(Differences between conservative and liberal brain is currently up for deletion; archiving the article with my recent additions in case I want to try a merge.)
Several studies have sought to find differences between the structure or functions of people's brain who identify as conservatives and liberals.
Nature Neuroscience in 2007 reported a study[1] by scientists at New York University and UCLA that showed that political orientation is related to differences in how the brain processes information. According to UCLA neurologist Dr. Marco Iacoboni, the study showed "there are two cognitive styles -- a liberal style and a conservative style."[2] The article "Neurocognitive correlates of liberalism and conservatism"[1] published in Nature Neuroscience "found that greater liberalism was associated with stronger conflict-related anterior cingulate activity, suggesting greater neurocognitive sensitivity to cues for altering a habitual response pattern."[1]
According to a 2011 study[3] by cognitive neuroscientist Ryota Kanai's group[4] at University College London published in Current Biology, people with different political views have different brain structure.[5] The scientists performed MRI scans on 90 volunteer young adult people's brains.[6] According to ABC, "Scans revealed that the liberal students tended to have a larger region of the brain that processes conflicting information. That, say the authors, might make for tolerance to uncertainty in more liberal views. The conservatives tended to have a larger part of the brain that processes fear and identifies threats. They might be more inclined to integrate conservative views into their politics." The results of the study showed that conservatives had a larger amygdala,[7] a almond-shaped structure of brain that processing and memory of emotional reactions.[8] Liberals had increased grey matter in the anterior cingulate cortex,[7] a comma-shaped structure of the brain that plays a role in a wide variety of autonomic functions, such as regulating blood pressure and heart rate, as well as rational cognitive functions, such as reward anticipation, decision-making, empathy[9] and emotion.[10][11] As a result of these structural differences, liberals may be more efficient at managing conflicting information, while conservatives may be more efficient at recognizing threats.[6][12][13] However, the researchers concluded, "It's very unlikely that actual political orientation is directly encoded in these brain regions."[13] Goddiscussion.com pointed out that the study gives no explanation for socially liberal, fiscally conservative or apolitical people.[14]
In an earlier fMRI study published in Social Neuroscience, three different patterns of brain activation were found to correlate with individualism, conservatism, and radicalism.[15] In general, fMRI responses in several portions of the brain have been linked to viewing of the faces of well-known politicians.[16] However, others believe that determining political affiliation from fMRI data is overreaching.[17]
According to the ASA, IQ data from the "Add Health" survey averaged 106 for adolescents identifying as "very liberal", versus 95 for those calling themselves "very conservative".[18][19][20][21][22][23][24] An unrelated study in 2009 found that among students applying to U.S. universities, conservatism correlated negatively with SAT, Vocabulary, and Analogy test scores though there was a greater correlation with economic differences.[25]
In a survey of the perceived severity of moral transgressions, conservatives were more affected by the taste of a bitter drink than liberals.[26] "...taste perception significantly affected moral judgments, such that physical disgust (induced via a bitter taste) elicited feelings of moral disgust. Further, this effect was more pronounced in participants with politically conservative views".
A study by scientists at New York University and the University of California, Los Angeles found differences in how self-described liberal an conservative research participants responded to changes in patterns.[27][28] Participants were asked to tap a keyboard when the letter 'M' appeared on a computer monitor and to refrain from tapping when they saw a 'W.' The letter 'M' appeared four times more frequently than W, conditioning participants to press the keyboard on almost every trial. Liberal participants made fewer mistakes than conservatives when they saw the rare W, indicating to the researchers that these participants were better able to accept changes or conflicts in established patterns.
The participants were also wired to an electroencephalograph that recorded activity in their anterior cingulate cortex, the part of the brain that detects conflicts between a habitual tendency and a more appropriate response. Liberals were significantly more likely than conservatives to show activity in the brain circuits that deal with conflicts during the experiment, and this correlated with their greater accuracy in the test.