The CCSN Insider

Monthly Blogs on Cognitive and Social Neuroscience

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The Growing Debate Over “Same-Stuff” Static

by Rebecca Steinberg

“Same-Stuff” static is the electricity generated when two objects of the same material are rubbed against one another. We see it on a day-to-day basis in lightning, the generation of powders, and explosions. Despite its prevalence in our daily lives, the mechanisms behind these phenomena have been called into question.

In the traditional understanding of same-stuff static, two insulating materials hold onto electric charges of different strengths. If the objects of the same material are the exact same size, each object holds the same amount of charge. When the sizes of these objects differ, the possibility of the charges held transferring increases, thus generating static electricity. 

What was believed initially was that valence electrons in a higher energy perch at the surface of one object interlocked with lower energy levels on the surface of the other object. The difference in sizes of the objects is important when considering the number of electrons that can be transferred.

Physicist Heinrich Jaeger at the University of Chicago is calling this idea into question. Jaeger tested this theory with the static found among small zirconium dioxide-silicate beads. Smaller beads were negatively charged, while larger beads were positively charged. But the number of valence electrons available for transmission on each bead did not correlate exactly with the amount of static electricity generated, suggesting that there is some other mechanism at play. The beads possessed too few valence electrons to explain the static. 

Jaeger suggests that the extra electrons needed to generate static may be derived from hydroxide ions in a layer of water one molecule thick, or in the zirconium metal itself. Although more extensive research is required to pinpoint the exact source of extra electrons, the impact of this information could be useful for pharmaceutical initiatives in the future. 

References:

  Cho, A. (June 10, 2014). Static Electricity Defies Simple Explanation. Science/AAAS. http://news.sciencemag.org/chemistry/2014/05/static-electricity-defies-simple-explanation

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Unmasking Male Odor as a Confounder

by Rebecca Steinberg

Nearly all studies using animal models can be impacted by an animal’s stress level. Jeffrey Mogil’s group at McGill University noticed an extraordinary connection between the gender of an experimenter and how it confounded with their study on pain measurement.

Mice showed fewer signs of physical pain when in the presence of male researchers when measuring the intensity of their grimace. This observation is not merely based on the sight of a male, but is even offset by the odor of the experimenter. Mogil, et al. placed male and female odor-ridden T-shirts within the lab room and found a similar effect.

This decrease in pain was not merely a masking of pain, but an actual physical decrease in pain, according to Mogil’s group. This was measured by the amount of stress hormone released, the amount of fecal matter deposited, and the animal’s body temperature, among other methods. Mogil believes that this natural painkiller is part of a primordial response, established for eons. It may be an instinctive attempt to not appear weak in front of a threatening presence.

Stress levels are critical to the establishment of animal behavior. In a stressful environment, any recorded responses may differ vastly from responses in a relaxed state of mind. This may be a cause for the inability for certain labs to replicate studies (Grimm, D). There may even be human applications for this information, in comparing the pain responses to treatment by a male or female physician.

Future studies should take this confounder into consideration. The findings by Mogil, et al. serve as an eye-opening reminder of the many detailed factors that can make or break the results of an experiment.

  References:

  Grimm, D. (2014). Male Scent May Compromise Biomedical Research. Science/AAAS 3 May 2014. < http://news.sciencemag.org/brain-behavior/2014/04/male-scent-may-compromise-biomedical-research>.

  Sorge, RE, Loren, JM, Isbester, KA, Sotocinal, SG, Rosen, S, Tuttle, AB, Wieskopf, JS, Acland, EL, Dokova, A, Kadoura, B, Leger, P, Mapplebeck, JCS, McPhail, M, Delaney, A, Wigerblad, G, Schumann, AP, Quinn, T, Frasnelli, J, Svensson, CI, Sternberg, WF, Mogil, JS. (2014)  Olfactory exposure to males, including men, causes stress and related analgesia in rodents. Nat Meth 2014/04/28 online. http://www.nature.com/nmeth/journal/vaop/ncurrent/full/nmeth.2935.html. 

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Sensitivity to justice and the moral brain

by Rebecca Steinberg

When acts of help or harm evoke a sense of justice within a person, it is readily assumed that individuals who are emotional will display greater moral judgment. This seems to make sense, with our understanding of justice and placing ourselves in the “shoes of others” emotionally. We presume that our associations with justice stem from a more emotive origin in the brain than logical.

However, a recent study by Keith Yoder and Dr. Jean Decety questioned this assumption. They compared the sensitivity to justice of each participant to the amount of moral judgment they depicted in a given scenario. As predicted, those who were more sensitive to justice provided stronger moral feedback than those who were less justice sensitive. For example, if a harmful scenario was presented, those who were more justice sensitive placed more blame on the individual committing the act than those who were less justice sensitive.

Yoder and Decety explored this connection further, using fMRI scanning to try to grasp the neural mechanisms behind moral evaluation in subjects with varying justice sensitivity. The results were unexpected. Instead of displaying more activity in emotional pathways within the brain, cognitive regions were significantly more active when evaluating morally-laden behavior in more justice sensitive participants.

The study predicted that if affect were more influential in moral judgment, salient systems underpinning emotional saliency would be more active. On the other hand, if cognitive processing were more influential, then executive regions would be more active. Surprisingly, in participants with a higher sensitivity to justice, executive neural networks displayed more activity, suggesting that cognitive components play a large role in moral judgments. Contrary to common sense intuitions, individuals sensitive to justice and fairness are driven by reason and not by emotion. The findings by Decety and Yoder underscore the incredible complexity of the brain and how there is still much to be understood about its neuronal underpinnings.

References:

  Yoder, KJ, Decety, J (2014) The Good, the Bad, and the Just: Justice Sensitivity Predicts Neural Response during Moral Evaluation of Actions Performed by Others. J. Neurosci 34(12):4161-4166.

  Ingmire, J. (2014) Brain scans link concern for justice with reason, not emotion. Web. http://news.uchicago.edu/article/2014/03/27/brain-scans-link-concern-justice-reason-not-emotion?utm_source=newsmodule

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Long-term deficiencies require long-term study

by Rebecca Steinberg

Treatment of a stroke is generally centered on the immediate consequences of a stroke, namely the sensorimotor impacts and mechanics of speech. Less focus is placed on the lasting cognitive effects of a stroke. Deborah Levine, MD, MPH, et al. from the University of Michigan found that stroke victims lose global cognition and executive function at a faster rate than elderly individuals who hadn’t experienced a stroke.

Stroke has an apparent relationship to mental decline, according to the analysis by Levine. A drop in cognition unsurprisingly appeared at the time of stroke, but was followed by a steady and fast cognition decline in subsequent years. Executive function, or connecting the present with past experiences, did not show an immediate decline after stroke, but decreased subsequently.

Rehab focuses on correcting the obvious, mechanical consequences of stroke, but it has been found that potentially less recoverable functions of cognition should be an added application of treatment. Cognitive therapies appear to have only a modest effect on improving lost cognitive function, and the longevity of these treatments is in question. The findings in Levine’s study might be strengthened with increased follow-up for stroke patients. It is certainly easier to identify the immediate, obvious effects of stroke, but the greatest impacts of a disease dealing with cognitive function might not be as readily assessed.

Further studies might consider the factors that lead to stroke and their impact on cognitive decline. Is there a prior cause of stroke that is linked with other illnesses to generate mental decline? A greater focus on long-term effects of illness might be a concept applied to diseases beyond stroke.  Do other diseases exist that require more extensive follow-up methods in order to fully understand any accompanying loss of function?  Finally, what rehabilitation therapies are most effective for treating something as complex as cognitive dysfunction and its decline?

  References:

  Phend, C. (2014). Stroke Speeds Long-Term Brain Deficits. MedPage Today. http://www.medpagetoday.com/MeetingCoverage/ISCNeuroEdition/44342?xid=nl_mpt_AAN_confreporter_2014-02-18&utm_source=aan-confreporter&utm_medium=email&utm_content=mpt&utm_campaign=18%7C02%7C2014&userid=&eun=g5968703d8r&[email protected]&mu_id=5968703.

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Epigenetics: Why identical twins aren’t identical at all

by Rebecca Steinberg

Epigenetics is the study of heritable genetic activity without alteration to the DNA sequence. It can also apply to stable, long term changes in transcriptional regions of a cell. Epigenetics is a term that has been liberally tossed around in the scientific community, but what exactly constitutes the phenomenon of epigenetics? Three traits of an epigenetic system must be present: the changes must be heritable, self-perpetuating, and reversible. Among commonly referenced phenomenon are prions, DNA methylation, nucleosome locations, histone modification, and noncoding RNA. But how can we accurately use the term epigenetics in a clinical context?

Epigenetic studies are of particular interest with regards to genetic variations not explained by differences in genome sequence. Epigenetic research has been sited in several genetic disorders, primarily with regards to imprinting, or the selective “on-off switching” of specific genes, chromosomes, or parts of chromosomes. For example, Prader-Willi syndrome occurs when certain genes on chromosome 15 of the paternal chromosome are unexpressed or silenced.

Recent studies are attempting to take advantage of the reversible trait of epigenetics in treating cancer patients. Already, certain patients suffering from liver cancer respond favorably to drugs that inhibit DNA methylation.

As evidence that individualized gene expression is, in fact, real, twin studies provide a basis for epigenetic claims. Identical twins carry all the same genes, but they are by no means exactly the same. Whether due environmental or epigenetic effects, twins might respond to the same stimuli in different ways. A study by King’s College London found that identical twins possessed differing pain tolerances. In addition to studying the epigenetic differences between the twins, researchers examined the epigenetic similarities among unrelated subjects. Further epigenetic studies in this realm might better target pain sensitivity with a focus on epigenetic modification.

Epigenetics is not only the basis for the fundamental differences that make us unique, but could be the answer to an effective treatment for common diseases and disorders.

References:

Raddihough, G., & Zahn, L.M. (2010). What is Epigenetics? Science 330(6004): 611.

King’s College London. “Pain sensitivity may be influenced by lifestyle, environment, twin study suggests.” ScienceDaily. ScienceDaily, 4 February 2014. <www.sciencedaily.com/releases/2014/02/140204112123.htm>.

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What does your anterior insula tell you about love?

by Rebecca Steinberg

Love and lust. Devotion and desire. No matter how it’s phrased, perceptions of love and lust run hand in hand.

The present clinical study by Cacioppo et al. (2013) reinforces the assumed distinction between anterior and posterior insula regions in expressing feelings of love and lust, respectively (Cacioppo et al., 2012; Cacioppo & Cacioppo, 2013). In a patient with an anterior insula lesion, feelings of love were delayed more than feelings of lust. However, this is not to say that feelings of love weren’t present. The anterior insula may be important for the contribution of feelings of love, but is not its sole determinant.

The rationale behind the regional separation of the insula is that love is a more abstract reaction, and is therefore located in closer proximity to the parietal lobe; whereas lust is a more concrete emotion, and is therefore located in closer proximity to sensorimotor regions of the brain. The anterior insula appears to be associated with not only the concept of love, but of abstract emotional processing.

Given the findings of this study, why do humans so often associate love and lust? One possibility is that closely associated pathways are activated when either emotion is evoked. Both love and lust activate reward pathways with regards to relationships. Another possibility is that there exists a societal influence which dictates that sexual desire complement feelings of love.

However, if the latter were true, how might individuals with little sentiment to sexual satisfaction be assessed? When an individual places minimal emotional value on sexual relationships, is their neutrality a biological or social discrepancy? A point of further study might be to compare the insula regions of individuals who place greater emphasis on lust than love, those who place equal emphasis on both emotions, and those who are hopeless romantics.

On a similar note, how might the anterior and posterior insula regions differ among age groups? Does the anterior insula develop with age or experience? As we grow older, we tend to seek out lasting relationships rather than temporal affairs. One reason for this might be the circumstances we are faced with. As older individuals, we are more likely to seek out love rather than the instant gratification of lust. Future neuroimaging might compare the insular cortices of high school sweethearts to old married couples.

The study by Cacioppo et al. (2013) provides a launching point for future studies involving the expression of love and lust. The significant contribution of the anterior insula to feelings of love suggests that emotional reaction may be specific to certain regions of the brain.

  References:

Cacioppo, S., & Cacioppo, J.T. (2013). Lust for life. Scientific American Mind, 24 (5), 56-63.

  Cacioppo, S., Bianchi-Demicheli, F., Frum, C., Pfaus, J., Lewis, J.W. (2012). The common neural bases between sexual desire and love: a multilevel kernel density fMRI analysis Journal of Sexual Medicine, February. doi: 10.1111/j.1743-6109.2012.02651.x. 

  Cacioppo S., Couto B., Bolmont M., Sedeno L., Frum C., Lewis, J. W., Manes F., Ibanez  A., & Cacioppo, J. T. (2013) Selective decision-making deficit in love following damage to the anterior insula. Current Trends in Neurology. 7, 15-19.

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Lather, Rinse, Repeat: How Sleep Cleanses the Brain

by Rebecca Steinberg

If I told you that your brain is similar to a machine, your first thought might be about the electrical potentials that travel along axons or the chemical signals generated at synapses.  But what if I told you that your brain is like a machine—not because of the way it sends signals—but because it requires regular maintenance?

Emily Underwood considers the role of sleep based on a new study from the University of Rochester.  For years, researchers have been debating and proposing theories for the necessity of sleep.  Why would humans sacrifice constant alertness for a state of unconsciousness?  Maiken Nedergaard, Lulu Xie, and their colleagues may have justified the purpose of sleep.

According to the study, in sleep, the brain cleans itself.  Specifically, cells within the brain channel fluids in order to clear the brain of toxic metabolic byproducts.  The fluid, cerebrospinal fluid (CSF), acts as a scrub that washes away the “dirt” outside of cells.

Xie studied the activity of these channels in sleep for mice and found that the channels expanded to allow for more CSF to flow into the brain in sleep, but not when the subject was awake.  The theory behind this is simple: the brain cannot be “in use” and “in repair” at the same time.

Nedergaard et al. suggest that the “dirt” washed away includes byproducts from usage.  If these byproducts build up, Nedergaard predicts, this might be a cause of general brain damage and common neurological diseases through aggregation, such as Alzheimer’s disease.  This serves as a potential two-way street—these byproducts may signal to our brain that we need sleep, perhaps making us drowsy.

Other vying theories on sleep include memory consolidation, metabolism calibration, and fortification of the immune system.  Many researchers believe that these tasks work hand-in-hand during sleep, and that not just one mechanism is the primary function of sleep.  We already know that individuals who sleep alone are prone to a sleep fragmentation and fatigue during the day (see last month’s blog).  Now, we can predict that the cause of this fatigue is the buildup of metabolic byproducts, or the inability for the brain to give itself a good scrubbing.

Though there is still much to understand about sleep as a physiological requirement, the findings of Nedergaard et al. pave the way for further studies in the field.  Is this finding concerning CSF channels applicable to humans, or is this just observable in mice?  Can the activation of these channels be manipulated to remedy neurological diseases?  Do drugs, such as caffeine, that stimulate the brain to combat sleep have any effect on these channels?  Researchers have just scratched the surface of the common but mystifying phenomenon of sleep in humans.

  References:

  Underwood, E. (October 17, 2013). Sleep: The Ultimate Brainwasher? Science/AAAS, 342(6156), 301. http://news.sciencemag.org/brain-behavior/2013/10/sleep-ultimate-brainwasher

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Avoiding Loneliness: Deciding between Healthy and Hermit Lifestyles

by Rebecca Steinberg

The next time you see someone standing alone at a party, try to strike up a conversation. You may be extending both of your life expectancies—a total “win-win.” The biological mechanisms underlying the act of socializing may lead to a healthier, longer life compared to that of isolated individuals. CCSN Director, John Cacioppo, recently presented a TEDxTalk about the “Lethality of Loneliness,” reviewing evidence that the more socially isolated an individual feels, the more likely they will shorten their lifespan due to the activation of various biological warning mechanisms. 

As a species, the human race stands apart from other social animals in the sheer complexity of our communicative interactions. Though other animals run in packs and depend on one another for survival, no other species values a society more rich with the unique relationships and fundamental principles that humans possess for one another.

Cacioppo notes that humans gain independence through adulthood, but cannot fully thrive in a truly solitary life. Attempting to master the advanced social structures we possess is crucial to how humans perceive one another. As Cacioppo remarks, being an adult in a social species often means being the one on whom others can depend. 

This is evident in the way society marks the qualities of a good versus evil character. When considering a good individual, we imagine someone selfless, who is willing to go out of his or her way for the wellbeing of others. An evil individual is defined as someone self-inclined, performing deeds at the expense of others.

At the root of our being, we feel a sense of discomfort when confronted with an isolating experience. Loneliness is a highly aversive state—a biological signal warning us of threats or damage to our social body. Despite the fact that loneliness is associated with an aversive reaction that is designed to motivate us to care for our social body, the prevalence of lonesomeness is on the rise. Why?

Cacioppo suggests that stigma associated with loneliness prevents people from discussing their loneliness candidly, but in fact a lonelier brain makes an individual more prone to both complex and fundamental behavioral changes. As Cacioppo notes, it is dangerous on the social perimeter, and our brains have evolved to go into a self-preservation mode. For instance, when a person feels lonely, the portions of the brain related to attention are more active than those dedicated to empathy in response to a negative social image. This suggests that an individual who is lonelier tends to be more focused on self-preservation than the condition of others.

In addition, an isolated individual increases their implicit hyper vigilance for social threats, which can leave them defensive and more focused excessively on their own welfare even at the expense of others. When an individual is isolated, they both seek out social contact and assume defensive behavior, increasing the likelihood of negative social interactions and increasing negative biological mechanisms, such as stress. These responses promote survival in hostile social environments but can make it more difficult to escape the grips of loneliness in affine social environments.

Cacioppo points out that even at night, when one is supposedly most relaxed, the brains of people who feel lonely remain on high alert.  As a result, they show more sleep fragmentation and microawakenings, leaving them more fatigued during the day. Feelings of loneliness have even been found to influence the expression of certain genes, and it is certain that specific behaviors reveal themselves in response to environmental stimuli. In response to an isolating situation, executive functioning is diminished and behaviors are inclined toward self-preservation and worry.

How do we cure the negative health effects of loneliness? Although the answer is not simple, it begins with reaching out and sharing good times with others. We might reach out to our family, friends, or community. Reconnect with lost connections, perhaps volunteer for activities that you enjoy, and become a part of something greater than yourself. In a society where time is the commodity we value most, a small time sacrifice now could lead to added years of thriving, surviving, and getting connected.

  References:

Cacioppo, J. T., (2013, September 9). The lethality of loneliness: John Cacioppo at TEDxDesMoines.  [Video File]. Retrieved from http://www.youtube.com/watch?v=_0hxl03JoA0. 

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Connecting the Dots with functional connectivity MRI

by Rebecca Steinberg

When we perform an action, such as raising a glass of water, we recognize that several cognitive actions are at play. We must visualize the glass, perceive its location, and then maneuver our arm in the orientation to best grasp the object. It has been firmly established in our scientific understanding of proprioception and our interactions with our environment that there must exist some cognitive connectivity leading to holistic movement.

But how can we best make these connections evident? One tool many scientists have depended on is fcMRI, or functional connectivity magnetic resonance imaging. The rationale behind this method is simple. Different regions of the brain are presumed “connected” when they appear active in response to a given stimulus. However, a recent review by Buckner et al. suggests that the data gathered from fcMRI may not serve as sound evidence for the broad claims they endorse.

Cases in which a portion of the brain is damaged or not present demonstrate that the entire brain does not need to be intact to perform specific functions. While this suggests that specific pathways do exist within the brain leading to function, is there a possibility that tissues can heal or compensate for missing connections through the generation of new pathways? fcMRI does not account for or readily show the unknown, multiple pathways dedicated to the same function.

Similarly, when examining fcMRI results, Buckner et al. point out the apparent effects of individual experience and personal development on brain activity. Subjects may respond in different manners to the same stimulus. Even when tested at rest, when it appears all human minds would possess similar brain activity, certain individualistic elements, such as head motion and proneness to anxiety, may lead to deceiving observed brain activity trends.

fcMRI raises more questions for researchers examining brain connectivity. Though it is convenient to identify “regions” of the brain, fcMRI begs the question of whether these areas of activity exist, or if they are more likely bundles of individual pathways that follow a coincidental route in the brain. Beckner, et al. suggest that fcMRI should not be a tool used to generate answers, but to propose new questions concerning connectivity.

However, many findings have been brought to the attention of researchers by fcMRI. The ability to examine activity across the entire brain as opposed to a small portion has led researchers to recognize that certain locations in the brain do in fact activate in response to a stimulus, though the methods behind this observation are still mystifying.

At the same time, the relations between these apparent networks are highlighted through imaging in a way previously unavailable. By examining the presence of “anticorrelation” between brain connections, opposing pathways are activated to either undergo or avoid a response to stimuli. Despite these significant cognitive findings, alternative methods are required to elucidate this data.

Because of the potential pitfalls fcMRI is subject to, Buckner et al. suggest that rather than using fcMRI as evidence for proposed connective theory, the imaging technique instead be used as a launching point for further research, to be justified by more comprehensive means. fcMRI might serve as an incredible tool to bring attention to cognitive pathways previously unknown, but extensive research and alternative methods are required to fully accept any related connectivity theories.

References:

Buckner, R. L., Krienen, F. M., and Yeo, B. T. T. (2013). Opportunities and limitations of intrinsic functional connectivity MRI. Nature Nueroscience 16(7): 832-837.

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Is Heartbreak All In Your Head?

by Rebecca Steinberg

Being ostracized can cause a person great anxiety.  We often describe feelings of social and romantic rejection in parallel with physical pain, hence the term “heartbreak.”  But are these pangs of pain in response to distress directly associated with rejection, or do these perceived physical responses operate on a much deeper neurological level?

Several studies with small number of subjects highlight the activation of the pain matrix in the brain in response to social rejection. Qualitative reviews of Cyberball neuroimaging studies in particular emphasize the pain matrix activated by ostracism in a three-person game of catch with strangers.  These studies argue that activity of this region directly corresponds to the manifestation of social pain in the body.

However, a recent, quantitative meta-analysis of the Cyberball neuroimaging studies challenge this view by arguing that depending on the type of rejection, different regions of the brain may be stimulated, and that even with the stimulation of the pain matrix, there may be no physical connection between emotional rejection and literal pain.

Director of the CCSN HPEN laboratory, Stephanie Cacioppo et al. investigated this question through a quantitative meta-analysis of fMRI studies of social rejection including more than 300 participants.  Their findings indicate insufficient evidence exists that social rejection manifests itself in a literal, physical form.  Even with the manipulation of individuals involved in rejection, from friends to romantic partners, deficient neurological imaging data was available to comfortably conclude the connection of literal pain with rejection.

This work leaves open a number of important questions.  How heavily activated are certain regions of the brain when an individual is more or less concerned with the rejection at hand?  Could other types of rejection, such as from programs, institutions, or friendships, activate different brain regions than the rejections of strangers or romantic partners?  And finally, if the pain centers of the brain are activated and indeed incite physical pain in an individual, what motivates a person to keep moving forward emotionally in their attempts for approval, despite the natural human tendency to avoid painful stimuli?  The study by Cacioppo et al. reveals that there is much to be understood in the connection of emotional events and their accompanying physical response.

References:

Cacioppo, S., Frum, C., Asp, E., Weiss, R. M., Lewis, J. W., & Cacioppo, J. T. (2013). A Quantitative Meta-Analysis of Functional Imaging Studies of Social Rejection. Sci. Rep. 3, 2027; DOI:10.1038/srep02027.

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Successful Searches for On-line Sweethearts

by Rebecca Steinberg

The “high-school sweetheart” image of dating that America is known for is undergoing rapid technological upgrades.  With the emergence of on-line dating, meeting other singles is a convenient click away.  On-line dating has become an innovative socializing resource, particularly for those with full work weeks and little time.  Though the means of online dating has become diverse and expansive, the outcome of marriages founded through dating sites has not been as extensively investigated.  John Cacioppo, director of the CCSN, et al. reveal the effect of spouse meeting venue, on-line or otherwise, on overall marital satisfaction.

The data suggests that marriages generated from an on-line venue are more likely to result in marital satisfaction than off-line venues.  What might cause the effectiveness of on-line dating?  Cacioppo et al.’s study didn’t specifically address this question. Further scientific studies need to be done to explore the causal relationship between meeting venues and long-term marital satisfaction. In the meantime, one might draw a few hypotheses.

Three factors of dating spring to mind that might account for this trend.  The first and most obvious reason for the success of on-line dating is the ability to be selective for traits.  When an individual knows the type of partner right for them, easily selecting those traits and narrowing available options proves to be more time-efficient by leaving less room for unexpected, incompatible qualities.  While traditional daters might have to engage in scores of incompatible matches, on-line dating provides more guaranteed matches by emphasizing personality before physical attraction.

The second reason might be the lack of face-to-face confrontation.  As observed in myriad social media sites, such as Facebook, Tumblr, and Twitter, the ability to converse with others is made easier through a computer, rather than a personal interaction.  On-line dating draws away the pressure of being “interesting” on the spot by generating user confidence.  By lowering social pressure, dating sites appear to generate more fluid conversation in which each partner is eager and interested in what the other is typing.  This greater “on-line self-disclosure” may take away the tension and uncertainty that typical dating methods might possess. 

The third reason for the success of on-line dating may be the personality type of site users.  Users may be more impulsive or willing to take risks on-line rather than off-line, because the consequences of “putting oneself out there” appear less severe.  In addition, users may be specifically looking for marriage partners, rather than casual dating, and so might take on-line dating more seriously than off-line couples.  Motivation, willingness, and overall lifestyle may be driving forces behind the success of on-line founded marriages.

Despite the apparent success of online dating, on-line venues may still be improved to accommodate even more searching singles.  By examining which off-line venues appear the most successful for marriage (schools, places of worship, and social gatherings) in contrast with the least successful (bars, work, and blind dates), dating sites may be restructured to provide an even more satisfactory dating experience for those too busy to fit dating into their schedule. 

References:

Cacioppo, J. T., Cacioppo, S., Gonzaga, G. C., Ogburn, E. L., & VanderWeele, T. J. (2013). Marital satisfaction and break-ups differ across on-line and off-line meeting venues. PNAS, 110 (25), 10135-10140.

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Debating the Dependability of Neuroscience

by Rebecca Steinberg

Evidenced by its booming popularity, neuroscience is an alluring area of study.  Explored theories and research have expanded the scope of the field, and the improved ability to analyze large quantities of data has led neuroscience through rapid growth over the past few decades.  However, as experiments become more refined and general ideas flourish with detail, increasing concern over the reliability of statistical observations has caught the attention of researchers.

Potentially one of the greatest weaknesses of current statistical data is the dependence on small sample size to support an observed phenomenon.  A significant amount of neuroscience research depends on the analysis of cognitive anomalies.  Because of the rarity of these conditions, the dataset that researchers have at hand is minimal.  If the sample size of an experiment proves to be too small, can the conclusions drawn be reliably “true?”  If the published results of an experiment are flawed, how will future experiments affiliated with unreliable data be affected?  Button et al. (2013) examine the low power of small sample size through two lenses: biased research and unbiased research.

In biased experimentation, the intentional manipulation of low power data, often due to publishing incentives, has dramatic effects on the reported results.  Because of the small sample size, every observation is noticeably significant in data analysis.  Selective exclusion or inclusion of data, even in small quantities, would have a greater effect on reported phenomena.  This subtle manipulation of low powered data generates significant problems for the literature as well as numerous ethical uncertainties for future studies.

In unbiased experimentation, there exist innate problems related to low statistical power.  The very nature of using low powered data often leads to overestimation of the magnitude of an effect.  The difficulty in using low powered data is determining the cutoff for which data is deemed a true effect or a false positive.  The overestimation of effect size might also create problems for future replication studies by skewing the expected results.

The prominence of low statistical power currently existing in the literature was analyzed in animal model studies and neuroimaging studies.  According to Button et al., the statistical power ranged from 8 to 31 percent—an alarmingly low rate for research crucial to the understanding of modern neuroscience.  With the apparent scarcity of examinable data, how can conclusions drawn from these studies reliably supply true information?

Button et al. offer an almost impeccable strategy to avoiding bias and the negative effects of low statistical power.  By employing more uniform methods of reporting results and procedures as well as improved accountability among researchers through meta-analysis, the probability of flawed data in the neuroscience literature might begin to dissipate and generate dependable, replicable results.  Though small sample size may still exist for individual experiments, the accountability by other experiments improves the likelihood that observed phenomenon consists of true effects.

  References: 

Button, K. S., Ioannidis, J. P. A., Mokrysz, C., Nosek, B. A., Flint, J., Robinson, E. S. J., & Munafò, M. R. (2013). Power failure: why small sample size undermines the reliability of neuroscience. Nature, 14, 365-376.

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Can an Image Justify a Theory? Weighing the Usefulness of fMRI

by Rebecca Steinberg

Functional magnetic resonance imaging (fMRI) provides a safe method of observing brain activity in a spatial and temporal context.  Although its recent use primarily classifies brain activity and localization, it is only logical that neuroimaging be used as a supplemental tool for integrating a variety of existing cognitive theory.  For example, fMRI studies reveal that an aging mind declines in certain activity, such as processing speed, but compensates by more heavily activating regions corresponding to task-relevance.  The ability to visualize regional stimulation of the brain in response to assorted stimuli strongly correlate with the theory that mechanisms underlying observed thoughts and behaviors are more established in certain parts of the brain and less so in others.  The big question on everyone’s mind is what strategy to take in conclusively explaining behavioral response using the information gleaned from neuroimaging.

Mather, Cacioppo, & Kanwisher suggest that neuroimaging can refine and contribute to cognitive theory beyond localization through four fundamental questions.  The first question concerns whether a specified mental process is associated with a localized mechanism in the brain.  The second examines whether these mechanisms are activated by a given task and might be used as markers for specific functions.  The third question serves to reveal the depth of boundaries between different stimuli and tasks.  The final question assesses to what extent two distinct tasks engage similar mechanisms of the brain.  The focus of these questions is not solely on “where” the brain is stimulated, but when the regions are active and in response to what stimuli.

fMRI can be used to shed light on established cognitive theories not through direct comparison of images to behavior, but through the interpretation of what these images might mean on a behavioral level.  The four questions proposed by Mather et al. take a step-by-step approach to connecting observed brain activity in fMRIs to generally observed behavior in mankind.

References:

  Mather, M., Cacioppo, J. T., & Kanwisher, N. (2013). How fMRI can inform cognitive theories. Perspectives on Psychological Science, 8(1), 108-113.

  Mather, M., Cacioppo, J. T., & Kanwisher, N. (2013). Introduction to the Special Section: 20 years of fMRI – what has it done for understanding cognition? Perspectives on Psychological Science, 8(1), 41-43.

John T. Cacioppo is the director of the Center for Cognitive and Social Neuroscience at the University of Chicago.

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