While there are many reasons for the resilience of this myth, the most powerful one is the simple fact that humans today can and do engage in extreme levels of violence and aggression. If you read the newspaper, visit online news sites or turn on the television, you are guaranteed to come across some evidence of humans behaving violently toward other humans. While many animals aggressively hunt, capture, and eat prey, it is relatively rare for most animals to engage in intense, lethal aggression with members of their own species.

Many social mammals display some intraspecific (within the same species) aggression and violence, sometimes resulting in death. A male lion might seriously injure another male lion in a fight over access to a pride of females, two rams might butt heads until one of them staggers away seriously hurt, or a male baboon might repeatedly attack a female in his group, wounding her and injuring her infant. However, these events, while aggressive and violent, are not the main ways in which the individuals in these species interact. For the most part, death of opponents in these cases is neither the premeditated goal nor the outcome of the behavior. So, while intraspecific violence occurs, most species do not exhibit extreme aggression regularly and methodically. Humans are the only species that practice premeditated homicide and full-out war. That humans can, and do, participate in aggression and violence in ways that most other animals do not (and cannot) has led many to theorize that this aggression, this inner beast or demon, our Mr. Hyde, is part of human evolutionary heritage.

The myth of human aggression holds that we are indeed evolved to be killers, or at least aggressors who use the threat of violence as a major evolutionary tool. The mark of this evolved tendency toward aggression can therefore be found in our bodies and minds, especially those of men:

When we look at humans’ bodies and brains, we find more direct signs of design for aggression. The larger size, strength, and upper-body mass of men is a zoological giveaway of an evolutionary history of violent male-male competition. . . . (Stephen Pinker, psychologist)

There is the notion that aggression, the capacity for immense violence, evolved specifically because of the benefits it gave males, including an edge in competition with one another and between groups of males. Some make the argument for indicators of aggressive cores in our closest primate relatives and suggest that aggression and violence result in evolutionary benefits:

Thus, both the patterns of deadly violence in nature and the ethnographic record of simple hunter-gatherers clearly suggest that intraspecific human violence and the threat of it, while obviously undergoing transformations and varying in form through human history, are on the whole as old as humanity itself, indeed as old as nature. . . . (Azar Gat, political scientist)

In short, the myth of human aggression is that humans (especially males) have a specific and distinct tendency toward aggression and violence and that this is patterned in our bodies and minds and arose due to evolutionary pressures of competition between men and between groups. If this were true, then aggression and violence must be a core part of who we are as humans because over evolutionary time those with the more aggressive behavioral patterns or traits must have defeated opponents and mated more successfully than those who were more pacific.

It is obvious that human aggression is an amazingly complicated thing. There is variation in conflict styles and aggression across individuals, sexes, genders, societies, and time frames. Aggression is an important part of being human, but it is not who we are at our core. We now know that aggression itself is not a uniform or consistent discrete trait, so aggression per se cannot be favored by evolutionary pressures to form the basis of the human experience.

The other primates show us that we do not have specific, evolved patterns of heightened aggression, especially in males. Looking at the chimpanzee species demonstrates the potential for variability in the expression of aggressive and nonaggressive behaviors in our shared ancestors. War is common in the human experience today, but it is not a central part of our evolutionary heritage. We know that males and females differ in some facets of aggression, but a lot of those differences have to do with physical size and the social and experiential contexts in which they find themselves. We know that more aggressive, more violent, or more warlike males do not necessarily do better, either in humans or in our closest relatives.

Human aggression, especially in males, is not an evolutionary adaptation: we are not aggressive, big-brained apes. We know the regions of the brain and body that influence normal aggression. While our genes do not control or determine the normative expression of aggression, abnormal biological function can influence particular patterns of aggressive behavior. The nature of human aggression is not found in our genes, but understanding the function and variation in our biology can help us better understand the pathways and patterns of aggressive behavior. As a species we do not rely on aggression and violence more than cooperation; there is no pattern of evidence to support a notion that humanity is aggressive and selfish by nature. The myth of a human nature characterized by an intrinsic aggressiveness is simply not true.

And yet the popular press and much of the public (and some academics) hold the belief that there is a specific biology or a genetic basis for aggression, especially in males. Identifying the genetic key to aggression is not possible, because it does not exist.

It is pretty clear that in humans two parts of the brain, called the prefrontal cortex and the dorsal anterior cingulated cortex, are centrally involved with the expression of behavior, especially aggression. The prefrontal cortex is linked to other behaviorally important brain structures called the amygdala and the hypothalamus. In general, these parts of the brain receive a variety of inputs from other areas of the brain (vision, smell, touch, pain, sound, memory, language, etc.) and then interact in a sort of feedback loop to stimulate other bodily systems (such as hormones, neurotransmitters, and muscles) into action.

The prefrontal cortex does a bunch of other things as well, including playing central roles in introspection, recognition of emotions, regulation of emotions, and detection of conflict situations, and it acts as a trigger to initiate a variety of other neurological systems in regard to social interactions. The dorsal anterior cingulated cortex seems to be involved in the regulation of responses to anger, pain, and social rejection. From brain imaging studies, we know that individuals who are particularly aggressive often show lowered neuronal activity, reduced glucose metabolism, or even reduced density of gray matter in the prefrontal cortex than those who are not as aggressive. Studies of individuals who have received brain damage to the prefrontal cortex and amygdala reveal that they demonstrate more impulsive and antisocial aggressive behavior or have lowered abilities to control the expression of aggression.

Additionally, shock therapy in the 1950s and 1960s directed at the amygdala and prefrontal cortex resulted in lowered overall arousal rates and severely reduced aggression. In short, there are multiple studies which all point to the action of the prefrontal cortex, the dorsal anterior cingulated cortex, and at least the amygdala, as important areas for understanding the biological infrastructure of aggression.

There are a suite of molecules (called neurotransmitters) produced by the body which directly interact with these regions of the brain and are involved in the expression of aggressive behavior (among other things). They are the 5-hydroxytryptamine receptors (5-HT for short and involved with the neurotransmitter serotonin), the neurotransmitter and neurohormone dopamine, the metabolic enzyme monoamine oxidase A (MAOA), and a variety of steroid hormones such as testosterone, other androgens, and estrogen. None of these are a smoking gun for the origin and expression of aggression in general, but some of these are implicated, to some extent, as playing a role in the emergence of particular types or patterns of aggression.

Genes are basically just stretches of DNA that contain the code for either the production of a protein molecule (or parts of a molecule) or the regulation of other genes or of themselves. Genes come in multiple forms (alleles). While genes contain codes for proteins and their regulation, the relationship between genes and complex molecules like neurotransmitters and hormones is very complicated.

Dubbed the “warrior gene” in the press, the gene that codes for monoamine oxidase A (MAOA) has recently been a central player in the study of genetic influences on aggressive behavior. This gene is found on the X chromosome (the one you get from your mother), so that males have only one copy of it and females have two (males are XY and females are XX). The gene product, the enzyme monoamine oxidase A, interacts with the neurotransmitters serotonin, dopamine, and norephedrine, regulating their release and breakdown so that once they do what they are supposed to do they don’t build up or interact with other receptors, causing problems for communication between parts of the brain.

It turns out that there are at least four different common alleles for this gene that have the effect of increasing or decreasing the amount of MAOA produced. Lowered amounts of MAOA in the brain in some mice, rhesus monkeys, and humans, under certain conditions, is associated with increased aggression and reduced ability to control impulsive behavior. A noticeable number of mice, monkeys, and human males who had the low-MAOA-production alleles and who experienced severe social and/or physical trauma or abuse during early childhood development were more likely to express heightened aggressive and antisocial behavior as adults. Some low-MAOA humans also score higher on self reports of aggressive and violent behavior. However, in some cases the high-producing alleles are correlated with aggressive behavior in male children. In a famous case of a Dutch family who have a very rare allele where no MAOA is produced at all, three males exhibited extreme aggressive and antisocial behavior. Now, not all individuals with the low-expression alleles exhibit this kind of aggression, not even all of those with the low-expression alleles who had traumatic or abusive childhoods. In addition some of the high-expression allele carriers exhibited high aggression.

All of these studies were conducted on males because it is much easier to discover which alleles are acting as the males only have one copy of the gene. In females it is more difficult to identify the actual action of the gene because they may have two copies but only one is actually active; determining which one that is can be very difficult. Thus, while this gene is often invoked as an example of a male biological basis of aggression, there have been no in-depth studies of this gene in females so we do not know if it functions the same way. We should note that the enzyme MAOA operates exactly the same in the females’ brains as it does in males.

This research focuses on the variation in allele frequencies for MAOA and the relationship that its expression has to early social and physiological experiences during development and its variation in functional outcomes in different social contexts. In other words, this is an underlying genetic element that plays an interesting role in affecting the brain structures that are associated with the expression of aggression. But the behavioral outcomes of gene variation are totally dependent on the patterns in early life experience and the social context in which some carriers of the low-production allele find themselves. The bottom line is that if you have a low-expression allele and you undergo severe childhood trauma or abuse, then the likelihood of your having problems in the neurological infrastructure of aggression that result in higher aggression is higher than if you had the regular-production allele.

Most people have heard of serotonin, but most do not know that it is tied to the neurotransmitter 5-hydroxytryptamine (5-HT for short). Of all the well-known neurotransmitters this is the one best recognized for affecting behavior, especially aggression. The main way in which 5-HT relates to aggression has been determined from studies of the variation in the receptors that interact with 5-HT. There are at least thirteen types of 5-HT receptors and multiple molecules that interact with, and regulate, 5-HT in the brain. In general, it appears that serotonin concentrations in the brain, and the way they interact with receptors, can modulate aggression and violent behavior in mammals, including humans (although the vast majority of the research has been done with rodents).

In general, low 5-HT levels are associated with higher levels of aggressive or impulsive behavior and high 5-HT levels and/or manipulation of the 5-HT receptors in different parts of the brain can act to reduce aggression. Genetic evidence for these impacts comes almost completely from studies of rodents: mice or rats missing specific genes that affect 5-HT concentrations or the production of 5-HT in certain brain regions are more aggressive. But this is not true for all 5-HT, as manipulation of certain receptors and of concentrations of 5-HT in different parts of the brain have different types of impacts on aggression, anxiety-related behavior, and impulsivity. In the few studies of humans that track 5-HT relating to aggression there is a negative relationship between the ability of 5-HT receptors to bind to neurotransmitters and aggression, which supports the notion that this molecule impacts the expression of aggressive behavior.

One of the most interesting findings from the 5-HT studies is that, in rodents, different types of 5-HT receptors have different impacts on expressed aggression, depending on whether the rodents were exhibiting “normal” territorial aggression or impulsive pathological aggression stimulated by drugs or electric shock. This suggests that the various genes that code for the different 5-HT types are involved in different systems in aggression and that they might in fact have multiple, even mutually negating, roles in the production and expression of aggressive behavior depending on the social context and the type of aggression expressed. So while 5-HT is definitely involved in the expression, and probably the modulation, of the level of aggression, there is no evidence that this is where aggression comes from.

There is ALSO a strong popular assumption that testosterone stimulates or enhances aggression, especially in males. First off, it is important to note that testosterone courses through both male and female bodies, but that on average, males have higher circulating levels than females. Testosterone is a steroid hormone closely related to estrogen and a suite of hormones called androgens. Little is known about the underlying genetic structures that influence testosterone, but there is no doubt that some genetic variation influences the production and regulation of testosterone in human bodies.

The concept that testosterone produced by males facilitates and increases aggression is an oversimplification and there are very weak or inconsistent correlations between testosterone levels and aggression in adult humans. Even when external sources of testosterone are administered to adults their aggression does not tend to increase, nor is there an increase in aggression at puberty when human males undergo a significant increase in the production of testosterone and the development of male secondary sexual characteristics.

There is evidence that in competitive or acute stress situations humans can respond by increasing the production of testosterone but there is no strong or consistent evidence that these increases result in increased aggressive behavior. The increase does appear to enhance muscle activity and efficiency and might also result in lower sensitivity to pain or punishment in both men and women. This might make individuals more likely to participate in aggressive competition, but it does not increase aggression per se. In some experiments the levels of circulating testosterone increase after dominance interactions and social competition, but again this is not necessarily tied to overly aggressive behavior. Exposure to sexual situations and to communal competitive events (like team sports) also appears to increase testosterone in males. Interestingly, males who are fathers and or long-term married partners show lower levels of testosterone than do nonfathers or unmarried males.

Overall, testosterone seems to be associated with the efficiency and activity of a variety of muscular and other physical systems, some of which are implicated in the expression of aggression. But contrary to popular misconceptions, testosterone itself is not associated in any causal way with increased aggressive behavior or in the patterns of the exhibition of aggression.

Despite popular notions that certain genes or genetic elements control or regulate the appearance and intensity of aggressive behaviors, there is no evidence for any one-to-one genetic controls, nor is there evidence for certain molecules or systems in the body that predetermine aggressive outcomes. There is no gene or system in the body that can be identified as “for aggression.” While it appears clear that genetic variation in neurotransmitters and hormones can be involved in the ways in which we express aggressive behavior, there is no direct or casual link. Our genes cannot make us aggressive.

As the anthropologist Ashley Montagu sagely cautioned, “It is essential that we not base our image of ourselves on false foundations. What is involved here is not simply the understanding of the nature of humanity, but also the image of humanity that grows out of that understanding.” Humans are not naturally aggressive, but they do have a great potential for aggression and violence. If we believe we are aggressive at our base, that males stripped of social constraints will resort to a brutish nature, then we will expect and accept certain types of violence as inevitable. This means that instead of really trying to understand and rectify the horrific and complex realities of rape, genocide, civil war, and torture, we will chalk at least a part of these events up to human nature. This is a dangerous state of mind that traps us in a vicious cycle of inaction and futility when it comes to moving forward as societies invested in understanding and managing violence.

Sure, certain things spur aggressive actions, but the common notions about our inner, natural aggressive tendencies (especially in males) ignores the complexity of human biology, psychology, history, and society. It downplays the myriad ways in which aggression is initiated and maintained, and oversimplifies what we can mean by, and understand about, human aggressive behavior. And, most dangerously, it enables a kind of inevitability in our communal sense of aggression and society, especially as it relates to males. This need not be the case.

As she read my mood with such fluency, I thought about the man who had been my coworker and partner in frustration that day—the physicist Stephen Hawking, who could hardly move a muscle, thanks to a forty-five-year struggle with motor neuron disease. By this stage in the progression of his illness, he could communicate only by painstakingly twitching the cheek muscle under his right eye. That twitch was detected by a sensor on his glasses and communicated to a computer in his wheelchair. In this manner, with the help of some special software, he managed to select letters and words from a screen, and eventually to type out what he wanted to express. On his “good” days, it was as if he were playing a video game where the prize was the ability to communicate a thought. On his “bad” days, it was as if he were blinking in Morse code but had to look up the dot and dash sequence between each letter. On the bad days—and this had been one of them—our work was frustrating for both of us.

And yet, even when he could not form words to express his ideas about the wave function of the universe, I had little trouble detecting when his attention shifted from the cosmos to thoughts of calling it quits and moving on to a nice curry dinner. I always knew when he was content, tired, excited, or displeased, just from a glance at his eyes. His personal assistant had this same ability. When I asked her about it, she described a catalog of expressions she’d learned to recognize over the years. My favorite was “the steely-faced glint of glee” he displayed when composing a potent rejoinder to someone with whom he strongly disagreed. Language is handy, but we humans have social and emotional connections that transcend words, and are communicated—and understood—without conscious thought.

The experience of feeling connected to others seems to start very early in life. Studies on infants show that even six-month-olds make judgments about what they observe of social behavior. In one such study infants watched as a “climber,” which was nothing more than a disk of wood with large eyes glued onto its circular “face,” started at the bottom of a hill and repeatedly tried but failed to make its way to the top. After a while, a “helper,” a triangle with similar eyes glued on, would sometimes approach from farther downhill and help the climber with an upward push. On other attempts, a square “hinderer” would approach from uphill and shove the circular disk back down.

The experimenters wanted to know if the infants, unaffected and uninvolved bystanders, would cop an attitude toward the hinderer square. How does a six-month-old show its disapproval of a wooden face? The same way six-year-olds (or sixty-year-olds) express social displeasure: by refusing to play with it. That is, when the experimenters gave the infants a chance to reach out and touch the figures, the infants showed a definite reluctance to reach for the hinderer square, as compared to the helper triangle.

Moreover, when the experiment was repeated with either a helper and a neutral bystander block or a hinderer and a neutral block, the infants preferred the friendly triangle to the neutral block, and the neutral block to the nasty square. Squirrels don’t set up foundations to cure rabies, and snakes don’t help strange snakes cross the road, but humans place a high value on kindness. Scientists have even found that parts of our brain linked to reward processing are engaged when we participate in acts of mutual cooperation, so being nice can be its own reward. Long before we can verbalize attraction or revulsion, we are attracted to the kind and repelled by the unkind.

One advantage of belonging to a cohesive society in which people help one another is that the group is often better equipped than an unconnected set of individuals to deal with threats from the outside. People intuitively realize that there is strength in numbers and take comfort in the company of others, especially in times of anxiety or need. Or, as Patrick Henry famously said, “United we stand, divided we fall.” (Ironically, Henry collapsed and fell into the arms of bystanders shortly after uttering the phrase.)

Consider a study performed in the 1950s. About thirty female students at the University of Minnesota, none of whom had previously met, were ushered into a room and asked not to speak to each other. In the room was a “gentleman of serious mien, horn-rimmed glasses, dressed in a white laboratory coat, stethoscope dribbling out of his pocket, behind him an array of formidable electrical junk.” Seeking to induce anxiety, he melodramatically introduced himself as “Dr. Gregor Zilstein of the Medical School’s Departments of Neurology and Psychiatry.” Actually, he was Stanley Schachter, a harmless professor of social psychology. Schachter told the students he had asked them there to serve as subjects in an experiment on the effects of electric shocks. He would be shocking them, he said, and studying their reactions. After going on for seven or eight minutes about the importance of the research, he concluded by saying,

“These shocks will hurt, they will be painful. . . . It is necessary that our shocks be intense. . . . [We will] hook you into apparatus such as this [motioning toward the scary equipment behind him], give you a series of shocks, and take various measures such as your pulse rate, blood pressure, and so on.”

Schachter then told the students that he needed them to leave the room for about ten minutes while he brought in still more equipment and set it all up. He noted that there were many rooms available, so they could wait either in a room by themselves or in one with other subjects. Later, Schachter repeated the scenario with a different group of about thirty students. But this time, he aimed to lull them into a state of relaxation. And so, instead of the scary part about intense shocks, he said, “What we will ask each of you to do is very simple. We would like to give each of you a series of very mild electric shocks. I assure you that what you feel will not in any way be painful. It will resemble more a tickle or a tingle than anything unpleasant.”

He then gave these students the same choice about waiting alone or with others. In reality, that choice was the climax of the experiment; there would be no electric shocks for either group.

The point of the ruse was to see if, because of their anxiety, the group expecting a painful shock would be more likely to seek the company of others than the group not expecting one. The result: about 63 percent of the students who were made anxious about the shocks wanted to wait with others, while only 33 percent of those expecting tickly, tingly shocks expressed that preference. The students had instinctively created their own support groups. It’s a natural instinct. A quick look at a web directory of support groups in Los Angeles, for example, turned up groups focused on abusive behavior, acne, Adderall addiction, addiction, ADHD, adoption, agoraphobia, alcoholism, albinism, Alzheimer’s, Ambien users, amputees, anemia, anger management, anorexia, anxiety, arthritis, Asperger’s syndrome, asthma, Ativan addiction, and autism — and that’s just the A’s. Joining support groups is a reflection of the human need to associate with others, of our fundamental desire for support, approval, and friendship. We are, above all, a social species.

Social connection is such a basic feature of human experience that when we are deprived of it, we suffer. Many languages have expressions—such as “hurt feelings”—that compare the pain of social rejection to the pain of physical injury. Those may be more than just metaphors. Brain-imaging studies show that there are two components to physical pain: an unpleasant emotional feeling and a feeling of sensory distress. Those two components of pain are associated with different structures in the brain. Scientists have discovered that social pain is also associated with a brain structure called the anterior cingulate cortex—the same structure involved in the emotional component of physical pain.

It’s fascinating that the pain of a stubbed toe and the sting of a snubbed advance share a space in your brain. The fact that they are roommates gave some scientists a seemingly wild idea: Could painkillers that reduce the brain’s response to physical brain also subdue social pain? To find out, researchers recruited twenty-five healthy subjects to take two tablets twice each day for three weeks. Half received extra-strength Tylenol (acetaminophen) tablets, the other half placebos. On the last day, the researchers invited the subjects, one by one, into the lab to play a computer-based virtual ball-tossing game. Each person was told they were playing with two other subjects located in another room, but in reality those roles were played by the computer, which interacted with the subjects in a carefully designed manner. In round 1, those reputedly human teammates played nicely with the subjects, but in round 2, after tossing the virtual ball to the subject a few times, the teammates started playing only with each other, rudely excluding the subject from the game, like soccer players who refuse to pass the ball to a peer. After the exercise, the subjects were asked to fill out a questionnaire designed to measure social distress. Compared to those who took the placebo, those who took the Tylenol reported a reduced level of hurt feelings.

There was also a twist. These researchers had the subjects play the virtual ball game while lying in an fMRI machine. So while they were being snubbed by their teammates, their brains were being scanned by the machine. It showed that the subjects who’d taken Tylenol had reduced activity in the brain areas associated with social exclusion. Tylenol, it seems, really does reduce the neural response to social rejection.

When the Bee Gees long ago sang “How Can You Mend a Broken Heart?” they probably didn’t foresee that the answer was to take two Tylenols. That Tylenol would help really does sound far-fetched, so the brain researchers also performed a clinical test to see if Tylenol had the same effect outside the lab, in the real world of social rejection. They asked five dozen volunteers to fill out a “hurt feelings” survey, a standard psychological tool, every day for three weeks. Again, half the volunteers took a dose of Tylenol twice a day, while the other half took a placebo. The result? The volunteers on Tylenol did indeed report significantly reduced social pain over that time period.

The connection between social pain and physical pain illustrates the links between our emotions and the physiological processes of the body. Social rejection doesn’t just cause emotional pain; it affects our physical being. In fact, social relationships are so important to humans that a lack of social connection constitutes a major risk factor for health, rivaling even the effects of cigarette smoking, high blood pressure, obesity, and lack of physical activity. In one study, researchers surveyed 4,775 adults in Alameda County, near San Francisco. The subjects completed a questionnaire asking about social ties such as marriage, contacts with extended family and friends, and group affiliation. Each individual’s answers were translated into a number on a “social network index,” with a high number meaning the person had many regular and close social contacts and a low number representing relative social isolation. The researchers then tracked the health of their subjects over the next nine years. Since the subjects had varying backgrounds, the scientists employed mathematical techniques to isolate the effects of social connectivity from risk factors such as smoking and the others I mentioned above, and also from factors like socioeconomic status and reported levels of life satisfaction. They found a striking result. Over the nine-year period, those who’d placed low on the index were twice as likely to die as individuals who were similar with regard to other factors but had placed high on the social network index. Apparently, hermits are bad bets for life insurance underwriters.

Excerpted from “Subliminal: How Your Unconscious Mind Rules Your Behavior.” by Leonard Mlodinow. Copyright © 2012 by Leonard Mlodinow. Excerpted by permission of Pantheon, a division of Random House, Inc. All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.

Many voters who go to the polls to support Amendment One will do so believing outright falsehoods about same-sex marriages and civil unions. In particular, they hold the belief that such partnerships are damaging to the health and well-being of the children raised in them. That is, after all, one of the chief justifications for the amendment.

According to the pro-Amendment One group Vote for Marriage NC, for instance, “the overwhelming body of social science evidence establishes that children do best when raised by their married mother and father.” If marriage is defined as anything other than the union between man and woman, the group adds, we will see “a higher incidence of all the documented social ills associated with children being raised in a home without their married biological parents.”

“Overwhelming body of social science evidence”? “Documented social ills”? Is this really true? Are same-sex marriages and civil unions bad for kids?

Well, no. Indeed, as I report in my new book ”The Republican Brain: The Science of Why They Deny Science — and Reality,” the claim that the kids won’t be all right in same sex marriages or partnerships now rates up there with a number of other hoary old falsehoods about homosexuality: the assertion that people can “choose” whether to be gay; the notion that homosexuality is a type of disorder; and the wrong idea that it can be cured through “reparative” therapy. All of these claims are explicitly disavowed by the American Psychological Association (APA).

In a moment, I want to explore the underlying psychology behind how conservatives, especially religious ones, can believe such falsehoods. But first, let’s dismantle, on a substantive level, the idea that research shows that kids fare worse when raised by two parents who are of the same gender.

According to the APA, the relevant science shows nothing of the kind. “Beliefs that lesbian and gay adults are not fit parents … have no empirical foundation,” concludes a recent publication from the organization. To the contrary, the association states, the “development, adjustment, and well-being of children with lesbian and gay parents do not differ markedly from that of children with heterosexual parents.”

So how can Christian conservatives possibly claim otherwise?

Well, one favored approach is literally citing the wrong studies. There is, after all, a vast amount of research on kids in heterosexual two-parent families, and mostly these kids do quite well — certainly better than kids in single-parent families (for obvious reasons). Christian conservatives cite these studies to argue that heterosexual families are best for kids, but there’s just one glaring problem. In the studies of heterosexual two-parent families where children fare well, the comparison group is families with one mother or one father — not two mothers or two fathers. So to leap from these studies to conclusions about same-sex parenting, explains University of Virginia social scientist Charlotte Patterson, is “what we call in the trade bad sampling techniques.”

But wait: Don’t Christian conservatives want to be factually right and to believe what’s true about the world? And shouldn’t a proper reading of this research actually come as a relief to them and help to assuage their concerns about dangerous social consequences of same-sex marriage or civil unions? If only it were that simple. We all want to be right and to believe that our views are based on the best available information. But in this case, Christian conservatives utterly fail to get past their emotions, which powerfully bias their reasoning. Indeed, science doesn’t just demonstrate that the kids are all right in same-sex unions. It also shows how and why some people reason poorly in highly politicized cases like this one — and, in the case of the anti-gay views of Christian conservatives, rely on their gut emotions to come up with wrong beliefs. Here’s how it works.

There are a small number of Christian right researchers and intellectuals who have tried to make a scientific case against same-sex marriages and unions by citing alleged harms to children. This stuff isn’t mainstream or scientifically accepted — witness the APA’s statements on the matter. But from the perspective of the Christian right, that doesn’t really matter. When people are looking for evidence to support their deeply held views, the science suggests that people engage in “motivated reasoning.” Their deep emotional convictions guide the retrieval of self-supporting information that they then use to argue with, and to prop themselves up. It isn’t about truth, it’s about feeling that you’re right — righteous, even.

And where, in turn, do these emotions come from? Well, there’s the crux. A growing body of research shows that liberals and conservatives, on average, have different moral intuitions, impulses that bias us in different directions before we’re even consciously thinking about situations or issues. Indeed, this research suggests that liberals and conservatives even have different bodily responses to stimuli, of a sort that they cannot control. And one of the strongest areas of difference involves one’s sensitivity to the feeling of disgust.

A recent study, for instance, found that “individuals with marked involuntary physiological responses to disgusting images, such as of a man eating a large mouthful of writhing worms, are more likely to self-identify as conservative and, especially, to oppose gay marriage than are individuals with more muted physiological responses to the same images.” In other words, there’s now data to back up what we’ve always kind of known: The average conservative, much more than the average liberal, is having visceral feelings of disgust toward same-sex marriage. And then, when these conservatives try to consciously reason about the matter, they seize on any information to support or justify their deep-seated and uncontrolled response — which pushes them in the direction of believing and embracing information that appears to justify and ratify the emotional impulse.

And voila. Suddenly same-sex marriages and civil unions are bad for kids. How’s that for the power of human reason?

All people engage in emotion-guided or -motivated reasoning, to be sure. But mounting evidence suggests that the Left and Right may do so differently. And they definitely do so for different reasons — as the present case so strongly demonstrates.

Does this mean we should be more tolerant of the intolerant, or less disgusted by those who may consider us disgusting? Maybe. After all, people may not have much control over these impulses. They may not even be aware of them. At the very least, such knowledge should increase our level of understanding of those who disagree with us.

In the end, however, facts are facts — and emotions and gut instincts are an utterly unreliable way of identifying them. We can try to be understanding of people different from us — even when they’re manifestly failing at the same task. But the latest research makes it more untenable than ever to base public policy on gut-driven misinformation.

That has implications for our political world. In a recent interview, Chris Mooney, author of “The Republican Brain,”explained, “The amygdala plays the same role in every species that has an amygdala. It basically takes over to save your life. It does other things too, but in a situation of threat, you cease to process information rationally and you’re moving automatically to protect yourself.”

The finding also fits with other data. Mooney discusses studies conducted at the University of Nebraska-Lincoln in which self-identified liberals and conservatives were shown images – apolitical images – that were intended to elicit different emotions. Writing at Huffington Post, Mooney explains that “there were images that caused fear and disgust — a spider crawling on a person’s face, maggots in an open wound — but also images that made you feel happy: a smiling child, a bunny rabbit.” The researchers noted two differences between the groups. The researchers studied their subjects’ reactions by tracking their eye movements and monitoring their “skin conductivity” – a measure of one’s autonomic nervous system’s reaction to stimuli.

Conservatives showed much stronger skin responses to negative images, compared with the positive ones. Liberals showed the opposite. And when the scientists turned to studying eye gaze or “attentional” patterns, they found that conservatives looked much more quickly at negative or threatening images, and [then] spent more time fixating on them.

Mooney concludes that this “new research suggests [that] conservatism is largely a defensive ideology — and therefore, much more appealing to people who go through life sensitive and highly attuned to aversive or threatening aspects of their environments.”

But those cognitive biases are only part of the story of how a political movement in the wealthiest, most secure nation in the world have come to view their surroundings with such dread. The other half of the equation is a conservative media establishment that feeds members of the movement an almost endless stream of truly terrifying scenarios.

The phenomenon of media “siloing” is pretty well understood – in an era when dozens of media sources are a click away, people have a tendency to consume more of those that conform to their respective worldviews. But there is some evidence that this phenomenon is more pronounced on the right – conservative intellectuals have had a long-running debate about the significance of “epistemic closure” within their movement.

So conservatives appear to be more likely to be hard-wired to be highly sensitive to perceived threats, and their chosen media offers them plenty. But that’s not the whole story because of one additional factor. Since 9/11, and especially since the election of President Barack Obama, one of the most significant trends in America’s political discourse is the “mainstreaming” of what were previously considered to be fringe views on the right. Theories that were once relegated to the militia movement can now be heard on the lips of elected officials and television personalities like Glenn Beck.

Consider, then, what it must be like to be a true-blue Rush Limbaugh fan, or someone who thinks Michele Bachmann is a serious lawmaker with a grasp of the issues – put yourself into that person’s shoes for a moment, and consider what a nightmarish landscape the world around them must represent:

The White House has been usurped by a Kenyan socialist named Barry Soetero, who hatched an elaborate plot to pass himself off as a citizen of the United States – a plot the media refuse to even investigate. This president doesn’t just claim the right to assassinate suspected terrorists who are beyond the reach of law enforcement – he may be planning on rounding up his ideological opponents and putting them into concentration camps if he is reelected. He may have murdered a blogger who was critical of his administration, but authorities refuse to investigate. At the very least, he is plotting on disarming the American public after the election, in accordance with a secret deal cut with the UN and possibly with the assistance of foreign troops.

Again, these ideas are not relegated to the fringe of forwarded emails. Glenn Beck talked about FEMA camps on Fox News (he later debunked them, which only fueled charges of a media coverup); dozens of Republican elected officials have at least hinted that they are birthers, while an erstwhile front-runner for the GOP nomination has repeatedly claimed that Obama is not eligible to be president. The head of the NRA, and the GOP’s presidential nominee have both claimed Obama is plotting to take Americans’ guns.

In reality, Americans are safer and more secure today than at any point in human history. But inhabitants of the world of the hard-right are surrounded by danger – from mobs of thugs at home to a variety of powerful and deadly enemies abroad.

For the true believers, Latin American immigration isn’t a phenomenon to be managed, but a grave existential threat. A plot to “take back” large swaths of the Southwest is a theory that has aired not only on obscure right-wing blogs, but on Fox and CNN. On CNN, Lou Dobbs claimed immigrants were spreading leprosy; Rick Perry, Rep. Louie Gohmert and other “mainstream” voices on the right (that is, people with platforms) agree that Hezbollah and Hamas “are using Mexico as a way to penetrate into the southern part of the United States,” possibly with the aid of “terror babies” carried in pregnant women’s wombs.

In the real world, the rate of violent crime in the US is at the lowest point since 1968 – in fact, it is somewhat of a mystery that the violent crime rate has continued to decline even in the midst of the Great Recession. It’s also true that 84 percent of white murder victims are killed by other whites. But if you read the Drudge Report, or check in at Fox, on any given day you will see extensive coverage of any incident in which a black person harms a white person. These fit in with the narrative – advanced by people like Glenn Beck and long-touted by Ron Paul – that we stand on the brink of a race war, led by the New Black Panthers (just consider how frightening it would be if there were more than a dozen New Black Panthers, or if they did more than say stupid things). Marauding “flash-mobs” of black teens – a near-obsession at many conservative outlets these days — are simply a harbinger of things to come.

Continue, for a moment, to stroll in the shoes of a true believer on the right. Imagine how frightening it would be to believe Frank Gaffney, a former Assistant Secretary of Defense in the Reagan administration and leading neoconservative voice, when he claims the Muslim Brotherhood has infiltrated the highest levels of the US government, or Newt Gingrich, when he says that “sharia law” (there isn’t such a thing in the way conservatives portray it – as a discrete canon of laws) poses a grave threat to our way of life.

Imagine believing that the Democrats’ business-friendly insurance reforms included panels of bureaucrats who would decide when to let you die, as Sarah Palin infamously suggested. Or that virtually the entire field of climatology is perpetrating a “hoax,” as senator James Inhofe claims, in order to undermine capitalism and impose a one-world government. Imagine seeing energy-efficient light bulbs as part of an international plot to, again, undermine capitalism, as Michele Bachmann believes. Imagine thinking that the public school system “indoctrinates” young children into the “gay lifestyle,” as influential members of the religious right – James Dobson, Bryan Fischer, Anita Bryant – have claimed for years. Imagine believing our electoral system is tarnished by massive voter fraud or that union thugs are running amok or that the Department of Homeland Security is making a list of people who advocate for “limited government.” Imagine if there really were a War on Christmas!

These dark narratives come in addition to more run-of-the-mill fear-mongering about the Iranian “threat,” or nonsense about how “entitlements” are leading our economy to look like Greece’s. Those of us in the “reality-based community” may look at these specters haunting the right with exasperation or amusement, but just consider for a moment how bleak the world looks to those who buy into these ideas.

Perhaps the most frightening part of all of this for the true believers is that even though these things aren’t just fringe ideas circulating in forwarded emails – they’re discussed by influential politicians and on leading cable news outlets – the bulk of the media and most elected officials refuse to investigate what’s happening to this country.

That one ideological camp is so consumed with fear also has a lot to do with why conservatives and liberals share so little common ground. Progressives tend to greet these narratives with facts and reason, but as Chris Mooney notes, when your amygdala is activated, it takes over and utterly dominates the brain structures dedicated to reason. Then the “fight-or-flight” response takes precedence over critical thinking.

In his previous sally, he cited the story of Maria’s Shoe, a tall tale that has been circulating in the New Age community for decades, always growing in the telling. This story is the claim that a woman with a heart condition was hospitalized, and while unconscious with a heart attack, her spirit floated out of the coronary care unit to observe a shoe on a third-floor ledge. As has been shown, she described nothing that could not be learned by mundane observation, no supernatural events required, and further, that the story is peculiarly unverifiable: “Maria” cannot be found, not even in the hospital records, and no one has been found who even knew this woman. The entire story is hearsay with no independent evidence whatsoever.

Beauregard attempts to salvage the story by layering on more detail. The description of the shoe was very specific, he says, right down to the placement of the laces and the pattern of wear, and she could not possibly have learned this by overhearing staff talking about it because “it would have been difficult for Maria to understand the location of the shoe in the hospital and the details of its appearance because she spoke very little English.” This is a curious observation; the claim is that she could not understand a description of the shoe, but she was able to describe the shoe herself to a woman, Kimberly Clark Sharp, who did not understand Spanish.

“When I got to the critical-care unit, Maria was lying slightly elevated in bed, eyes wild, arms flailing, and speaking Spanish excitedly,” recounts Sharp. “I had no idea what she was saying, but I went to her and grabbed her by the shoulders. Our faces were inches apart, our eyes locked together, and I could see she had something important to tell me.”

The question isn’t whether a seriously ill woman with poor command of English could see the shoe; it’s whether a healthy, ambulatory, English-speaking woman who has made a career out of the myth of NDEs could see the shoe. Beauregard’s additions to the anecdote do not increase its credibility at all.

Beauregard adds another anecdote to the litany, the story of another cardiac patient who was resuscitated and later recounted seeing a particular nurse while his brain was not functional. Seriously — more anecdotes don’t help his case. He threatens to have even more of these stories in a book he’s in the process of publishing, but there’s no point. He could recite a thousand vague rumors and poorly documented examples with ambiguous interpretations, and it wouldn’t salvage his thesis.

This new anecdote is more of the same. The patient is comatose and with no heart rhythm when brought into the hospital; over a week later, he claims to recognize a particular nurse as having been present during his crisis, and mentions that she put his dentures in a drawer.

I am underwhelmed. I must introduce Beauregard to two very common terms that are well understood in the neuroscience community.

The first is confabulation. This is an extremely common psychological process in which we fill in gaps in our memory with fabrications. I described this in my previous response, but Beauregard chose to disregard it. The patient above has a large gap in his memory, but he knows that he existed in that period, and something must have happened; he knows that he was resuscitated in a hospital, so can imagine a scene in which he was surrounded by doctors and nurses; he knows that his dentures are missing, so he suspects that someone put them somewhere, likely one of the people surrounding him during the emergency. So his brain fills in the gap with a plausible narrative. This whole process is routine and unsurprising, and far more likely than that his mind went wandering away from his brain.

The second term is confirmation bias. Only positive responses that confirm Beauregard’s expectations are noted. The patient guessed that a nurse he met during his routine care was also present during his episode of unconsciousness, and he was correct. What if he’d guessed wrongly? That event would be unexceptional, nobody would have made note of it, and Beauregard would not now be trotting out this incident as a vindication of his hypothesis. This is one of the problems of building a case on anecdotes; without knowledge of the range and likelihood of various results, one can’t distinguish the selective presentation of chance events from a measurable phenomenon.

While unaware of basic concepts in science, Beauregard seems to readily adopt the most woo-ish buzzwords. His explanation for this purported power of the mind to exist independently of any physical substrate is, unfortunately and predictably, quantum mechanics. Every charlatan in the world seems to believe that attaching “quantum” to a word makes it magical and powerful and unquestionable. I have to accept Terry Pratchett’s rebuttal: “‘Let’s call it Quantum!’ is not an explanation.” And neither is Beauregard’s feeble insistence that the universe possesses quantum consciousness, that psychic powers represent quantum phenomena, or that there is an infinitely loving Cosmic Intelligence.

Beauregard then accuses me of having an ideological bias, and that I’m a fanatical fundamentalist. He, of course, is the dispassionate, objective observer with no ax to grind, only interested in reporting the scientific facts. Unfortunately, his book “The Spiritual Brain” reveals to the contrary that he has some very, very strange beliefs.

Individual minds and selves arise from and are linked together by a divine Ground of Being (or primordial matrix). That is the spaceless, timeless, and infinite Spirit, which is the ever-present source of cosmic order, the matrix of the whole universe, including both physics (material nature) and psyche (spiritual nature). Mind and consciousness represent a fundamental and irreducible property of the Ground of Being. Not only does the subjective experience of the phenomenal world exist within mind and consciousness, but mind, consciousness, and self profoundly affect the physical world…it is this fundamental unity and interconnectedness that allows the human mind to causally affect physical reality and permits psi interaction between humans and with physical or biological systems. With regard to this issue, it is interesting to note that quantum physicists increasingly recognize the mental nature of the universe.

If I am an ideologue, it’s only in that I demand that if you call something science, it bear some resemblance in method and approach to science, not mysticism. Beauregard insists on trying to endorse the babbling piffle above as science by reciting the number of publications he has made, and how much grant money he’s got, when I’m looking for verifiable, reproducible, measurable evidence.

I would also remind him that Isaac Newton, who was probably an even greater scientist than the inestimable Beauregard, wasted much of his later years on mysticism, too: from alchemy and the quest for the Philosopher’s Stone, to arcane biblical hermeneutics, extracting prophecies of the end of the world from numerological analyses of Revelation. While his mechanics and optics have stood the test of time, that nonsense has not. That his mathematics and physics are useful and powerful does not imply that he was correct in his calculation that the world will end before 2060 AD; similarly, Beauregard’s success in publishing in psychiatry journals does not imply that his unsupportable fantasies of minds flitting about unfettered by brains is reasonable.