Visuospatial orientation and religious belief
Motor activity, visuospatial performance,
and political-religious disposition
by Charles Brack
How does using your hands influence political disposition?
Previously, we noted the possibility that the left and right brains, when separated from each other, express divergent political and religious orientations: the left brain being more conservative and religious, while the right brain is more liberal and spiritual or atheistic. Does this mean that within every one of us resides a conservative and liberal, with the dominant hemisphere deciding which of these orientations to express in social contexts?
Things are not quite so simple in the brain, and even if the two brains diverge politically and religiously, brain dominance is one of the more controversial topics in the field of neuropsychology. Further, the neural mechanisms that execute hemispheric dominance are still shrouded in mystery.
Is there really such a thing as brain dominance?
The existence of "left-brained" and "right-brained" types is one of the most popular and persistent theories of personality. The "left-brained" personality is detail oriented, neat, rigid, judgmental, unemotional, and does not like change. The "right-brained" personality is artistic, messy, flexible, emotional, non-judgmental, and focused on the big picture.
While the general public has embraced this perspective, the scientific community is much less enthusiastic. This skepticism is based mainly on the plethora of neuroimaging studies that indicate the simultaneous activation of both hemispheres duing a wide range of cognitive tasks.
The problem with this viewpoint is that mutual activation of the hemispheres does not mean mutual function. During cases of mutual activation, each hemisphere is contributing something different. As we shall shortly see, people do exhibit differences in left or right brain dominance in responding to certain categories of stimuli, even when the non-dominant hemisphere is better suited to perform the task.
But are there really left-brained and right-brained personality types? Do the two hemispheres have different political orientations, and does brain dominance play a major in selecting our political and religious beliefs?
Let's go back to the early days of Roger Sperry and the original split-brain experiments. How did a person with a split brain exhibit barely perceptible deficits in walking? Why didn't the left and right sides of the body try to walk off in different directions?
How does using one's hands influence political disposition?
Walking is more reliant on subcortical activity than are hand movements. Since cortical activity is more likely to express interhemispheric conflict, the right and left hands are more likely to conflict with each other if the two hemispheres are separated. Indeed, this hemispheric conflict is seen in patients with alien hand syndrome.
Because the hands closely express the asymmetric nature of the left and right hemispheres, could they have anything to do with political orientation? Let's look at an interesting experiment by Princeton's Daniel Oppenheimer and Thomas Trail. They had 112 people squeeze a hand-grip for five seconds with either the left or right hand.
Those squeezing with their left hands scored higher on the liberal scale, while those squeezing with their right scored higher on the conservative scale. The left hand is closely linked to motor control by the right hemisphere, and the right hand by the left hemisphere.
So how does using one's hands influence political orientation? The spillover of motor activity into politics is one of consequences of our highly integrated nervous system. In Oppenheimer's experiment, motor activity in controlling the arm, hands, and fingers may also be priming cortical networks associated with political disposition. Thus, gripping with the left hand seems to be priming right hemispheric cortical networks which we believe are more associated with liberalism, while using the right hand has the opposite effect. The implications here are enormous, as any asymmetric activation of the human brain can potentially have political side-effects.
Can brain dominance hinder cognitive performance?
Back to the issue of brain dominance, or metacontrol. Optimally, the hemisphere that is best suited for a particular task should be the same hemisphere that takes control. Unfortunately, the brain has a mind of its own, and this doesn't always happen. One hemisphere can seize control even though the other hemisphere is better able to perform the task.
Let's look at some examples of this interesting subterfuge of cognitive efficiency for the sake of dominance. When the different hemispheres process nonsense syllables, such as DAG, they have different characteristics of identifying which letter of the nonsense syllable is incorrect.
The left hemisphere is superior to the right hemisphere in resolving which letter is in error. However, when both hemispheres are flashed a nonsense syllable, control is turned over to the right hemisphere, and the error pattern of the bilateral trials match the error pattern of the right hemisphere trials. For some reason, the brain was handing over control to the right hemisphere, even when the left hemisphere was better suited for the task.
This same theme was replicated by using chimeric faces flashed to the left and right hemispheres by Urgesi et al. (2005). Urgesi noted that hemispheric dominance was not solely influenced by hemispheric specialization, but by a variety of factors, such as which hemisphere was activated first by the stimulus.
In split-brain patients, the modality of the response dictated which hemisphere was dominant. If the split-brain patient was asked to point to which side of the chimeric face it saw, it would select the half-face seen by the right hemisphere. If asked to describe it verbally, it selected the half-face seen by the left hemisphere (Sperry et al., 1972; Levy et al, 1976), reflecting the verbal nature of the left hemisphere and the visual orientation of the right.
Four factors in executing cerebral brain dominance
Hemispheric dominance has been demonstrated to vary based on four factors: one's innate cognitive disposition (genetically and environmentally determined); the modality of response; the nature of the task at hand; and, the elicitation of emotional states or states of arousal. But what does this have to do with conservatives and liberals?
Let's take a look at how emotion interrelates with hemispheric dominance. It was demonstrated (Asbjornsen et al., 1992) that the right ear advantage in dichotic listening is neutralized by anxious mood states. In other words, the right hemisphere performed better in verbal tasks when primed by an anxious emotional mood state of a moderate degree.
The elicitation of anxious-arousal is primarily a right-lateralized cerebral function (Nitsche, 1999), as the right hemisphere is more specialized for monitoring threats, visuospatial attention, and exerting control over the autonomic and somatic functions in responding to threat.
Interestingly, relative to conservatives, liberals report higher rates of anxious arousal, depression, bipolar disorder, agoraphobia, OCD, panic disorder, and social anxiety disorder.
The connection between anxiety, the right hemisphere, and liberal political attitudes, was noted in an experiment by Way and Masters (1996). They found that elicitation of anxious-arousal mood states in Republicans actually resulted in an improvement of their attitudes about the Democrat Bill Clinton.
While this is potential evidence that right hemisphere dominance contributes to liberal attitudes, there are other indicators that left hemispheric dominance plays a major role in conservative political attitudes.
Unambiguous left hemispheres make for unambiguous conservatives
One of the earliest proposals of the psychological differences between the right and left wing came from the Nazi psychologist Erich Jaensch in 1938.
Erich Jaensch and Else Frenkel-Brunswik
(Political opposites and founders of the psychological study of political disposition)
Jaensch proposed that liberals were susceptible to synesthesia, or the tendency for stimuli presented in one sensory domain to leak over into the other domains. For example, the word "cool" could evoke the color sensation of blue to a person with synesthesia. According to Jaensch, the liberals and Jews had this problem, and as a result, were perceptually unstable.
Ten years later, this perceptual dichotomy was again proposed by the leftist Else Frenkel-Brunswik. To Frenkel-Brunswik, conservatives had a tendency to perceive the world in binary terms, such as "good" and "evil", while the liberals were much more likely to think in terms of probabilities.
As such, cognitive ambiguity is one of the primary differences between conservative and liberal thinking styles, as illustrated by this:
Preference for unambiguity: percentage believing there is a right and wrong way to do everything
Is there a right and wrong way to do everything? Such an seemingly innocuous question exposes a very large difference in the cognitive traits of conservatives and liberals. As you can see, only about 10% of the very liberals believe there is a right and wrong way to do everything, while 62% of the very conservatives believe so. Even more interesting is that this pattern is virtually a linear function of political preference, with the moderates falling in between the liberals and conservatives.
Compared to liberals, conservatives are more likely to have a definite opinion on almost any subject. But what does this have to do with the left hemisphere? Let's look again at one of Michael Gazzaniga's split-brain patients.
Gazzaniga noted the strong tendency for the left hemisphere to establish causality. Gazzaniga refers to this as the left-hemisphere "intrepreter". Eugene d'Aquili proposed (1978) an analogous process, also in the left hemisphere, which he referred to as the "causal operator". Like Gazzaniga's interpreter, d'Aquili's causal operator strives to link events and generally reduce ambiguity, even if it is at the expense of reality (schizophrenics have a stronger tendency for ambiguity reduction).
Often wrong, but never in doubt
The reduction in ambiguity to a particular stimulus can have the substantial benefit of quicker behavioral reaction, and further, the reduction in mental resources associated with analysis and orientation. The quicker the stimulus is assigned some sort of behavioral saliance, be it to fight, flee, approach, or ignore, the more effective that behavior can be.
Therefore, ambiguity reduction is a key phase for behavioral planning, and subsequently, motor planning. This is consistent with the well-established hypothesis that the left-hemisphere is dominant for motor planning (e.g., Frey 2008; Haaland, 2000; Kim, 1993; Leiguarda, 2000). It could also be argued that motor planning is more efficient after the reduction of ambiguity.
The difficulties of the left hemisphere in processing semantic ambiguity is also consistent with its tendency to reduce ambiguity. Several studies have noted the recruitment of the right hemisphere in processing lexical ambiguity, non-literality, and the global dependence of word meanings (e.g. Titone, 2004; Chan, 2004; Mashal, 2008).
Good, evil, and the binary world of religious conservatives
But this tendency for literal interpretation and the tendency to view the world in terms of good and evil appear to both be linked to the left hemisphere. The left hemisphere, and in particular, the left inferior parietal lobe, is prone towards the categorization of semantic opposites, such as good and evil, up and down, left and right, and heaven and hell. Eugene D'Aquili (2001) referred to this as the "binary operator", or the propensity towards organizing stimuli into opposing categories.
The location of the "binary operator" is interesting, in that portions of the left parietal cortex have been implicated in the preparation for redirections of body movements (Rushworth, 2003). This propensity to categorize stimuli into opposites often occurs with the preference for one of those opposites, such as good over evil, beautiful over ugly, bravery over cowardice, etc.
Has the cognitive rendering of semantic opposites, such as good and evil, been built upon the neural management of redirecting body movements, which in turn may be linked to our fight or flight instinct?
The unambiguous and binary thinking styles of conservatives raises an interesting question about the correlation between political-religious disposition and overall cognitive performance. Do religious conservatives perform better at certain cognitive tasks than do secular liberals, and vice-versa?
The left and right parietal cortices inhibit each other with certain tasks
Doubting the existence of God
Let's look at the relationship between binary thinking and visuospatial task performance. Both of these cognitive propensities preferentially engage the left and right parietal cortices, respectively. Further, visuospatial task performance has been improved by rTMS stimulation to the left parietal cortex, implying the left parietal cortex inhibits the visuospatial performance of the right (and vice-versa) (Hilgetag, 2001).
In 2005, Neuropolitics.org noted a decline in visuospatial task performance in both males and females with a propensity for binary thinking styles. This decline in performance was particularly notable for both males and females that described themselves as very religious. In fact, very religious females performed only at chance with the visuospatial tasks attempted.
This could be interpreted as an inhibition of the right parietal cortex by the propensity for the very religious to preferentially engage their left parietal cortex.
Gray matter volume in the right parietal cortex is enhanced for those doubting the existence of God
Finally, this leads right into a anatomical finding of Grafman et al. (2009). Grafman noted a positive correlation between doubting the existence of God and gray matter volume of both the right precuneus (BA 7, part of the superior parietal cortex), and the right primary visual cortex (BA 17). This finding is consistent with the hypothesis that elevated levels of religiosity negatively impact certain aspects of visuospatial performance.
However, we suspect that this proposed deficit in visuospatial reasoning is compensated by enhancements in certain semantic and arithmetic specializations of the left hemisphere, implying that diversity of political-religious disposition in a population can improve the total cognitive capacity of that population. Of course, that presumes that conservatives and liberals still talk to each other.
Charles Brack, March 2012
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