Prejudice in the brain

Despite the great strides that have been made toward a more egalitarian society in the United States over the past 50 years, events like what occurred in Ferguson last month are a bleak reminder of the racial tensions that still exist here. Of course, the United States is not alone in this respect; throughout the world we can see abundant examples of strain between different races, as well as between any groups with dissimilar characteristics. In fact, it seems that the quickness with which we form a negative opinion about those who are not members of the same group as us may be characteristic of human nature in general, as its effects have been pervasive throughout history, and it persists even when we attempt fastidiously to stamp it out.

Indeed, it may be that our inclination towards prejudicial thinking has its roots in what was once an adaptive behavior. Some argue that our ancient hominid ancestors may have benefited from living in small groups, as this allowed for joint efforts in gathering and protecting resources. A logical offshoot of the development of group living would have been the emergence of skill in being able to tell members of your group apart from those who were not. It might have paid off to be wary of those who were not part of your group, as they would have been more likely to pose a threat. According to this evolutionary hypothesis, prejudice--which can be defined as an opinion of someone that is formed based on their group membership--may be the result of this strategy being so effective in the past. In essence, we may be saddled with the mindset of our evolutionary ancestors, which makes us more skeptical at first of anyone whom we see as "different" than us.

Prejudice and the amygdala

If prejudice is a deep-seated human behavior, it would not be surprising to find networks in the brain that are selectively activated when someone has xenophobic thoughts. One area of the brain that has been investigated in this context is the amygdala.

The amygdala is often associated with emotion, and is perhaps best known for its role in fear and the recognition of threats. If you were walking in the woods and saw a bear, your amygdalae would immediately become activated, helping to bring about a fear response that would encourage you to run away (or maybe cause you to freeze in place).

Several neuroimaging studies have looked at what happens in the brains of people when they see images of others outside of their racial group (e.g. white people looking at images of black faces). Some findings from these studies include: the amygdala is activated upon seeing such images, amygdala activation is correlated with xenophobic attitudes of the viewer, and amygdala activity in white people is higher when viewing black faces with darker skin tone.

Thus, the amygdala may serve as a threat-detection mechanism that is reflexively activated when we see an outsider. Perhaps because this has been adaptive in the past, it may act to put our brain on alert when someone outside of our racial group is near. In many societies today, however, where we are attempting to make racial divisions less distinct, this knee-jerk reaction seems to be counterproductive.

Prejudice and the insula

Another area of the brain that has been associated with prejudice in neuroimaging studies is the insula. The insula is also involved in processing emotional states, and has been linked to mediating feelings of social disapproval. For example, one study found that the insula and amygdala were activated in individuals while they viewed pictures of of people deemed to be social outcasts, such as homeless people or drug addicts. Because the insula is also activated when viewing pictures of people outside one's racial group, it has been hypothesized that the insula is involved in feelings of distaste that may arise when experiencing prejudicial thoughts.

Prejudice and the striatum

The striatum, a subcortical area thought to play an important role in reward processing, also has been implicated in prejudice--albeit in a very different way than the amygdala and insula. Activity in the striatum correlates with rewarding experiences, and neuroimaging studies have found that the striatum is also activated when looking at pictures of individuals from one's own racial group. When white participants were tested for implicit preferences (i.e. preferences they may not state or even be aware of, but that they still seem to possess) for people of their own race, activity in the striatum was stronger in response to white faces in those who scored higher on the test for implicit preferences.

Thus, there may be activity in the brain that reinforces our tendency toward prejudice in at least two ways: 1) we may be more likely to feel fear and aversion when seeing someone of another race, and 2) we may be more likely to experience positive emotions in response to seeing someone of our own race.

So, if there are structures in our brains that promote prejudice, does it mean attempts to reduce our prejudices--both individually and societally--are a lost cause? Of course not. Just as there are brain structures that may make us more likely to recognize differences, there are also structures (e.g. areas of the frontal cortex) that allow us to exert control over those potentially reflexive reactions.

It's possible that the recognition of deep-seated mechanisms for prejudice could help us to understand racism a little better. It could, for example, provide insight into why people in high-stress situations may be more likely to see things as divided down racial lines. For, if their brains are already inclined to see people of another race as more threatening and they are in a stressful situation, they may be quicker to identify someone of a different race as the threat.

However, the extent to which such innate responses to outsiders affects our behavior is still somewhat unclear, and the hypothesis that such responses are remnants of once-adaptive behavior is just that: a hypothesis. For practical purposes, it may not matter exactly what the basis of prejudicial thinking is, as we are certain it's a thought pattern that doesn't have much remaining value in today's world. However, being open to the idea that we have some inclinations toward prejudicial thinking may help us to be able to train people to more mindfully deal with high-stress interactions with people of another race. For, instead of pretending these prejudicial thoughts don't (or shouldn't) happen, it would allow us to focus more on ways to mitigate the damage that might occur when they do.

Amodio DM (2014). The neuroscience of prejudice and stereotyping. Nature reviews. Neuroscience PMID: 25186236

Why do I procrastinate? I'll figure it out later

Procrastination

If you are a chronic procrastinator, you're not alone. Habitual procrastination plagues around 15-20% of adults and 50% of college students. For a chronic procrastinator, repeated failure to efficiently complete important tasks can lead to lower feelings of self-worth. In certain contexts, it can also result in very tangible penalties. For example, a survey in 2002 found that around 40% of American tax-payers procrastinated on their taxes, resulting in errors due to rushed filing that cost an average of $400 per procrastinator. More importantly, we tend to procrastinate when it comes to medical care (both preventive and therapeutic), which can involve very real costs to our well-being.

Why is the urge to procrastinate so strong? It sometimes seems that we are compelled to procrastinate by a force that is disproportionate to the small reward we may get from putting off a task we're not looking forward to. According to Gustavson et al., the authors of a study published last week in Psychological Science, a predisposition to procrastinate may have its roots in our genes.

Previous research has suggested a potential link between a tendency to procrastinate and an impulsive nature. Gustavson et al. explored this possible connection by observing the traits of procrastination and impulsivity in a group of 181 identical and 166 fraternal twins. Because identical twins share 100% of their genes and fraternal twins only share around 50% of their genes, if a trait is shared by identical twins more frequently than it is by fraternal twins, it suggests the trait has a significant genetic basis (for more on twin studies see this post).

The investigators reported a significant correlation between procrastination and impulsivity (r = .65). The group also reported that their genetic model determined that procrastination and impulsivity were perfectly correlated (r = 1.0), suggesting that the genetic influences on procrastination and impulsivity might be completely shared. In other words, according to this study, there are no genetic influences on procrastination that aren't also affecting impulsivity.

But why would these two traits be associated with one another? Procrastination involves putting things off, while impulsivity involves doing them on a whim. Gustavson et al. suggest that both procrastination and impulsivity involve a failure in goal management and a deficit in the ability to guide behavior effectively using goals. The authors refer to a hypothesis proposed by procrastination researcher Piers Steel that suggests impulsivity may have been adaptive to our ancient ancestors when survival depended more on thinking and acting quickly. In today's much safer world, however, planning for events yet to come has superceded impulsivity in terms of importance.

Thus, like many of our other bad habits, procrastination may have its roots in a behavior that was at one point adaptive and is now outdated. So, if it feels like your desire to procrastinate is driven by a force much stronger than your willpower, it may be so. If Gustavson et al. are correct, the impetus for procrastination lies in genetic programming that dates back to the Pleistocene era.

Gustavson, D., Miyake, A., Hewitt, J., & Friedman, N. (2014). Genetic Relations Among Procrastination, Impulsivity, and Goal-Management Ability: Implications for the Evolutionary Origin of Procrastination Psychological Science DOI: 10.1177/0956797614526260

Is your biological clock ticking? Maybe you should ignore it

As I've transitioned into middle age, I've gotten used to seeing my Facebook feed filled with baby pictures, descriptions of charming family outings, and adorable quotations from the mouths of toddlers. If I knew nothing about what it were like to have a child (mine is just finishing up the terrible twos), I would assume from scrolling through these perfectly tailored social media portraits of others' lives that having kids is a non-stop fun-filled procession of treasured moments. Of course, this perspective is not confined to my Facebook news feed. It's common knowledge that children make us happier and help us to feel more fulfilled.

This is one of many instances, however, where research and folk wisdom don't mesh. In fact, when studies have compared the happiness of those with children to the happiness of those without children, they have often found that having children is associated with lower life satisfaction. A recent publication looked at data from close to 1.8 million Americans and over a million other respondents throughout the world. What the researchers (a psychologist and an economist--both from Princeton) found generally supported the idea that those who have children are not as happy as those who do not.

There are many explanations for such a finding other than the hypothesis that kids make us miserable. For example, although the survey data used by the Princeton researchers indicated lower life satisfaction in people with children, people with children also experienced less physical pain, felt they had more enjoyment in their lives, earned higher incomes, were better educated, and were healthier. On the other hand, they experienced more stress, worry, and anger. Thus, it may be that having children generates its share of highs and lows, causing us periods of intense stress and upset that are relieved by the enjoyment we get from spending time with our kids. Most parents would probably agree with this statement to some extent.

Regardless, if the data indicates that people with kids are--in a best case scenario--no happier than those without, then where do we get this idea that having kids will make us happier? And why, when we talk to people with kids (or see their posts on Facebook), are we given the distinct impression that a life without children is somehow...lacking?

 

Survival of the Fittest

The answer to this conundrum may involve evolution. Of course, because having children is the only way to directly pass on one's genetic lineage, then the act of having children causes the propagation of a genetic makeup that may predispose someone to look favorably upon having children. In other words, if there were genes that affected someone's personality in such a way that they loathed the idea of having children, then those genes wouldn't last very long in the population because the reluctance of those who possessed them to have children would naturally limit their propagation.

Although genes that predispose one for parenthood may be part of the answer to this puzzle, there also may be a role for another unit of transmission: the meme. The term meme was coined by Richard Dawkins in his revolutionary book about genetics called The Selfish Gene. A meme is an idea. The idea can be represented by a cultural norm, a style, a behavior, or anything else that can be spread from person to person and generation to generation. Just like genes, however, memes are subject to natural selection.

For example, the rock group Bad English recorded a song 25 years ago called "When I See You Smile." You may or may not remember this song depending on your age and how often you listened to top-40 music in 1989. Here's a link to the video if you care to refresh your memory and/or reminisce. Bad English's song could be considered to have moderately good "fitness" as a meme. It was an idea that enjoyed brief popularity, and at the height of its popularity a significant percentage of the world's English-speaking population was aware of its existence (and maybe even sung along once or twice). However, I don't expect anyone will be singing it 100 years from now.

In contrast, the lyrics to Auld Lang Syne came from a Robert Burns poem written way back in 1788. Over 225 years later, the song is known in many countries throughout the world and sung regularly at events like the beginning of the new year or any other occasion that signals the end of a period of time (e.g. funerals, graduations). The song is easy to remember, has a meaning (the symbolism of endings and beginnings) that resonates with people regardless of their culture, and is sung to a tune that is easy to reproduce. Auld Lang Syne is an extremely "fit" meme.

Although songs may be somewhat trivial examples of memes (contrasted with examples like organized religion or language), the difference between the longevity of these two songs suggests that some memes seem to be better at replicating than others. With that in mind, lets turn back to the idea that having children is an enriching experience. There isn't a much better way for a meme to ensure its survival than if holding it as a belief makes people more likely to engage in behavior that will lead to its own propagation. Believing in the idea that children bring happiness makes one more likely to have children. Those offspring then provide another set of impressionable minds who are readily convinced by their child-having parents and grandparents that children are the greatest source of joy in the world. And the meme continues to spread.

Genes don't necessarily have to promote health to allow them to continue to be propagated, but they have to have some quality that promotes their own transmission. Memes work the same way. They don't need to be accurate ideas, but there has to be something driving their dissemination. Could it be that our belief in the wonder of childbearing is simply due to the success of this meme in promoting its own transmission?

It's possible. As Daniel Gilbert discusses in his investigation of the errors we commit in deciding what will make us happy, Stumbling On Happiness, it would not be the first meme that led us astray. For example, the meme that great wealth leads to happiness continues to thrive throughout much of the world. Evidence suggests, however, that once one has enough money to ensure one's basic needs are provided for, additional money does little to contribute to one's satisfaction.

So, if you're childless and experiencing pangs of jealousy over the seemingly perfect family photos your friends are posting to Facebook, remember that the research suggests your friends aren't as happy as they look in those photos. And maybe you don't have children because you just haven't been suckered into the mass delusion that children will make your life complete.

Deaton, A., & Stone, A. (2014). Evaluative and hedonic wellbeing among those with and without children at home. Proceedings of the National Academy of Sciences, 111 (4), 1328-1333 DOI:10.1073/pnas.1311600111