Is Darwin due for an upgrade?

I would recommend you have a look at this article by Douglas Erwin (PDF here) on the prospects of a paradigm shift in evolutionary biology. Here are some clips:

...constructed from the 1930s to 1950s by early geneticists, paleontologists and others..the modern synthesis...holds that mutations to DNA create new variants of existing genes within a species. Natural selection, driven by competition for resources, allows the best-adapted individuals to produce the most surviving offspring. So adaptive variants of genes become more common...Computer simulations have shown how selection can produce a complex eye from a simple eyespot in just a few hundred thousand years.

In the past few years every element of this paradigm has been attacked. Concerns about the sources of evolutionary innovation and discoveries about how DNA evolves have led some to propose that mutations, not selection, drive much of evolution, or at least the main episodes of innovation, like the origin of major animal groups, including vertebrates.

Comparative studies of development have illuminated how genes operate, and evolve, and this places less emphasis on the gradual accumulation of small genetic changes emphasized by the modern synthesis. Work in ecology has emphasized the role organisms play in building their own environments, and studies of the fossil record raise questions about the role of competition. The last major challenge has argued for a hierarchical view of evolution, with selection occurring at many levels, including between species.

The Achilles’ heel of the modern synthesis.. is that it deals primarily with the transmission of genes from one generation to the next, but not how genes produce bodies. The recent discoveries in the new field of evolutionary developmental biology, or evo-devo, that the gene Pax-6 controls the formation of eyes in mice and humans, Nkx2.5 heart formation, and a suite of other genes the formation of the nervous system, has provided a means to investigate the genetic and developmental mechanisms influencing how the form of organisms has evolved, not just their genes.

Core gene networks appeared long ago that locked development onto a certain path (an example being a kernel of five key genes regulating development of the gut that appeared 500 million years ago). These events, small and large, limit the range of possibilities on which natural selection can act...just as the erosive power of a river changes the future options for the course of the river, so evolution itself changes future evolutionary possibilities.

The first cyanobacteria turned carbon dioxide into oxygen and set off a revolution that completely changed the chemistry of the oceans and atmosphere. Most species modify their environment and this often changes how selection affects them: they construct, at least in part, their own environment. As evolutionary biologists we have little understanding of what these processes mean for evolution.

Does all this add up to a new modern synthesis? There is certainly no consensus among evolutionary biologists, but development, ecology, genetics and paleontology all provide new perspectives on how evolution operates, and how we should study it. None of these concerns provide a scintilla of hope for creationists, as scientific investigations are already providing new insights into these issues. The foundations for a paradigm shift may be in place, but it may be some time before we see whether a truly novel perspective develops or these tensions are accommodated within an expanded modern synthesis.

A social/musical at Twin Valley

Every year or two my partner Len and I host a social afternoon on a Sunday from 3-6 at our home on Twin Valley Road in the Town of Middleton, Wisconsin. It is a stone schoolhouse built in 1860, converted to a residence by a Frank Lloyd Wright lieutenant named Herb Fritz. Len (who is a gourmet cook) provides appetizers and Hors D'oeuvres and I do some piano playing either by myself or with a string chamber group. Here are two pictures from Sunday July 1. (By the way, blog posts are going to be spotty this holiday week).



After the Chopin B minor Scherzo...


.....Deric with his first (1969, Ann Gordon Walker) and last (1995, Dima Klenchin) postdoctoral students

Science of the Soul

I recommend this engaging article by Cornelia Dean (PDF here) on how evolutionary biologists and cognitive scientists are discovering physical bases for the feelings from which moral sense emerges — not just in people but in other animals as well.

As is illustrated by the three Republican presidential candidates that raised their hands during a debate when asked 'Is there anyone who does not believe in evolution?,' challenges to the uniqueness of humanity in creation are just as alarming as the Copernican assertion that Earth is not the center of the universe,

Face perception by distributed cortical networks.

Continuing to pass along material from talks given at the recent ASSC meeting, here is the abstract and some figures from an interesting bit of work on face perception (PDF here).

Face perception elicits activation within a distributed cortical network in the human brain. The network includes visual (‘‘core’’) regions, as well as limbic and prefrontal (‘‘extended’’) regions, which process invariant facial features and changeable aspects of faces, respectively. We used functional Magnetic Resonance Imaging and Dynamic Causal Modeling to investigate effective connectivity and functional organization between and within the core and the extended systems. We predicted a ventral rather than dorsal connection between the core and the extended systems during face viewing and tested whether valence and fame would alter functional coupling within the network. We found that the core system is hierarchically organized in a predominantly feedforward fashion, and that the fusiform gyrus (FG) exerts the
dominant influence on the extended system. Moreover, emotional faces increased the coupling between the FG and the amygdala, whereas famous faces increased the coupling between the FG and the orbitofrontal cortex. Our results demonstrate content-specific dynamic alterations in the functional coupling between visuallimbic and visual-prefrontal face-responsive pathways.

Face perception elicits activation within a distributed cortical network. Axial sections, taken from a representative subject, illustrate activation within the core (IOG-inferior occipital gyrus, FG-fusiform gyrus, STS - superior temporal sulcus) and extended (AMG-amygdala, IFG-inferior frontal gyrus, OFC-orbitofrontal cortex) systems. Coordinates are in the Talaraich space. L 5 left, R 5 right.


(click to enlarge) Alterations in effective connectivity within the core and the extended systems induced by all faces, emotional faces, and famous faces. Black connections indicate significant regional effects, red connections indicate significant bilinear effects, and dotted lines indicate non-significant effects.

A Schubert Scherzo

....from his Sonata No. 10. I thought I might slip in another of my brief recordings, a bit of relief from the heavy neuroscience...

Role of the amygdala in visual awareness.

There have been several reports that subliminal stimuli (such as flashing a picture of an angry face for 33 msec) can activate the amygdala even though the subject is unaware of the stimulus. Pessoa presented work at the recent ASSC meeting using more rigorous criteria for behavioral performance that suggests, to the contrary, that visibility or attention is required for the expression of the effect of valence on early visual processing (even as early as the 'automatic' parallel processing in V1.) A PDF of a recent Pessoa et al. article is here, and PDF of commentary on this work by Duncan and Barrett here). This work:

...shows that amygdala responses depend on visual awareness. Under conditions in which subjects were not aware of fearful faces flashed for 33 ms, no differential activation was observed in the amygdala. On the other hand, differential activation was observed for 67 ms fearful targets that the subjects could reliably detect. When trials were divided into hits, misses, correct rejects, and false alarms, we show that target visibility is an important factor in determining amygdala responses to fearful faces. Taken together, our results further challenge the view that amygdala responses occur automatically.

Duncan and Barrett, in their commentary, suggest

...that the amygdala is acting to increase neural activity in the fusiform gyrus, thereby increasing the likelihood that visual representations that have affective value reach awareness. The psychological consequence is that a person’s momentary affective state might help to select the contents of conscious experience.

Visual awareness is associated with amygdala activation. In the Pessoa et al. study, participants viewed backwardly masked images of faces that depicted fear, presented for either 33 ms or 67 ms. All participants showed greater amygdala activation when viewing fearful faces that were presented for 67 ms, compared with faces that depicted neutral expressions. (a) Pessoa et al. found an increase in amygdala activation (as well as fusiform gyrus activation, which is not shown in the figure) only among those participants who showed objective awareness of 33 ms presentations of faces that depicted fear. (b) Participants who did not show objective awareness did not have significant increases in amygdala activation. Given the excitatory projections from the amygdala to the ventral visual stream, this finding suggests that the amygdala enhances visual awareness for objectives with affective value.

Perception Without a Perceiver

Rafeal Malach gave an interesting talk at the recent ASSC meeting (PDF of article here) on work from his group that he thinks:

challenges the conventional models of human perception, which assume that sensory experience involves a critical interplay between activity in sensory cortex representing the stimulus and pre-frontal cortex which serves as an “observer” system- receiving and interpreting the patterns of activity originating in posterior, sensory cortex.

In an fMRI study in which individuals were exposed to a highly engaging popular movie they find:

a surprisingly robust and wide-spread activation of most of the posterior part of the brain- which was remarkably “synchronized” across individuals watching the same movie. These results attest to the massive engagement of sensory cortex by naturalistic sensory stimuli. However, in contrast to this wide-spread activation in sensory cortex- we have found a remarkably little activation in frontal areas of the brain (Fig. 1).

Fig. 1 Brain activation during repeated movie presentation. Yellow regions show highly activated areas in posterior, sensory cortex. Note lack of activation in frontal areas and in the intriguing “intrinsic” islands in posterior cortex (arrows).

To examine this issue, and also to start mapping in more detail the functional organization of the various networks of pre-frontal cortex:

we have conducted a series of experiments in which we mapped brain activity during tasks that were explicitly targeted at eliciting “self-related” brain activity- such as introspection to visual and auditory modalities, or self-judgment evaluations. Although these were high level cognitive tasks of extreme complexity- our results show a remarkably consistent pattern of activity focused primarily on pre-frontal cortex (see yellow patches in figure 2)...The critical question was now- how do these areas behave when the task shifts to a purely perceptual one? The results were clear cut- the activity shifted now to a different set of areas- located more posteriorly in sensorymotor
cortex (green patches in fig. 2).

Fig. 2 Comparing brain activity during reflective self-related tasks and during intense perception. Prefrontal areas (yellow patches) showed significant activation during self-related introspection and self judgment tasks. However a completely different and highly segregated network of more posterior areas were active during engaging perceptual tasks (green patches). No overlap was found between the two networks, and the prefrontal cortex was actually inhibited during intense perception. The results clearly rule-out the need for an “observer” function in self-related
cortex during perception.

The results are:

... actually compatible with the strong intuitive sense we have of 'losing our selves' in a highly engaging sensory-motor act (such as watching a movie). They are intriguingly reminiscent of recurrent eastern philosophical themes which emphasize the ‘silencing' of the self during intense engagement with the outside world.

The Science of Gaydar

This is the title of an excellent article in New York Magazine, mentioned also in MindHacks.

Language without recursion...

My april 26 post dealt with a New Yorker article describing the work of Dan Everett on the language of an Amazon people which he interprets as showing humans can invent language without recursion. At edge.org there is now an interesting further conversation between Everett, Steven Pinker, and Robert Van Valin.

Esthetic experience and mirror neurons - motion, emotion and empathy

David Freedberg (Art History, Columbia Univ.) and Vittorio Gallese (Neuroscience, Parma) offer an interesting perspective on possible relationships between mirror neuron systems and artistic experience. Here is their abstract (and PDF of article is here.), followed by some of their illustrations.

The implications of the discovery of mirroring mechanisms and embodied simulation for empathetic responses to images in general, and to works of visual art in particular, have not yet been assessed. Here, we address this issue and we challenge the primacy of cognition in responses to art. We propose that a crucial element of esthetic response consists of the activation of embodied mechanisms encompassing the simulation of actions, emotions and corporeal sensation, and that these mechanisms are universal. This basic level of reaction to images is essential to understanding the effectiveness both of everyday images and of works of art. Historical, cultural and other contextual factors do not preclude the importance of considering the neural processes that arise in the empathetic understanding of visual artworks.

Figure 1. Embodied simulation in esthetic experience: actions. The sense of exertion, which Michelangelo intended his figures to show as they struggle to escape from the block of stone, is effectively conveyed to the spectator. Michelangelo, Slave called Atlas, Florence, Academia (ca. 1520–1523), marble © Scala/Art Resource, NY.

Figure 2. Embodied simulation in esthetic experience: empathy for pain. The viewing of images of punctured or damaged body parts activates part of the same network of brain centers that are normally activated by our own sensation of pain, accounting for the feeling of physical sensation and corresponding shock upon observation of pressure or damage to the skin and limbs of others. Goya, Que hay que hacer mas? (What more is there to do?), plate 33 from Los Desastres de la Guerra (Disasters of War), etching, Biblioteque Nationale, Paris, France © Bridgeman-Giraudon/Art Resource, NY.

Figure 3. Embodied simulation in esthetic experience: implied gestures of the artist. The gestures that are only implicit in the marks on these works of art are corporeally felt by their spectators. (a) Jackson Pollock, Number 14: Gray (1948), enamel over gesso on paper, Yale University Gallery, The Katharine Ordway Collection © 2004 The Pollock-Krasner Foundation/Artists Rights Society (ARS), New York. (b) Lucio Fontana, Concetto Spaziale ‘Atteza’ (‘Waiting’) (1960), canvas, Tate Gallery, London © Tate Gallery, London/Art Resource, NY/ Fondazione Lucio Fontana, Milano.

Figure 4. The mirror neuron system in monkeys and humans. (a) Activation of the area F5 mirror neuron during motor-act observation. (b) Activation of the area F5 mirror neuron during action execution. For both conditions, six consecutive rasters (spike recordings) during six consecutive trials are shown. The arrows indicate the onset of observed and executed grasping. (a) and (b) modified, with permission, from Ref. [60]. (c) Somatotopy of premotor and parietal cortices as revealed by fMRI during action observation. Activation foci are projected on the lateral surface of a standard brain (MNI). Red, activation during the observation of mouth grasping; green, activation during the observation of hand grasping; blue, activation during the observation of foot kicking. Overlap of colors indicates activation foci present during observation of actions made by different effectors.

Greetings from Las Vegas and the ASSC meeting

This is the last day of the annual meeting of the Association for the Scientific Study of Consciousness. I'm going to wait and work up a few posts on some of what I think is the most interesting material over the next period of time. Las Vegas is beyond belief.... like apocalypse now.... it will take weeks for the sensory overload to fade away. Here is the Eiffel Tower in Paris, Las Vegas, and the view of the Bellagio fountains from my lunch in its restaurant (the only peaceful and quiet place in the city I found) ....

The most popular posts on MindBlog

I subscribe to a service offered at feedburner.com that lets you see details of the traffic on your blog. I am passing on the titles of the five postings that it indicates have been read the most.

Watching a computer "be nice" activates our brain's agency and goal detectors

A new desciprtion of our inner lives…

A neural network that shares a common genetic origin with human intelligence.

Social Networks - the twenty-first century science?

The pianist in the mirror - human mirror neuron systems for motor learning

New steps in memory consolidation

Paz et al show how the hippocampal-medial prefrontal cortex interactions thought to support memory consolidation are enhanced by correlated activities in regions around the hippocampus. Their introduction gives a quick summary of known steps in memory consolidation which provides context for their experiment, here are some edited clips:

The hippocampus plays a time-limited role in the formation of declarative memories, with memories gradually becoming independent of the hippocampus over time. It is believed that these remote memories are gradually transferred from the hippocampus to the neocortex for long-term storage..investigations indicate that the medial prefrontal cortex (mPFC) is critical for the consolidation of hippocampal-dependent memories. In trace-conditioning tasks for instance, hippocampal lesions cause a severe deficit when made soon after training, but not after a month, whereas mPFC lesions produce the opposite pattern of impairments. ...The role of mPFC activity in memory formation remains unclear. One possibility is that mPFC affects the transfer of hippocampal activity toward the neocortex. Consistent with this possibility, the mPFC projects to the rhinal cortices, the main route for impulse traffic into and out of the hippocampus...the present study was undertaken to test the idea that the mPFC influences memory formation by modulating interactions between the neocortex and hippocampus at the level of the rhinal cortices. To this end, we examined the relative timing of unit activity in the mPFC, PR, and ER cortices during the acquisition of a trace-conditioning task.

And, here is the abstract of the paper:

Much data suggests that hippocampal–medial prefrontal cortex (mPFC) interactions support memory consolidation. This process is thought to involve the gradual transfer of transient hippocampal-dependent memories to distributed neocortical sites for long-term storage. However, hippocampal projections to the neocortex involve a multisynaptic pathway that sequentially progresses through the entorhinal and perirhinal regions before reaching the neocortex. Similarly, the mPFC influences the hippocampus via the rhinal cortices, suggesting that the rhinal cortices occupy a strategic position in this network. The present study thus tested the idea that the mPFC supports memory by facilitating the transfer of hippocampal activity to the neocortex via an enhancement of entorhinal to perirhinal communication. To this end, we simultaneously recorded mPFC, perirhinal, and entorhinal neurons during the acquisition of a trace-conditioning task in which a visual conditioned stimulus (CS) was followed by a delay period after which a liquid reward was administered. At learning onset, correlated perirhinal-entorhinal firing increased in relation to mPFC activity, but with no preferential directionality, and only after reward delivery. However, as learning progressed across days, mPFC activity gradually enhanced rhinal correlations in relation to the CS as well, and did so in a specific direction: from entorhinal to perirhinal neurons. This suggests that, at late stages of learning, mPFC activity facilitates entorhinal to perirhinal communication. Because this connection is a necessary step for the transfer of hippocampal activity to the neocortex, our results suggest that the mPFC is involved in the slow iterative process supporting the integration of hippocampal-dependent memories into neocortical networks.

Horniness of male mice - up and down with estrogen

Here is the abstract from Taziaux et al. Might this tempt pharmaceutical companies to go for a human male equivalent?

Estrogens are classically viewed as hormones that bind to intracellular receptors, which then act as transcription factors to modulate gene expression; however, they also affect many aspects of neuronal functioning by rapid nongenomic actions. Brain estrogen production can be regulated within minutes by changes in aromatase (estrogen synthase) activity as a result of calcium-dependent phosphorylations of the enzyme. To determine the effects of rapid changes in estrogen availability on male copulatory behavior, we mimicked in male mice the rapid upregulation and downregulation of brain estrogen concentration that should occur after inactivation or activation of aromatase activity. A single injection of different aromatase inhibitors [Vorozole, 1,4,6-androstatrien-3,17-dione (ATD), or its metabolite 17-OH-ATD (1,4,6-androstatrien-17ß-ol-3-one)] almost completely suppressed male sexual behavior (mounts and intromissions) expressed 10–20 min later by C57BL/6J mice but did not affect behavior in aromatase knock-out (ArKO) mice, activated by daily injections of estradiol benzoate, thereby confirming the specificity of the behavioral inhibition observed in wild-type mice. The rapid ATD-induced inhibition was reversed by the simultaneous injection of a large dose of estradiol. A single injection of estradiol to ArKO mice also activated male sexual behavior within 15 min. Thus, rapid increases or decreases in brain estrogen concentrations are followed within minutes by corresponding changes in male sexual behavior. Sexual behavior can thus be used to monitor changes in local estrogen concentrations and analyze the mechanisms mediating the rapid decline in estrogen signaling that takes place after inhibition of estrogen synthesis.

Debunking Phrenology - oscillating networks control behavior

Robert K. Night writes a perspective in Science (PDF here) on how neural networks support goal-directed behavior:

Systems neuroscience aims to understand how billions of neurons in the mammalian brain support goal-directed behavior, such as decision making. Deciphering how individual neurons respond to sensory inputs or motor decisions has focused on delineating the neural basis of these processes in discrete regions of the brain's cortex, and has provided key insights into the physiological basis of behavior. However, evidence from neuropsychological, electrophysiological, and neuroimaging studies in humans has revealed that interactions between widespread neural regions in the brain underlie fluid, organized behavior.

He then summarizes work reported in three papers to:

...unravel the details of these interactions by assessing the simultaneous activity of neurons in multiple sites of the mammalian brain. The studies show that network interactions among anatomically discrete brain regions underlie cognitive processing and dispel any phrenological notion that a given innate mental faculty is based solely in just one part of the brain.
...Taken together, the three papers indicate that top-down signals between brain regions regulate the flow of information and that distributed neural networks that use oscillatory dynamics support a broad spectrum of neural processing and behavior. The results in cats and monkeys also nicely parallel findings in humans...this particular coupling mechanism is used to delineate task-specific network activity

Deric off to Magic and Consciousness in Las Vegas - ASSC meeting

I'm taking off now for the annual meeting of the Association for the Scientific Study of Consciousness meeting in Las Vegas, June 22-25, at the Imperial Palace Hotel on the Strip. The program looks fascinating, with many luminaries in the field of consciousness studies. A special feature is a show by famous magicians and illusionists illustrating the psychological and perceptual tricks they employ.

Perhaps I'll have time to give you some "dispaches from the front." Otherwise, I'll try to present some bon-bons from the meeting on this blog when I get back.

Most popular consciousness papers for May

From the Assoc. for the Scientific Study of Consciousness eprint committee, the five most popular (i.e. most downloaded from the eprint archive) papers of May 2007:

1. Sagiv, N. and Ward, J. (2006) Crossmodal interactions: lessons
from synesthesia. Progress in Brain Research,155. (1428 downloads from
22 countries). http://eprints.assc.caltech.edu/224/.
2. Windt, J.M. and Metzinger, T. (2006) The philosophy of dreaming and
self-consciousness: What happens to the experiential subject during
the dream state? In: The new science of dreaming (1063 downloads from
22 countries). http://eprints.assc.caltech.edu/200/.
3. Block, N. (2007) Consciousness, Accessibility and the Mesh between
Psychology and Neuroscience. Behavioral and Brain Sciences,
forthcoming. (991 downloads from 18 countries).
http://eprints.assc.caltech.edu/261/
4. Robbins, S. E (2006) Bergson and the holographic theory of mind.
Phenomenology and the Cognitive Sciences, 5. (984 downloads from 19
countries). http://eprints.assc.caltech.edu/206/.
5. Koriat, A. (2006) Metacognition and Consciousness. In: Cambridge
handbook of consciousness. Cambridge University Press, New York, USA.
(941 downloads from 23 countries).
http://eprints.assc.caltech.edu/175/

Further information: http://eprints. assc.caltech.edu

Brain responses revealing motives for charitable donations.

A recent study by Harbaught et al. finds that three very different things—monetary payoffs to oneself, observing a charity get money, and a warm-glow effect related to free choice—all activate similar neural substrates. Here is their abstract, PDF of article is here.

Civil societies function because people pay taxes and make charitable contributions to provide public goods. One possible motive for charitable contributions, called "pure altruism," is satisfied by increases in the public good no matter the source or intent. Another possible motive, "warm glow," is only fulfilled by an individual's own voluntary donations. Consistent with pure altruism, we find that even mandatory, tax-like transfers to a charity elicit neural activity in areas linked to reward processing. Moreover, neural responses to the charity's financial gains predict voluntary giving. However, consistent with warm glow, neural activity further increases when people make transfers voluntarily. Both pure altruism and warm-glow motives appear to determine the hedonic consequences of financial transfers to the public good.

Figure: Neural response in the ventral striatum to mandatory payoffs for the subject (yellow), the charity (blue), and both (green). (To test for the pure altruism and warm-glow motives, they used functional magnetic resonance imaging while subjects played a dictator game. Subjects received $100 and then made decisions about whether or not to give money to a local food bank. They also observed mandatory, tax-like transfers of their money to the food bank.)

They suggest that:
...This result supports arguments for a common "neural currency" of reward and shows that this model can be applied not just to choice over money, risk, and private consumption goods, but also to more abstract policy choices involving taxation and charitable giving. Our results are also important for understanding why people give money to charitable organizations. First, these transfers are associated with neural activation similar to that which comes from receiving money for oneself. The fact that mandatory transfers to a charity elicit activity in reward-related areas suggests that even mandatory taxation can produce satisfaction for taxpayers. A better understanding of the conditions under which taxation elicits "neural rewards" could prove useful for evaluating the desirability of different tax policies.

A consciousness researcher database.

The Mind Science Foundation website provides a consciousness researcher database that you might use to look up some of the notables in the field. It also provides a number of other useful links.

Is there wisdom in disgust? - moral psychology

Dan Jones writes an interesting essay in a recent issue of Science (PDF here) on how work in evolutionary theory, moral philosophy, and neuroscience casts doubt on the idea that disgust embodies a deep-seated wisdom. Instead it provides an emerging portrait of an evolutionarily constrained emotion that is a poor guide to ethical action. Here are some edited clips from his article:

Although the experience of disgust feels primal, the emotion does not seem to be widespread in other animals. Many species exhibit distaste in response to the sensory properties of food — such as sourness and bitterness — and a monkey, cat or human infant might spit out something disagreeable. But only humans beyond infancy will reject food on the basis of where it might have been and what it might have touched.

A clue is the language of moral indignation itself...All cultures and languages that we have studied have at least one word that applies both to core disgust (cockroaches and faeces) and also to some kind of social offence, such as sleazy politicians or hypocrites...people labelled as disgusting in this way evoke fears of contamination just as rotting food does...disgust drives some moral judgements, but ... they are mainly those relating to behaviour that involves bodily fluids or contact — gay sex, for instance — rather than more abstract issues.

Clues suggest a physiological reality for moral disgust. Whereas anger pushes the heart rate up, being viscerally disgusted makes it drop. Experiments done by Haidt and Sherman showed
... people hooked up to a heart monitor video footage of morally negative but not viscerally disgusting behaviour, such as an American neo-Nazi meeting. The participants said that the video triggered disgust and anger, and on average their heart rates fell, not rose. What's more, those who reported increased clenching in their throat had a greater drop in heart rate, making the link with core disgust look stronger.
...this is the first physiological evidence that socio-moral disgust really is disgust and not just metaphor or anger.

Brain imaging studies might also point to an overlap between core and moral disgust... Moll...used magnetic resonance imaging (MRI) to monitor the flow of blood in the brains of 13 healthy adult volunteers as they mulled over situations evocative of core disgust and those that elicit self-reported moral disgust or indignation. He found that core and moral disgust recruit overlapping brain areas, particularly the lateral and medial orbitofrontal cortex, suggesting that the emotions are related. These regions of the brain are activated by unpleasant sensory stimuli, and they connect with other emotion-related areas, such as the amygdala.

Evolution suggests that the human moral faculty — the psychological systems that make judgements about right and wrong, what's permissible and what isn't — was cobbled together from pre-existing brain systems over millions of years of biological and cultural evolution. Along the way, it latched onto disgust as a useful tool...The experimental data point to the possibility that our disgust system might have been adapted by evolution to allow us to reject or disapprove of abstract concepts such as ideologies and political views that are deeply influenced by culture, as well social groups associated with 'disgusting' concepts...In making symbolic distinctions between us and them visceral, disgust could potentially foster greater cohesion within groups by bringing people together in defence against a common out-group...Disgust works for the group as it does for the individual — what is in the group is 'me' and what is not is 'not me'...Where core disgust is the guardian of the body, moral disgust acts as the guardian of social body — that's when disgust shows its ugliest side.

...disgust is an emotion we are stuck with. Heuser suggests that the challenge... is to make people more reflective about what they say and think. He cites the success that advocates of political correctness have had in lowering the prevalence of casually sexist and racist language. Moll suggests optimistically that cultivating cultural and personal values of tolerance and empathy could function as an antidote to the toxic effects of disgust...by thinking less with our guts, and more with our heads and hearts, we might be able push back the boundaries of our moral world.

As in this Figure, Beauty or beast: things that once disgusted can in new contexts be tolerated.