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The Ghost World of Liberals and Conservatives
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October 2007
A Reproductive Advantage for Inconsistent Heterosexuality?
Sexual preference on a scale of 1-10, with 1 being the highest rating of homosexuality and 10 being the highest heterosexual rating
(Red=Female, Blue=Male)Natural selection is agnostic to sexual preference, and if a life mixed with both homosexuality and heterosexuality could yield more offspring than pure heterosexuality, then it would tend to be favored by evolution.
But this raises the question: how reproductive are those that are less than a purely heterosexual? How have they been competing with the pure heterosexuals when it comes to reproduction?
Our results have surprised even us, and may be evidence that inconsistent heterosexuality actually yields more offspring than pure heterosexual behavior.
In our Sex Survey, less than half of all males (46.0%) and a quarter of all females (26.6%) gave themselves a "10" on our sexual preference scale. This was the highest rating of heterosexuality that one could assign to themselves. Note that our survey consisted of 1,704 respondents, with 443 of those being females.
Our survey was heavily laden with Liberals, which are more likely to report lower rates of heterosexuality than Conservatives. But even given that, only 70% of the male Conservatives gave themselves a "10", while the other 30% believed their own heterosexuality was less than "pure".
As we shall see later, a significant number of those reporting high levels of heterosexuality have nonetheless had at least one homosexual experience.
What is going on with human sexual preference? While most genetic and biological studies focus on what is believed to be a homosexual community of between 5-10% of the population, they've yet to address the "incompleteness" of heterosexuality reported by most of the population--as evident in the above graph.
It appears that the human genome is not doing a very good job of producing pure heterosexuality, and most likely, it isn't trying to.
In fact, pure heterosexuality appears to be the exception, especially for females. The famed sex-researcher Alfred Kinsey proposed that homosexuality and heterosexuality were best described by a continuum of sexual preference, that is, most people were not purely homosexual or heterosexual, but fell somewhere in between.
Reproduction and Inconsistent Heterosexuality
The table below displays, by level of heterosexuality, the average number of children, the average number of children that one wants or wanted, and the percent that claim they never had a homosexual experience (to the point of orgasm).
Reproductive Effectiveness by Sexual Preference
Due primarily to the highly educated demographic of our survey respondents, the reproductive rates in the above table are lower than the population averages. However, they still indicate that those with lower ratings of heterosexuality, bisexuality, and homosexuality are still reproductive.
In general, the less heterosexual one is, the less children one wants and the less children one has. Predominately homosexual males wanted the fewest children (1.13) and also had the fewest children (0.33) of any cohort, while purely heterosexual males wanted the most (2.28) and had the most (1.18).
The bisexual males, on average, wanted 1.98 children, and had 0.89 children--not too far off the rate of the purely heterosexual males. The predominately heterosexual males wanted slightly less children than the purely heterosexual males (2.04), but had fewer children than the bisexual males (0.73).
On the female side, the pure heterosexuals wanted (2.10) and had the most children (1.12) , mirroring their male counterparts. The homosexual females still wanted children at a pretty high rate (1.41), and had 0.42 children.
It appears that female homosexuals are better at limiting the reproductive devastation of homosexuality than are their male counterparts, as seen in their higher rates of never having had a homosexual experience.
In our survey, the bisexual females wanted fewer children (1.43) than any of the female cohorts, and had the same as the predominately homosexual females (0.42). Note that 31.3% of females reporting they were bisexual had also reported that they have had no homosexual experience--something we'll discuss shortly.
The predominately heterosexual females looked very much like their male counterparts, wanting 1.96 children and having 0.73 children.
Repression of Homosexuality and Reproductive Rates
Now let's take a look at the curious relationship between homosexual experiences, heterosexuality, and reproduction.
Reproductive Effectiveness by Repression of Homosexual Tendencies
Had at least
one homo-
sexual
experienceAverage Num of Different
Sex
PartnersFemale Predominately Heterosexual Female The above table will require some explanation. Let's first focus on the predominately homosexual females.
Predominately Homosexual Females
Those females indicating that they are predominately homosexual yet never having a homosexual experience to the point of orgasm, were more reproductive than those that did have a homosexual experience.
On average, they wanted 2.4 children, and had 1.0 children--a surprisingly high reproductive yield for such a low level of heterosexuality.
Even more surprising is that their average age was 25, almost 7 years younger than the predominately homosexual females that had at least one homosexual experience. They also had very few sex partners (2.4), which in this case means few male partners. They also reported higher levels of monogamy when compared to the average female.
Now let's look at the predominately homosexual females that had at least one homosexual experience. They have fewer children (0.23), want fewer children, (1.09), and had many more sex partners (15.5).
Among the predominately homosexual females, the repression of homosexual tendencies is highly correlated with increased reproductive yield, as would be expected.
Predominately Homosexual Males
Now let's take a look at their male counterparts--the predominately homosexual males. Here we have the same result--the predominately homosexual males that have repressed their homosexual impulses, that is, have not had a homosexual experience, have a much higher reproductive yield (1.00 children) and also want more children (1.86) than those that have had a homosexual experience (0.22 and 1.02, respectively).
But puzzling is the very high number of sex partners that the predominately homosexual males with no homosexual experience report (19.6). Since this is a very small number in our sample (N=9), it appears to be due to one of those males indicating that they have had over 100 partners.
Since the rest of this respondent's answers passed our internal validity checks, we must include him in our results. However, removing his result lowers the average by about 10, not out of line with what we saw with their female counterparts.
The predominately homosexual males that have had at least one gay experience reported the most sex partners at 33.6.
A Reproductive Advantage for Inconsistent Heterosexuality?
In both genders, for those rating their sexual preference as bisexual, predominately heterosexual, and purely heterosexual, those having at least one homosexual experience have more children than those having had no homosexual experience.
Among those females indicating their sexual preference is bisexual, those having had at least one homosexual experience had 0.50 children while those having had no homosexual experience had 0.25.
This pattern is replicated to a lesser extent with the males indicating a sexual preference of bisexual, with those having a gay experience narrowly edging out those that did not, 0.93 to 0.79.
Among the predominately heterosexual females, those having a homosexual experience had 0.96 children, and those that did not had 0.66.
This pattern is repeated among the predominately heterosexual males, as those having a homosexual experience had 1.13, while those not having one had 0.61.
The purely heterosexual are interesting in that a surprisingly high number have had at least one homosexual experience (10.2% of females and 8.1% of males). This certainly questions the validity of their self-assessment of pure heterosexuality. But the reproductive yields of those having at least one homosexual experience were higher than those with none. (2.42 to 0.97 for females, 1.55 to 1.15 for males).
How Could This Be?
It is easy to see why suppression of homosexual behavior among those that are predominately homosexual would yield more offspring, as our results show. But explaining why those with higher self-ratings of heterosexuality seem to improve their reproductive yield when they mix in at least one homosexual experience is a bit more complicated.
In next month's edition, we will elaborate on this interesting phenomenon, as it seems that human sexuality, while under the influence of many disparate non-genetic factors, also seems to be under the substantial influence of many different genes, several of which seem to have slipped off of the X chromosome, and moved over to one of the autosomes.
To be continued...
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Don't stand so close to me
Conservatives, Liberals, and Peripersonal Space
Do people with high dominance status require more personal space?While personal space is that space reserved by the body, peripersonal space refers to the space surrounding our body, but still within reach of one of our limbs. This has a special neurological significance, as there are neurons that are sensitive to the space that is external to the body, but still within someone's grasp. So what has this got to do with politics?
We asked the 1,704 respondents to our Sex Survey, when you are around a stranger, how far away do you feel comfortable to stand? While this does not directly deal with the phenomenon of peripersonal space, we did get a rather interesting mix of results, as displayed in the graph below.
.
Distance (in feet) that one feels comfortable when standing next to a stranger
(F=Female, M-Male) (VL=Very Liberal, L=Liberal, M=Moderate, LB=Libertarian, C=Conservative, VC=Very Conservative)This above graph has a very pronounced trend among females, with the preferred distance becoming greater as one moves from left to right on the political scale. The Very Liberal females reported the shortest distance, 2.39 feet, while the Very Conservative females reported the largest distance, 3.15. Keep in mind that since this data came from our Sex Survey, we had very few Conservative and Very Conservative females (N=39).
The male pattern was less obvious, with a slight elevation among Conservatives. Both the Very Liberal and Liberal males reported 2.70 feet, while the Conservative and Very Conservative males reported 2.88 and 2.75 feet, respectively--not much of a difference.
The female pattern is certainly suspicious, and may hint at the various reproductive strategies among the political cohorts. However, from our survey, one of the highest correlations with "comfortable" distance from a stranger was with shyness.
But let's look at another interesting other phenomenon that also correlated with comfortable distance--number of sex partners, as seen in the graph below.
Distance (in feet) that one feels comfortable when standing next to a stranger (by number of sex partners and gender)
(F=Female, M-Male)The above graph depicts a close inverse correlation between numbers of sex partners and "comfortable" distance from strangers, in both genders. This correlation holds, though not as strongly, when controlling for shyness--therefore shyness does not explain why people that have a lot of sex partners also feel more comfortable standing closer to strangers.
Those with no (0) sex partners had the highest requirement for space, followed by those with 1-4 partners. In both genders, the space required declines as the number of sex partners goes up.
So what can we surmise from all this? Not too much, but it might indicate that serotonergic system "tone" might be related to both "comfortable" distance from strangers and number of sex partners. The stronger the serotonergic "tone", the more likely one will have more sex partners. It also tends to reduce spatial requirements, and may have an impact on the tendency to seek genetic variation in reproduction.
Something to note, since the Conservative females, the most restrictive genetically in reproduction, also require the most personal space when addressing strangers.
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Charles Brack and Xi Zhang, October 2007
Email: Brack@neuropolitics.org
Zhang@neuropolitics.org
The Amodio Experiment
Evidence of Hemispheric Lateralization in Conservatives and Liberals?
Aside from the obvious political implications of this experiment, there is a also a subtext of originality of concept, and how ideas that originate in the free-wheeling world of the web find their way into the insular and competitive world of scientific publishing--subsequently losing their proletarian bloodline.
The Amodio Experiment, entitled Neurocognitive correlates of liberalism and conservatism, is nonetheless a very important experiment in the short history of neuropolitics, and the first experiment that follows our basic theme of neurological variations in behavioral inhibition and reward seeking in conservatives and liberals. Further, it is a direct test of our proposal of asymmetric hemispheric lateralization in conservatives and liberals.
But it certainly isn't the first experiment to suggest that conservatives and liberals may be using their brains asymmetrically. One of the earliest pieces of evidence for our Conservative Left Brain, Liberal Right Brain hypothesis comes from Michael Gazzaniga's account of a split-brain patient named Paul. Paul had an unusually pronounced ability for language comprehension in his right hemisphere, which was unusual for a patient with a commissurotomy.
Patients with a severed corpus callosum behaved as if they had two distinct minds, often displaying conflicts between the left and right hands while performing simple tasks (see the last part of this Youtube video). When the corpus callosum is intact, these conflicts in motor control are resolved inside the brain, which ties in with the Amodio experiment.
Fortuitously, the social turmoil of the Watergate scandal was so great that it found its way into split-brain research, at which point Paul was queried about his opinions of Richard Nixon--once for each cerebral hemisphere.
Paul's left hemisphere expressed "like" for Richard Nixon, while Paul's right hemisphere expressed "dislike". Was Paul an isolated case, or did Gazzaniga and company stumble upon the greatest discovery in the history of political psychology?
This result, even if it could be replicated in other split-brain patients, would still not be sufficient to support the hemisphericity theory of political orientation, as it would also be consistent with a general aversion of the right hemisphere to people in powerful social positions, which indeed has some evidence to support it.
Unfortunately, the political and religious ramifications of this potential discovery were never followed up--only to become an interesting footnote in the history of split-brain research. But the diverse cognitive styles of the left and right hemispheres were certainly well correlated with the diverse cognitive styles of conservatives and liberals.
While Theodor Adorno (1950) is generally credited with linking cognitive unambiguity to right-wing political dispositions, he was actually preceded by another German (and Nazi) psychologist--Erik Jaensch (1938). Jaensch proposed that perceptual approaches formed a basis of personality, and proceeded to define the ideal Nazi personality as "strong" and "unambiguous", while "unstable" (i.e. "ambiguous") perceptual styles were labeled as "liberal".
Cognitive unambiguity is a distinct characteristic of the left brain--at least when it can be isolated from the right brain. While the cognitive evidence implicates that conservatives and liberals, on average, are not symmetric in how much their left and right hemispheres contribute to their overall behavior, the results from the recent Amodio Experiment may also be evidence for this theory.
But before Amodio, there were a handful of neuropolitical experiments with aspects that can also be interpreted to support hemisphericity in political and religious orientation, and we will briefly review a few of these.
The May and Masters Experiment
In Political Attitudes: Interactions of Cognition and Affect, Baldwin May and Roger Masters (1996) reported an interesting experiment that had Democrats and Republicans view videotaped excerpts of Bill Clinton "paired with preattentive anxiety-arousing images". Surprisingly to the authors, this had the curious impact of improving the Republican post-test evaluation of Clinton. Oddly enough, the post-test evaluations of the Democrats were virtually unchanged.
In other words, the elicitation of anxious mood states among the Republicans actually improved their opinions of Bill Clinton. When May and Masters could not reconcile this result with any existing psychological school of thought, they adopted the "rally-round-the-flag" effect--when in times of national stress, political support increases for the president. However, we'd like to suggest an alternate interpretation for this result. As we have previously noted, liberals are more likely to report anxious and depressive disorders than conservatives.
The elicitation of "anxious arousal" is primarily a right-lateralized cerebral function, as the right hemisphere is more specialized for monitoring threats, orienting towards potential threat, visuospatial attention, and exerting control over the autonomic and somatic functions in responding to threat--see Hager (1998), Sturm (1999), and Nitschke(1999, 2000).
Given the recruitment of additional right hemispheric resources during anxious arousal, it is certainly not out of line to suggest that this could be behind the unusual and unexpected "liberalizing" result, where stress seems to have induced Republicans to improve their opinion of Clinton.
The Grafman Experiment
An intriguing experiment by Kristine Knutson, Jacqueline Wood, Maria Spampinato, and Jordan Grafman, as described in Politics on the Brain: an fMRI Investigation, has several interpretations that relate to our hemisphericity theory.
Grafman et al. used a modified version of the Implicit Association Test, which matched 36 photos of well-known Republicans and Democrats with pleasant and unpleasant words, and then performed fMRI while the subjects handled congruent and incongruent words combined with the pictures of the Republicans and Democrats.
Note that the Grafman experiment had an unequal number of Democrats (n=15) and Republicans (n=9), nor does Grafman report these numbers by gender, which we believe may be a problem, since the cognitive evidence implicates that males and females are not politically or religiously equivalent, on average.
Further, Grafman does not break down the fMRI results by liberal and conservative, rather, lumps them together as if they were equivalent neurologically. Despite these deficiencies, Grafman had some pretty spectacular results.
First, Grafman implicated that activity in the left amygdala was correlated with the degree of affiliation towards one's political party and valence of one's beliefs. Grafman also identified activity in the left and right fusiform gyri (in the left and right temporal cortices, respectively) as being also being correlated with valence of beliefs and strength of political party affiliation. Grafman also noted a decline in lateral prefrontal activity associated with greater affiliation towards one's own political party.
We have previously noted, in The Impact of Introversion and Extroversion on Political and Religious Preferences, that conservatives were more likely to support their party's platforms than liberals. Since the activations of the left and right fusiform gyri in this experiment are probably due more to their specialized role in facial recognition, the activation of the left amygdala is of particular significance, due to its placement within the left medial temporal lobe.
Other research by Goel and Dolan support the notion that a left temporal system supports the phenomenon of belief bias, which could be overridden by the activation of the right lateral prefrontal cortex. The left temporal cortex is also suspected in elevated levels of religiosity, a common characteristic of conservatives.
However, to make sure that "logic" doesn't get in the way of human self-interest, Goel and Dolan found that the ventral medial prefrontal cortex (VMPFC) can overcome logical reasoning by interfering with the more "logical" regions of the prefrontal cortex. "Logic" in this case simply means that lower emotional valence is associated with the reasoning outcome. Evolution has done its best to interfere with cognitive states that interfere with self-interest.
And not so coincidentally, Grafman also proposed that the VMPFC was part of the emotional network associated with political attitudes, while the lateral prefrontal regions just happen to be part of Grafman's reasoning network--analogous to the findings of Goel and Dolan.
But equally fascinating was the assessment of "pecking order", where the subjects rated the relative ranking of the politicians within their own political party, from "most powerful" member to "minor role". Remarkably, pecking order was positively correlated with activity in the left cingulate gyrus and left medial frontal gyrus and negatively with the right cingulate gyrus and right medial frontal gyrus.
This fantastic result implies that the brain's rendering of dominance hierarchies are by inverse modulation by homologous regions of the left and right hemispheres. Given the left hemisphere's propensity for categorization in general, it may be carrying most, if not all, of the burden of hierarchical dominance categorization, while the right hemisphere is managing behavioral inhibition and aversion in proportion to that level of dominance.
In A Place in the Sun: Liberals, Conservatives, and Dominance Hierarchies, we speculated that the brain mapped an innate hierarchical dominance categorization schema within the left hemisphere, modeled on the reward categorization networks for such things as food types. This proposal is looking more reasonable in light of the results from Grafman, although it remains to be seen.
But it is intriguing to speculate that this neurology may be behind the "right-brained" liberal's low social valuation of the rich and powerful, while the "left-brained" conservative maintains a much higher value. Again, Grafman et al. did not break out their results by conservative and liberal cohorts. But even given some significant issues, the Grafman experiment had some very remarkable results.
The Kaplan Experiment
The Kaplan experiment, entitled Us versus them: Political attitudes and party affiliation influence neural response to faces of presidential candidates, has inadvertently run into the same territory as the Amodio experiment.
Unlike the Grafman and Amodio experiments, no tasks were required from the subjects as they were scanned while viewing 75 photographs of equal mixes of George Bush, John Kerry, and Ralph Nader. As we shall see, this seems to have been a bit of a problem.
Jonas Kaplan, Joshua Freedman, and Marco Iacoboni detailed their fMRI results on 10 Republicans and 10 Democrats while viewing these photographs during the 2004 presidential campaign. Also, note that no control photographs of non-politicians were used during this experiment.
With regards to both the Amodio experiment and our hemisphericity theory, there are several interesting things to note. First, on the self-assessment of emotional responses to the respective candidates, the Democrats were significantly more "negative" about George Bush than the Republicans were about John Kerry.
While this was not surprising, the Democrats also reported a much higher level of "negativity" towards John Kerry than the Republicans reported towards George Bush. On average, the combined negativity scores of the Democrats towards John Kerry and George Bush were much higher than the combined negativity scores of the Republicans.
The hemisphericity implications of this result are obvious, as the right hemisphere has for some time been implicated as specialized for "negative" emotions, while the left hemisphere is specialized for "positive" emotions. See Heath Demaree et al. (2005) for a comprehensive discussion on this.
As is usually the case in these studies, the fMRI results were differenced, that is, activations were relative to activations based on some alternate state. In this experiment, the relevant alternate states were the observing of the Bush photos and the observing of the Kerry photos.
While predominately bilateral activations were reported across the Bush minus Kerry and Kerry minus Bush contrasts for a variety of neural regions, Kaplan singled out the dorsolateral prefrontal cortex (DLPFC) and anterior cingulate cortex (ACC) as being more active in viewing the opposing candidate, a finding that has implications with both the Grafman and Amodio experiments. The more negatively the subjects felt about the candidate, the greater the relative activation of the DLPFC.
One of Kaplan's interpretations was:
"activity in the DLPFC/ACC network varied with the emotional response of the subjects suggest that the pictures of the candidates were eliciting cognitive control mechanisms for the purposes of emotional self-regulation".
So the primary issue with the Kaplan experiment might have been the presence of unfamiliar observers, the scientists, and the emotional control that subjects maintain in their presence. Since the subjects were asked to perform no tasks for this experiment, they were better able to elicit more cognitive inhibition of their emotional states. Thus the curious adaptation of the DLPFC and ACC, noted by Kaplan, seems to indicate a high degree of self-regulatiion of an emotional response.
But where were the amygdalar activations that received so much fanfare in their press-release in 2004? Those were asymmetrically activated in liberals by watching commercials with images of nuclear war, yet the "face" portion of their experiment yielded no such results. This was in contrast to the Grafman experiment, which noted amygdalar activity and gave a special significance to the VMPFC, which also received no discussion in Kaplan.
The Kaplan experiment is probably a good lesson in the benefits of task-based experimentation for future research. While the absence of congruence with the Grafman experiment can most likely be blamed on their methodology, it inadvertently brought them to the gates of the Amodio experiment, and its star of stars--the anterior cingulate cortex (ACC).
The Amodio Experiment
The Kaplan experiment could have been interpreted along the same theme of asymmetric behavioral inhibition in conservatives and liberals as was the Amodio Experiment. However, no such discussion was entertained, either because Kaplan et al. didn't see the political and religious significance of behavioral inhibition, or there was not enough evidence to make that claim. (Note: in 2004, we had a brief exchange with one of the co-authors, Iacoboni, about how their research may be implicating different conservative and liberal approaches to behavioral inhibition).
Enter the Amodio Experiment, and the hypothesis revealed by its authors, David Amodio, John Jost, Sarah Master, and Cindy Yee:
"we hypothesized that political orientation may be associated with individual differences in a basic neurocognitive mechanism involved broadly in self-regulation."
While new to the world of scientific publishing, this was hardly a new hypothesis in the wild world of the web. Variations in conservative and liberal behavioral inhibition mechanisms have been an obsession to us, as we discuss it in eleven different articles on this web-site, starting in January 2006, with Empathetic Neural Networks That Moderate Goal-Seeking in Conservatives and Liberals. (See also July 2006: Conservatives, Liberals, and Behavioral Inhibition: A tale of two moralities).
But what was original was Amodio's much more specific hypothesis:
"We proposed that differences in conservatives' and liberals' responsiveness to complex and potentially conflicting information relates to the sensitivity of this general mechanism for monitoring response conflict."
This is a very big statement. Amodio's "general mechanism for monitoring response conflict" was detailed in the sentences leading up to this hypothesis, and centered on Amodio's discussion of the anterior cingulate cortex (ACC):
"Conflict monitoring is a general mechanism for detecting when one's habitual response tendency is mismatched with responses required by the current situation, and this function has been associated with the neurocognitive activity in the anterior cingulate cortex."
Amodio's definition of conflict monitoring was certainly more restrictive than other authors, (e.g. Botvinick, Cohen, and Carter, 2004), that also include "tasks that required selection among a set of equally permissable responses". But it certainly tied in well with their experiment.
While Amodio et al. seem to be setting up an "anterior cingulate cortical" theory of political orientation, as they discuss the activation of no other brain regions in their paper--they back off this hard-line approach towards the end of their narrative:
"Taken together, our results are consistent with the view that political orientation, in part, reflects individual differences in the functioning of a general mechanism related to cognitive control and self-regulation".
So how did Amodio et al. come to this conclusion? Since Amodio's paper was only a two-page "Brief Communication" in Nature Neuroscience, the experimental details are a bit sketchy. They identify 63% of their 43 right-handed subjects as being female, but do not break down this ratio by political affiliation, so we do not know if the liberals were more heavily weighted with females, possibly influencing the results.
They also do not verbally state the numbers of conservatives and liberals used in their study, which we can only estimate from a plot they define as Figure 1-a. Based on this, we only count 8 people that would fall into the category of "conservative", that is, with a self-assessed score between 1 and 5 on their -5 to +5 single item scale, where -5 was extremely liberal, and +5 was extremely conservative.
Note also that their sample was shifted towards the "liberal" side of the political spectrum. Also, no mention of age or educational background was discussed, and hopefully these will be elucidated when they publish a more descriptive paper.
But in spite of these issues, the Amodio experiment seems to have hit paydirt. The experiment's computer-based task had the subjects view an "M" and a "W", with the "M" displayed 80% of the time, so as to induce a strong prepotent tendency to select it. (Note that they also performed this with the "W" displayed 80% of the time).
The "M" or "W" was displayed for only one-tenth of a second, at which point the subjects had only one-half second to respond with a "Go" or "NoGo" response on the computer keyboard, although they do not describe exactly what keys and which hands were employed in this task. If they did not respond in the half-second, a warning message appeared, and if they answered incorrectly, they were given feedback that their response was "incorrect".
Amodio el al. collected EEG readings from 29 scalp sites, distributed across "midline, frontal, parietal, temporal, and occipital locations" for the duration of the 15-minute, 500-trial test. From the readings, Amodio et al. computed error-related negativity, ERN, which is an electro-physiological marker believed to reflect activity in dopamine neurons as they respond to errors in cognitive tasks. If the subject entered "Go" when they should have entered "NoGo", this event was considered to be an ERN event.
The liberals, on average, displayed a significant elevation in ERN when compared to conservatives. Further, this elevation correlated with the strength of self-assessed liberalism, quite a remarkable result.
For the successful inhibition of a "Go" response (N2), that is, entering "NoGo" when seeing a "W" in the case of the 80% "M" prepotent condition, Amodio also found liberalism was related with "significantly greater conflict-related neural activity when response inhibition was required". Further, Amodio localized the ERN and N2 activity to the dorsal anterior cingulate cortex. This was another remarkable result, and given the design of their experiment, was probably what they were looking for.
The ACC and Behavioral Inhibition
The Grafman experiment reported on general activations of the cingulate gyrus, while Kaplan reported activations specifically on the anterior portion--the ACC. Both these studies reported numerous activations from a wide neural network, while Amodio only reported the ACC. We must add that both Grafman and Kaplan were fMRI studies, while Amodio was EEG.
The task associated with Amodio's experiment was more rigorous and required faster reaction time, and as a result, could be interpreted as activating a smaller neural network to handle the relatively simple yet rapid task of determining whether an "M" or "W" was displayed, and issuing a motor command to one of the fingers to respond to it.
The ACC has a suspiciously strategic location within the brain, right in the middle, wrapping around the major inter-hemispheric relay between the left and right cerebral hemispheres, the corpus callosum.
The ACC is also located adjacent to the prefrontal and premotor cortical regions, acting sort of like a computer "bus", to both speed up reaction time to novel stimuli and to select a single behavioral response when presented with multiple biased alternatives coming from other regions of the brain.
The connection between the Amodio experiment and our hemisphericity theory of political orientation lies in the laterality of the respective contributions of the left and right ACC in response selection during the display of the "W" in the 80% "M" condition (and vice-versa).
Based on our hemisphericity theory, the right ACC should be more involved in the decision to inhibit the prepotent condition and instead promote the selection of the correct response, which was the "W" in the case of the prepotent "M" conditioning.
The brain is a paired organ, and behavioral inhibition and behavioral activation have been proposed to be distributed asymmetrically among the right and left hemispheres, respectively. (see Heath Demaree et al. 2005). There is growing evidence that the right and left ACC are also asymmetric in functionality, falling along the same general theme as the right and left hemispheres.
This asymmetry of ACC functioning had been noted in Braver, Barch, Gray, Molfese, and Snyder (2001): "we also noted a small region of activity within the right ACC showing preferential activation during response inhibition". They further noted: "the test for regions selective to response inhibition (i.e. No-go responses) identified an almost wholly right-lateralized network".
This was also noted more recently by Lutcke and Frahm (2007):: "Multisubject analysis suggested a bilateral distribution of error-related processes in ACC, whereas correct inhibitions only seemed to activate ACC in the right hemisphere". Note that both Braver et al. and Lutcke and Frahm were fMRI experiments. Even the Grafman experiment alludes to the asymmetric activation of the right cingulate gyrus in the "faces incongruent" condition.
While it appears that the evidence is mounting for an asymmetric contribution of the right ACC to response inhibition, what did Amodio et al. have to say about it? Interestingly, laterality of activation of the ACC is not mentioned in the Amodio paper, possibly due to the lower resolution properties of EEG and the fact that the left and right ACCs are anatomically very close to each other. In fact, Amodio doesn't even mention the activation as being bilateral, although it is implied.
We queried David Amodio about whether he detected an asymmetry of ACC activity, and he replied: "I didn't notice an asymmetry in the No-Go N2 and ERN waves, though I hadn't explicitly looked for it".
Perhaps this will be elucidated in their formal paper, but even a bilateral activation of ACC functioning could be still interpreted as favoring the right ACC in contributing more to response inhibition, among other functions. However, spatial resolution of EEG is not as good as fMRI, and any possible inconsistency found with Amodio will certainly require some sort of explanation.
Hemisphericity and the ACC
The fact that Amodio et al. only mention the ACC has more to do with the design of their experiment, which seems to have promoted a more localized neural activation than either the Grafman or Kaplan experiments. Still, we cannot discount the fact that the lower resolution properties of EEG relative to the fMRI used in Grafman or Kaplan may also have something to do with it.
Obviously, a theory of political-religious affiliation based on a single neural region, such as the ACC, will not be a completely successful predictor for the politics of any one person. This is seen in Amodio's data, where, based on our count from a plot of ERN amplitude, Figure 1-a, the top scoring conservative beat 17 of the liberals.
In our cognitive surveys, we find this similar trend, where about 15-20% of conservatives and liberals fall solidly near the median laterality scores of the opposite political cohort. As we have previously noted, the greater the influence of the prefrontal cortex in one's aggregate behavior, the more "complex" one's political-religious behavior becomes. This is seen in the libertarians, which maintain a mixture of conservative and liberal tendencies, such as the desire for limited government and a lower disposition towards religious beliefs. They also exhibit a stronger cognitive influence of their left prefrontal cortex--at least in our surveys.
The concept of hemisphericity has taken quite a beating from many neuroscientists since the Beaumont et al. critique in 1984. This is mainly due to the problem of defining and measuring hemisphericity. Also complicating these issues were concepts of cerebral dominance. Due to the asymmetric specialization of the left and right hemispheres, they seem to alternate control based on the situation at hand, and maintain a good deal of independence, as they are more closely connected within their own hemisphere than with the contralateral hemisphere.
Further, many tasks are achieved bilaterally, although the respective contributions of the left and right hemispheres to aggregate behavior and cognition are not identical, and in some cases contradictory. If you've had a chance to look at the last part of the Youtube video, you can see how a good deal of interhemispheric conflict can occur in performing simple tasks, and why a region that manages response conflict, like the ACC, is so essential.
It appears that hemisphericity is the brain's way of resolving the natural conflicts inherent in the specialization that maximizes the processing capabilities of both hemispheres. This is most likely achieved on many fronts, from the response conflict management functions of the ACC, to the varying degree of interhemispheric communication via its downstairs neighbor, the corpus callosum, to the distributed network of cortical and sub-cortical regions waiting to seize control over the entire central nervous system given the right stimuli.
In short, hemisphericity is an immensely complex phenomenon, currently lending itself to neural models of insufficient complexity, yielding predictions that match observations with varying degrees of success. But the ACC and the corpus callosum are a good place to start, and have already yielded some promising results, as is evident with response conflict.
The beauty of the Amodio experiment lies in its focus on behavioral inhibition. In our view, conservatives and liberals will only be revealed by the study of behavioral inhibition, reward seeking, reproduction, inclusive fitness, genetic distance, and population biology.
Because of the very slow pace of neuropolitical experimentation, we encourage all future neuroimaging experiments to add a few simple screening questions pertaining to political and religious orientation, to be turned over, along with the imaging data, to research institutions that can provide further politically-oriented analysis. This would speed up the political knowledge gap considerably. This is especially true of neuroeconomics experiments, which seem to be singling out the ACC in reward seeking. Who knows, maybe one day all neuroimaging experiments will have to control for political-religious disposition just like they do for age and gender.
Finally, we believe that the Amodio experiment is another piece of evidence that supports of our "hemisphericity" theory of political orientation, which we more appropriately defined as the asymmetric functioning of the dopaminergic, noradrenergic, and serotonergic systems. However, this is far from a final theory, as we believe our "hemisphericity" theory only predicts about 60-70% of the general political and religious tendencies of an average human, and overlaps with genetic theories, due to the probable impact of the inheritance of cerebral laterality.
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Charles Brack and Xi Zhang, October 2007
Email: Brack@neuropolitics.org
Zhang@neuropolitics.org
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