Friday, July 23, 2010

Cognitive Dissonance: Not Just for the Layperson

I must admit, I had not carefully read Dr. Campbell's "last word" from the "discussion" of his reply to Denise Minger. His refusal to engage in discussion told me everything I needed to know. But in spelunking around for something else on that page, I came across this quote:

I had hoped to have had a civil discourse, but this is difficult when the questions come from uncivil people. I also don’t have time to answer superficial questions of others like ‘what is the detailed mechanism of protein induction of high cholesterol levels’ – that easily could become an entire but relatively useless dissertation when the “mechanism” most decidedly is a symphony of mechanisms, as I explained in our book. At this point, the far more important observation is the dramatic increase in serum cholesterol.

Hmmm, I wonder what Campbell's definition of "uncivil" is? Seems to have some conceptual overlap with the second sentence, i.e. those who ask "superficial" questions are being "uncivil". The question in question came from me, and I'm glad to see it had one of the desired effect. My preferred outcome would have been that Dr. Campbell actually answered the question. Then I would have learned something. It is unfortunate that he instead evaded the question as above, because then all we learn is that a) he doesn't have an answer, but b) thinks he does, and is thrown into painful cognitive dissonance when confronted by the truth of his ignorance. The nonsense about there being a "symphony of mechanisms" is, I believe, a subtle trick played on Dr. Campbell by his own mind. There are indeed many possible causes, and may be several interacting processes. But he confuses "I don't know which of the many possibilities contributes to the effect" with "here is what we know, a complex process". Classic mental band-aid for cognitive dissonance.

Anyway, I think my goal has been accomplished. I wanted to know if Dr. Campbell had any relevant information. If not, I wanted him to publicly torpedo his own credibility. Mission accomplished. Next time he wants to show up and bash a low-carb or paleo book an Amazon, you have ample material to demonstrate his irrationality.

Thursday, July 22, 2010

What T. Colin Campbell Didn't Want You to See

T. Colin Campbell has chosen to not participate in any discussion of his own "scientific results". Take a look at his last word on the topic, note metadiscussion of what "science is about" rather than actually discussing any science, and check the shoes.

The great thing about the Internet, of course, is that it is impossible to censor anything. I'm pasting the comments I submitted to Campbell's site below. These were not approved. Compare with the openness displayed by Denise Minger in publishing comments from all comers, and fostering open discussion. Draw your own conclusions. If you have submitted comments to that were not published, feel free to post them in the comments here. I'll send through anything that isn't overt spam.

To be fair, these comments may yet show up. There is a perfectly acceptable explanation that they haven't been published yet. I'm sure most bloggers have experienced "falling behind in comment moderation". If these comments are published, I partly retract my criticism. But the main portion remains valid: exchange of information is crucial to scientific progress. If you're not willing to exchange information, you're not interested in scientific progress.

I posted this just because it seemed odd to be revising such a benign comment. Who does this, and why?

Uh, why did your answer to my original question change from ““Dr. Campbell said he will be able to post comments now and then, although he cannot respond to every question.” to “Dr. Campbell said he will participate to the extent possible.”? Those seem like they say the same thing to me.

At any rate, I expect Dr. Campbell will find it a better use of his time to respond to specific points here rather than having to write lengthy detailed work such as above.

Here's a harder question:

From the response above:

“First and foremost, our extensive work on the biochemical fundamentals of the casein effect on experimental cancer in laboratory animals (only partly described in our book) was prominent because these findings led to my suggestion of fundamental principles and concepts that apply to the broader effects of nutrition on cancer development.”

Can you explain what these fundamental principles might be, or at least direct me to a detailed discussion? Proteins are broken down in to amino acids in the gut (at least in healthy individuals). These amino acids are then transported throughout the body, where they may be used to build new proteins. How does a specific mixture of amino acids trigger cancer growth? And of course I doubt most free-living organisms eat large quantities of isolated casein. So if I eat a meal containing casein, the mixture of amino acids absorbed reflects that off the total protein content of the meal, not just the casein.

It seems that in order for casein to have a specific role, it would need to trigger some other biological response beyond it’s simple amino acid content. For example, we know that most cancers have a very high glucose requirement, as they largely rely on anaerobic glucose metabolism for energy. We might then expect insulin to be required to stimulate glucose transport. Some cancers do indeed show higher expression of insulin receptors, see e.g.

From this we might hypothesize that dietary carbohydrates would drive cancer growth by providing both a supply a glucose and increased insulin secretion. It further can encompass other observations, e.g. the association of dietary fat and cancer. When eaten in combination with carbohydrate, fat will amplify insulin secretion.

Returning to your hypothesis that casein has a unique potential to stimulate cancer growth. What metabolic pathways are followed that create the “casein effect”? Is there some specific hormonal signal uniquely stimulated by casein?

And a link to a multivariate analysis that would answer at least some of Dr. Campbell's objections:

Here is an interesting blog on a multivariate analysis of China Study data:

I put these comments under the post "The Challenge of Telling the Truth:


Your suggestion about keeping an “open attitude” is a good one. However, you need to keep an open attitude about scientific evidence as well. The way you talk about “truth of health” sounds a lot more like religion than science. Perhaps this is simply a communication gap. I sincerely hope that you and your father have the sort of open and inquisitive minds required for scientific progress. There is no absolute “truth” in science, as this would imply we have perfect information. I doubt even the staunchest supporter of any dietary dogma would claim that we have perfect understanding of the deep complexities of human biology.

I will reiterate here what I have said elsewhere: scientific progress is about two-way communication. You and your father likely have information that supports your hypotheses, information that others do not have. However, I’m sure you’d agree that others have information that you do not as well. The only way to reach “agreement” is communication, so we’re all on the same page. This is why dialog is so fundamental to scientific progress. I hope you and your father will participate in this dialog.


“Despite lacking an adequate understanding of statistics and causality, this person used her intelligence and writing skills to compose a critique that might seem persuasive to laypeople.”

You might wish to expand on this a bit. It sounds like you’re saying she is both stupid (“lacking…understanding”) and intelligent in the same sentence. And I’m sure you would agree that “laypeople” need to have greater understanding of the issues so that they can make informed decisions, rather than simply picking an “expert” to blindly follow. Perhaps you can provide a little Statistics 101 discussion for us to better illustrate the shortcomings in Ms. Minger’s analysis for the lay public?

Yes, We Have No Bananas

Just a very quick post. It's been almost a week since I submitted my registration for Prolific commenter "durianrider" is one of the principles at this site. You can read some of his "insightful" comments on the last post. Note, however, the one question I asked repeatedly, to which he gives no attention. Not only do I think I will never get approved to post on, I doubt I'll even get a reason. Draw your own conclusions.

Another interesting development is the new(ish) web site Dr. Campbell's response to Denise Minger's critique is featured prominently, and better yet, Dr. Campbell has indicated that he may participate in some discussion here. I've posted a few questions, and urge others to do the same. I recommend you focus the discussion on scientific topics, as opposed to his opinion of Denise Minger, etc. Come armed with some hard questions on the connections between nutrition and metabolism, particular as they relate to Dr. Campbell's hypotheses. I believe this exercise has two realistic outcomes: either Dr. Campbell has some answers (which actually would be very cool), or he stonewalls. Either way we learn something interesting.

*** UPDATE ***
Well, it didn't take long for us to learn something interesting. From the comments on Dr. Campbell's reply to Denise Minger:

Based on the response received thus far, we have determined that our prior idea of a reasoned and civil discourse, with participation by Dr. Campbell, is not feasible and have decided to discontinue this discussion thread. Before closing, however, Dr. Campbell wanted to respond to comments from Denise Minger. Her comments are posted above, and Dr. Campbell’s response follows.

In other words, Dr. Campbell is going to have the last word, like it or not. So much for scientific discourse. The Campbells certainly could have chosen the path taken by Denise Minger - posting all discussion, whether "civil" or not, and choosing the reply to those questions or issues that are clearly intended to foster scientific discussion, and ignoring ad hominem attacks etc. Dr. Campbell's chosen course speaks to his true motivations.

If you have questions you posted to Campbell's site which did not make it through moderation, I invite you to repost in the comments here. Others can then see exactly what offended Dr. Campbell so greatly that he opted out of the discussion.

Friday, July 16, 2010

Going Bananas

I got an "interesting" comment on my last post about Denise Minger's critique of "The China Study". It's the one from "durianrider" - check it out, particularly his "challenge". I've already answered the challenge, but invite others to also provide information about any elite non-vegan athletes they may know of. I have no illusions that we'll change durianrider's mind, or that of any "true believer", but the way to counter misinformation is with good information. Individuals need all the information they can get to make informed decisions, so let's make sure they get it, and support their right for informed choice. Personally, if you choose to be a vegan, that's fine with me. I have no stake in your personal lifestyle choice, but I do want to help people at least make that choice an informed one, rather than one based the propaganda of zealots.

And T. Colin Campbell, if you're out there, let's see if you have the courage of your convictions. I have a Ph.D. and was an academic research scientist for many years, so I should be "worthy" of scientific discourse with you. And discourse is at the root of scientific progress. How can you expect to educate people like me on your views if you are unwilling to discuss them with opponents in a public forum?

Related note: durianrider is also one of the principals of the site, along with "freelee". Some of the discussion on the post "Debunking the China Study Critics" is pretty interesting, from a sociological point of view. I am going to try registering for the site, and see if they have any willingness to let in opposing views. The registration page and forum guidelines make me suspect they are intolerant of those who might not agree with them, e.g. this quote:

We will not tolerate "anti-fruit" posts or advice that recommends calorie restriction/or the suggestion that others are "overeating on fruit", also recommending others restrict their water intake will not be supported on 30BaD, these threads will be deleted and you will be given a warning. This advice is not only unproductive but dangerous to the health of our members.

One of the best signs of dogmatic belief is the intolerance of information which contradicts said belief. I'll reserve judgment on until my application gets accepted or rejected, as I plan to make it quite clear that I will be providing evidence that runs counter to their mission.

For my part, I welcome discussion from all corners, provided it is reasonably civil (i.e. contains actual information rather than emotional spewing). The definition of rationality is that two people with the same information will draw the same conclusions. But the only way those two people can achieve the same state of information is through communication. Even if you completely disagree with my views, there's a reasonable chance that I will learn something from you which may help me make better choices. So bring it on!

Friday, July 9, 2010

The China Study: Crushed by its Own Data

You may have already seen this outstanding analysis of the data from "The China Study". If you haven't, I highly recommend you give it a read. It's long, but well worth the effort. Readers of this blog know my opinion of T. Colin Campbell and his "scientific" work. Now somebody has taken the time to actually crunch the numbers, using Campbell's own data to demonstrate that his conclusions are baseless (at least when confined to this data), and probably the result of confirmation bias.

I also love the observation that, despite his constant whining about the "dangers of reductionism" in science, Campbell's entire argument against animal protein really hinges on a strongly reductionist experiment, namely the isolated effect of casein fed to rats in large doses. Snap!

Readers know of my criticisms of classical statistics, but it should be noted that I don't really have a problem with the mathematics, but the application. Math is what it is, either right or wrong. My issue is that classical statistics is used incorrectly, to draw inferences about hypotheses, when the underlying mathematical framework has nothing to do with inference. The key problem is that "statistics" are just numbers derived from data, like correlations. They don't say anything about a hypothesis: you will calculate the same correlation between two datasets, regardless of your hypothesis about what causes that correlation. Anyway, I don't want to get off on a rant. My point here is that the author, Denise Minger, does an excellent job of confining her analysis and conclusions within the bounds of what classical statistics can tell you. And along the way, she does a great job of demonstrating how easy it is to fool yourself (as T. Colin Campbell did - repeatedly) by over-interpreting these numbers which, in the end, cannot tell you anything more than what's in the data.

Ms. Minger has also done a great service in providing a concrete example of the issues in observational studies. You've likely read often that epidemiological studies are of little use in distinguishing between competing hypotheses. Now you have an example, replete with numbers. Ms. Minger demonstrates in several cases how a seemingly "obvious" conclusion vanishes once you dig into the large number of uncontrolled variables inherent in all observational studies. It's easy to find correlations in large datasets with many uncontrolled variables. The problem is that people take these correlations to mean more (or less) than they really do in terms of supporting/undermining a particular hypothesis, and the conclusions they draw are essentially ad hoc, not based on any rigorous mathematical analysis, but rather hand-waving about what is "obvious". An oft-quoted example is that men who shave daily have a higher incidence of heart disease. It is "obvious" that heart disease is not caused by shaving, right? Or is it? There's a whole lot of other information that goes into that judgment. We generally take this sort of thing for granted, especially when made in pronouncements from "esteemed" scientists like T. Colin Campbell. But if you dig into the reasoning behind these conclusions, you generally find a tangled web of assumptions, hypotheses assumed to be true, but which have varying (if any) actual evidence to support them. Ms. Minger does a great job of teasing these out of Campbell's reasoning, and demonstrating how the data itself provides little evidence one way or another, precisely because it cannot distinguish between the potential effects of the many intertwined and uncontrolled variables.

Anyway, enough of my babbling. Go read the article, you'll be glad you did (unless you're an uncritical fan of T. Colin Campbell, in which case you've got bigger problems).