Research blogging

I have been participating in the Bloggers for Peer-Reviewed Research Reporting (BPR3) initiative, which attempts to highlight serious, thoughtful blog entries on peer-reviewed research (using icons). The aggregation system I mentioned before has now gone live on the great site Researchblogging.org. Basically, whenever a blog author wants to make use of the new system, they go to the Researchblogging site, enter citation meta-data into a form which then spits out code that gets included in the relevant blog entry. Then Researchblogging.org aggregates all the blog entries that contain the code, lists them on the website and categorizes them into subject-areas.

Have a look at the site, it's a fantastic way to discover more academic blogs and entries on serious research.

Your brain on politics: the bad and the better

The bad

A disturbingly bad article, entitled "This is Your Brain on Politics", appeared recently in the New York Times. It presented purported "research" about the brains of swing voters in the 2008 US Presidential Elections but, unfortunately, the article does little but illustrate the dangers of circumventing the peer-review process and the shocking state of science journalism in the mainstream media. Luckily, the NYT published an angry letter by a group of cognitive neuroscientists condemning the article and the blogosphere responded forcefully, among the blogs that attacked the piece were: Bad Science, Neurocritic, Mindhacks, Brainethics and Natural Rationality. Subsequently, Nature published an editorial also condemning the article and even Slate joined in.

The better

Thankfully there has also been some better recent research concerning 'the brain on politics' and good media coverage thereof to boot. The subject of last week's edition of ABC Radio National's fantastic radio show/podcast, All in the Mind, was "The Political Brain" and the show discussed, among other things, an interesting study in Nature Neuroscience entitled "Neurocognitive correlates of liberalism and conservatism" (see also the supplementary materials). The study, led by NYU assistant professor of psychology David Amodio, evoked considerable interest and was widely discussed by the science blogging community. (See links below). I suspect the study has been somewhat misunderstood, so, despite it being stale by web standards, I'll look at it in some detail.

The hypothesis the authors defend is that political orientation (conservative vs. liberal) is "associated with individual differences in a basic neurocognitive mechanism involved broadly in self-regulation" (Amodio et. al., 2007: 1246). They go about testing this proposition in a somewhat tortuous way: previous research had shown that conservatives are "more structured and persistent in their judgments and approaches to decision-making" whereas liberals "report higher tolerance of ambiguity and complexity, and greater openness to new experiences". Other research showed that psychological differences between liberals and conservatives "map onto the... self-regulatory process of conflict monitoring" (the system that detects a mismatch between habitual responses and the response required in the current situation) which in turn has been "associated with neurocognitive activity in the anterior cingulate cortext"(ACC). So, to test whether liberals and conservatives differ in their patterns of self-regulation, the authors measured the acitivity of the ACC in a situation requiring conflict-monitoring.

Amodio et. al. conducted this test by using an electroencephalogram to record the ACC activity in 43 subjects who were asked to complete a go/no-go association task (Nosek & Banaji, 2001). For the task, participants were placed in a sound-proof room, in front of a computer screen in the center of which either an "M" or a "W" appeared. Half the subjects were instructed to "go" (i.e. hit a key) when they saw an "M" and do nothing ("no-go") when they saw a "W", while the other half were asked to do the opposite. The task consisted of 500 trails, 80% of which consisted of the "go" stimulus and 20% of the "no-go" stimulus. This meant that for half the subjects "M" became a habitual response (which needed to be inhibited when they saw a "W") and for the other half "W" became habitual (which needed to be inhibited when they saw an "M"). Additionally, before the task was administered, subjects reported their political attitudes confidentially on a scale ranging from -5 (very liberal) to +5 (very conservative).

The results were very suggestive. Firstly, however, it is important to note that there are in fact two types of finding in this study: the behavioral findings (which the authors do not focus on) and the cognitive neuroscience findings (which the authors emphasized and most of the subsequent discussion revolved around). The behavioral finding - which is interesting all by itself - is that liberals were more accurate than conservatives on the no-go trails (r(41) = 0.30, P less than 0.05) which "suggests that a more conservative orientation is related to greater persistence in a habitual response pattern, despite signals that this response pattern should change".

The neurocognitive findings were (among other things) that the response-locked error-related negativity (ERN) - a measure of conflict between a habitual tendency and an alternative - was strongly correlated (r(41) = 0.59, P less than 0.001) with political attitudes:

Additionally, liberalism was strongly associated with greater conflict-related neural activity when a habitual response had to be inhibited:

Subsequently, localization analysis was performed, which confirmed that the above mentioned ERN activity originated from the ACC. Amodio et. al. conclude that "taken together, our results are consistent with the view that political orientation, in part, reflects individual differences in the functioning of a general mechanisms related to cognitive control and self regulation".

A couple of observations. The study is clearly preliminary and a good deal of the reporting of it in the lay press went far beyond the evidence. The authors, however, obviously cannot be blamed for this - they were careful not to stray from the evidence in their paper. Furthermore, only 43 subjects took part in the study and, worse, only 7 of those self-reported as conservative. The findings would have to be replicated by a different team in a different part in the US with a larger number of participants before too much stock can be placed in them. For now this can be filed under "interesting and suggestive but preliminary". We'll have to wait and see how the literature develops.

Links

• Coverage of the Amodio paper on other blogs: NeuroLogica, Cognitive Daily, Natural Rationality, Crooked Timber, Mixing Memory, and Neurocritic.
• News coverage: Scientific American.
  

Bibliography

Amodio, D.A., Jost, J.T., Master, S.L., Yee, C.M. (2007). Neurocognitive correlates of liberalism and conservatism. Nature Neuroscience, 10, 1246-1247. DOI: 10.1038/nn1979

Nosek, B. A., & Banaji, M. R. (2001) "The go/no-go association task," Social Cognition, 19(6): 161-176.

Blogging about peer-reviewed research

Some of you might have noticed that in my post about the recent BMJ article about active parents raising active children I started using BPR3's icons indicating which of my posts are about peer-reviewed research. The icons (which can be seen here) are designed to draw attention to thoughtful, serious blog posts on papers that have been published in journals reviewed by relevant experts. (See BPR3's guideline for more information). An upcoming feature - which I hope to participate in soon - will aggregate all blog posts using the icons at a central location on the BPR3 website, which in turn will draw more attention to quality science blogs. (Something I sure hope this blog counts as a token of...).

Peer-reviewed nonsense: Active Parents Raise Active Children

The British Medical Journal - which is highly respected and has the 6th highest impact factor of all general medical journals - has just published an almost entirely worthless study on the effect of parental physical activity on the physical activity of their 11-12 year old children (Mattocks et. al., 2007). The study is worthless, in short, because it proceeds as if the entire field of behavioral genetics does not exist; the authors simply assume their conclusions are not confounded by genetic factors. It astonishes me that such fatally flawed article can get past peer-review in such a prestigious journal. That such an obvious confound as genetics can be overlooked is a testament to the continuing detrimental effect of the blank slate on modern science (Pinker, 2002).

First a bit more about the study itself. The authors used data from the Avon longitudinal study of parents and children, which collected (and is continuing to collect) a wealth of data from 14,061 families. The specific question addressed was which factors in the child's early life (defined as before age 5) influenced the objectively measured physical activity of the same children at ages 11-12. The authors collected the physical activity data with uniaxial actigraph accelerometers from 5,451 11-12 year old children in the Avon cohort and then looked at data collected when the children were aged 5 or younger for causal variables. In other words, the researchers wanted to know which early life variables predicted physical activity at age 11-12. The conclusion of the research was:

We have shown that children are slightly more active if their parents are active early in the child’s life. This suggests that encouraging physical activity in parents may also influence their children to become more active, with the added advantage that physically active parents are healthier (Mattocks et. al., 2007: 7).

So, in other words, active parents socialize their children to be active themselves. (It's clear the authors are thinking in terms of socialization, something the following quotation perhaps illustrates a bit better: "in our study, maternal activity during pregnancy... was positively associated with physical activity in the children. It is unlikely that this is due to biological factors in utero but is more likely that physical activity during pregnancy is a marker for later maternal physical activity and that this in turn influences children’s physical activity" [Mattocks et. al., 2007: 6].)

A slight problem...

Children share 50% of their genes with each parent, and since all human behavioral traits are heritable (the so-called First Law of Behavioral Genetics, Turkheimer, 2000), genetic factors are always possible confounds when relating parenting style (or other parental behavior) to outcomes in the children. As Turkheimer explains:

It is no longer possible to interpret correlations among biologically related family members as prima facie evidence of sociocultral causal mechanisms. If the children of depressed mothers grow up to be depressed themselves, it does not necessarily demonstrate that being raised by a depressed mother is itself depressing. The children might have grown up equally depressed if they had been adopted and raised by different mothers, under the influence of their biological mother's genes (2000: 162).

The exact same problem holds for the Mattocks study: one can't simply assume parental physical activity (or lack thereof) influences children to be active (or inactive) because it's possible that sedentary children inherit sedentary genes from their sedentary parents and active children inherit active genes from their active parents. Or, to put it differently, the fact that the physical activity of parents when the children were young is correlated with the children's degree of activeness later on simply does not constitute evidence of a socialization effect.

To be clear, I'm not claiming children are not socialized in this way; my point is we cannot tell one way or the other from the data presented because it fails to distinguish between the relevant causal hypotheses. I really hope I've somehow been daft by missing how the authors controlled for genetic factors. The alternative is that a leading medical journal published an article that is scientifically illiterate, that overlooks obvious possible confounds and that is thus worthless in terms of deciding what causes 11-12 year old children's degree of physical acitivity. Frankly, that I've made a mistake is far more palatable to me.

(See also: ScienceDaily's report on this research).

Bibliography

Mattocks, C., Ness, A., Deere, K., Tilling, K., Leary, S., Blair, S.N., Riddoch, C. (2007). Early life determinants of physical activity in 11 to 12 year olds: cohort study. BMJ (British Medical Journal). DOI: 10.1136/bmj.39385.443565.BE

Turkheimer, E. (2000) "Three Laws of Behavior Genetics and What They Mean," Current Directions in Psychological Science, 9(5): 160-164.

Pinker, S. (2002) The Blank Slate: The Modern Denial of Human Nature (London: Penguin).