally subhuman essence.