Ionian Enchantment

Cyclone Roberta - FAKE

Ionian.Enchantment@gmail.com (Michael Meadon) — Thu, 19 Nov 2009 11:01:00 +0000

A public service announcement: the rumors and emails (example after the jump) doing the rounds that KwaZulu Natal is about to be hit by a "tempestuous cyclone" is fake, false, a hoax, bollocks, and completely made up. (There is a warning of heavy rainfall - "in excess of 50mm in 24 hours" - but there is no cyclone). Some observations: South Africa's east coast is very rarely hit by cyclones and email hoaxes are plentiful. Put these facts together, apply a bit of common sense, and you get doubt. And doubt should motivate some fact checking (Google is your friend)... If you did so, you'd find this East Coast Radio article saying it's fake, this cyclone tracking service showing no cyclones heading South Africa's way, and this blog entry by the SA Weather and Disaster Information Service saying it's a hoax.

Doubt will set you free.

The fake email:

HIGH IMPORTANCE

This is a blanket warning to all citizens of Kwazulu Natal and the South-Eastern coastal regions of South Africa.

A tempestuous cyclone (Roberta) was sighted just off the West coast of Madagascar at approximately 17h00, is moving Eastbound at a rate of 32 knots. When first observed, it was thought that Cyclone Roberta would dissipate once it met with the higher pressure cells towards the South-East. However, due to the unforeseen ebbing pressures we have seen off the Southern African coast since early this morning, the cyclone is unlikely to abate.

Please be forewarned that the Southern and South-Eastern regions of South Africa, particularly Kwazulu Natal, will in all probability experience the most violent winds and thunderstorms to date. It is strongly recommended that residents of Kwazulu Natal seek secure shelter. The cyclone is thought to hit our coast at approximately 15h30 today, 19th november We urge everyone to take every possible measure to seek secure refuge again this heavy weather pattern.

Fun with blasphemy

Ionian.Enchantment@gmail.com (Michael Meadon) — Wed, 18 Nov 2009 13:01:00 +0000

So September 30th was Blasphemy Day International, and the Center for Inquiry has released their blasphemy contest winners. Contestants were supposed to create blasphemous statements no longer than 20 words. The winners:

“Faith is no reason” (by Ken Peters)
“There’s no religion like no religion” (Daniel Boles)
“I wouldn’t even follow your god on Twitter” (Michael Hein)
“The reason religious beliefs need protection from ridicule is that they are ridiculous” (Michael Nugent), and,
“I survived the God virus” (Perry Bulwer)

I vote for the 4th one: I'd totally buy a t-shirt with that on.

Oh. And just for fun, my five favorite blasphemous pictures.

Encephalon #78

Ionian.Enchantment@gmail.com (Michael Meadon) — Wed, 18 Nov 2009 08:22:00 +0000

The 78th edition of the mind/brain/psychology/etc. carnival Encephalon is out at Providentia. Posts to check out: Generally Thinking on the Buddhist brain, Brain Stimulant on neurorobotics, and The Neurocritic on unusual sexual changes due to various types of brain damage (including a kind of tumor-induced pedophilia).

My posts on estimating formidability from bodies and faces were featured.

Picture: Family chain-mail fun...

Ionian.Enchantment@gmail.com (Michael Meadon) — Sun, 15 Nov 2009 12:22:00 +0000

Yup.

(source).

Anti-vaccination and South Africa's measels outbreak

Ionian.Enchantment@gmail.com (Michael Meadon) — Sun, 15 Nov 2009 12:16:00 +0000

South Africa is in the grip of a measles epidemic (luckily confined primarily to the province of Gauteng), with 2000 cases and 4 deaths. The culprit? Parents not vaccinating their children (among other things) due to the fear that jabs can cause autism. Before getting into a bit more detail, I want to praise reporter Kim Hawley at the Times (of South Africa) for getting the story exactly right: her article emphasized the unscientific nature of such worries. Well done.

A press release issued by South Africa’s department of health contains the following revealing paragraph:

One striking feature of this latest outbreak is that while it has affected children of the poorer communities, it has also been concentrated among relatively well-off children, predominantly in the 15-19 year old age group. We believe that in both groups, the underlying cause has been failure by the parents or guardians to take children for immunization i.e. both the initial and follow-up doses.

It seems likely that among the well-off children (and much less so among the poorer children, where other factors were likely involved) the cause is parents’ fears over vaccines causing autism. The source of these fears is the anti-vaccination movement (and their idiotic celebrity sponsors) that has spread unscientific claims that either the MMR vaccine causes autism or that thimerosal (until recently a common vaccine ingredient) causes autism. These claims have been disproved beyond reasonable doubt. Being more influenced by Britain than America, it's probable that the MMR claim is most relevant to South Africa, so I'll focus on that. The source of the MMR-autism worry was a deeply flawed, and possibly fraudulent, 1998 study by Andrew Wakefield and colleagues, that was merely a case series of 12 subjects (that is, a series of 12 anecdotes) that could not, in principle, determine whether there was a causal link. Moreover, Wakefield had undisclosed conflicts of interest (he received £50,000 in legal aid money from lawyers preparing a case against MMR – over the years he received over £434,000 from such cases). Wakefield is also currently under investigation by the UK's General Medical Council on charges of serious misconduct, and he might lose his license to practice.

Just because the original study was flawed does not mean, of course, that the there cannot be a link between vaccines and autism. But, as I said above, numerous subsequent studies have found no such link. In other words, there is no good reason at all to think vaccines cause autism. Note to parents: VACCINATE YOUR CHILDREN. Dammit.

(via The Lay Scientist)

Lazy linking...

Ionian.Enchantment@gmail.com (Michael Meadon) — Fri, 13 Nov 2009 12:35:00 +0000

Your semi- quasi- pseudo- weekly dose of Lazy Linking...

"Grandma Plays Favorites"

A report by ScienceNOW on fascinating research on grandparent kin-altruism. According to the grandmother hypothesis, older women survive well past menopause (or have it in the first place) because over evolutionary time the marginal benefits of taking care of grandchildren were larger than the marginal benefits of additional children (possibly because the chance of having a healthy baby decreases dramatically with age).
Various studies have been done to test this hypothesis, but the results have been mixed. Now Fox et. al. have a proposal that could account for these mixed findings: that altruism varies by sex-linked chromosomes. In terms of the sex-chromosomes, paternal grandmothers are on average 50% related to their granddaughters, but not related to their grandsons at all. (Since a male is XY and a female XX, a boy must get his Y chromosome from his father and his X chromosome from his mother). Maternal grandmothers, on the other hand, will on average share 25% of their sex-chromosomes with both grandsons and granddaughters.
In other words, if you are a paternal grandmother it makes sense to dote on granddaughters (again, at least when it comes to sex-chromosomes) and if you are a maternal grandmother, it makes sense to dote equally. And, apparently, controlling for these different genetic interests makes sense of the previously-inconsistent data.

"Who's the Scientist?"

Seventh graders describe scientists before and after a visit to Fermilab. Not surprisingly, meeting an actual scientist changes children's perceptions dramatically, and for the better.

"Clever fools: Why a high IQ doesn't mean you're smart"

Excellent New Scientist piece on how IQ does a pretty bad job of measuring intellectual competence. The problem with people like George Bush, I have long thought (and the article basically agrees), isn't that they are stupid, it's that they subscribe to an unjustified epistemology in which they elevate intuition, ideology, and "gut feelings" over critical thinking and science. As I have said time and again, the human mind is prone to innumerable biases and rigorous thinking, humility, open mindedness and a reliance on reason are the only antidotes.

"Creationism Taught as Science in South African State Schools"

The title says it all. Depressing, annoying, unacceptable.

"A Language of Smiles"

It has been known for a long time that the simple act of smiling can lift your mood and frowning can sour it. The most excellent Olivia Judson puts these findings together with the fact that different languages require different frequencies of mouth movements, some of which resemble smiling and others frowning. So if language A has a lot of sounds requiring speakers to pull a smile-like face, and language B lots of sounds requiring a frown-like face, we might have an interesting (but subtle and partial) explanation for different national cultures. German, for example, contains a lot of vowels that make you frown...

"Reforming libel law: A city named sue" (registration required).

The Economist argues, entirely convincingly, that England's libel laws are archaic and damaging to free speech. Some American media organizations are now actually threatening to stop publishing in England and blocking access to their websites there.
Good ideas for reform include shifting the burden of proof to the claimant and capping damages. Dear House of Commons: do something, dammit.

"Probably guilty: Bad mathematics means rough justice"

Innumeracy - the inability to deal competently with basic mathematics and statistics - is a Bad Thing. (As John Allen Paulos has argued). As this article explains, innumeracy in the legal system leads to miscarriages of justice.

"Next-gen PhDs fail to find Web 2.0's 'on-switch'"

The Times Higher Education Supplement reports on a survey that suggests 'Generation Y' graduate students have not embraced Web 2.0. C'mon guys... RSS and blogs are particularly valuable tools: use them. (I have my doubts about social bookmarking).
A weakness: the study (at least as reported here) did not compare patterns of use among the Ph.Ds to the wider population of Generation Y.

"Face the Facts - and End the War on Drugs" - Johann Hari

It so obvious I find it embarrassing to have to point it out: governance ought to be evidence-based. Alas, policymakers are notoriously immune to the facts, especially so on issues people are prone to go into moral panic about. The evidence with regards to drugs is overwhelming and clear: prohibition causes far more harm than good. Deal with it like alcoholism: decriminalize and treat it like a public health issue.
See also: a piece in this week's Economist on how drugs are becoming 'virtually legal' due to laws not being enforced.

"How did I get Here?"

Wonderful post over at Science, Reason and Critical Thinking tracing various contingent links between events, books and so on that led him to where he is now. Cue a cliche about the butterfly effect.

"Cell Size and Scale"

Awesome little interactive on the Learn.Genetics site showing the size of various biological parts and organisma, ranging in scale from a rice grain to a carbon atom. It reminds me of that awesome video I posted a while back on the size of the planets compared to the Sun, and the Sun compared to other stars.

Adaptations for the visual assessment of formadibility: Part II

Ionian.Enchantment@gmail.com (Michael Meadon) — Thu, 12 Nov 2009 10:50:00 +0000

In Part I of this series, I summarized the experiments and findings of Aaron Sell and colleagues' paper "Human adaptations for the visual assessment of strength and fighting ability from the body and face". In Part II, I evaluate their claims.

The evidence Sell et. al. present seems compelling with regards to proposition (i): adults appear to be able to make remarkably accurate estimates of upper-body strength from even degraded cues such as static images of faces. As I noted in Part I, however, the truth of propositions (ii) (that this ability is an adaptation) and (iii) (that upper-body strength determines formidability) are more doubtful. I will assess the evidence for each of these claims, starting with the latter.

Concluding that the truth of (i) implies people can visually estimate fighting ability – the likelihood of an individual prevailing in combat – requires us to assume (iii): that upper-body strength is a good proxy for formidability. Unfortunately, Sell and his colleagues provide only indirect, theoretical, reasons for supposing this is true: namely, the greater sexual dimorphism between upper-body and lower-body strength and the fact that the driving force of certain weapons is largely a function of upper-body strength (p. 576). , These considerations, however, seem far from decisive and while it is certainly plausible that upper-body strength is a very (or the most) important component of fighting ability, rigour clearly requires direct empirical evidence. Other likely components of formidability – speed, stealth, skill, bravery, etc. – are either orthogonal to, or even negatively correlated with, high upper-body strength. There are doubtlessly multiple complex tradeoffs between the different components of fighting ability and thus there are likely multiple local-optima in ‘formidability space’. The point of this argument is that without an empirical determination of the magnitude of the correlation between formidability and strength, Sell et. al.’s conclusion rests on an (admittedly plausible) assumption. More importantly, however, it is at least possible that uncontrolled-for components of formidability may introduce confounds or complications that could influence the correlation between perceived and actual strength in either direction. For example, there may be a semi-independent ability to estimate fighting skill, and, depending on the direction of the correlation between upper-body strength and this skill, it may lead us to under- or overestimate the accuracy of visual assessment of fighting ability. The problems around claim (iii), however, are comparatively minor; the major weakness of Sell et. al.’s paper lies with their claim that the ability to visually estimate formidability evolved by natural selection.

An adaptationist claim like (ii) is significantly more complex than other types of propositions because it entails assertions about the past and about design (Symons, 1992: 140-141). As Richard Burian has explained, when one asserts some trait is an adaptation, “one is claiming not only that the feature was brought about by differential reproduction among alternative forms, but also that the relative advantage of this feature vis-à-vis its alternatives played a significant causal role in its production” (1983: 294). In other words, the assertion that the ability to estimate formidability is an adaptation entails that it evolved over deep time by natural selection, and that the ‘function’ of this psychological trait and its neurological substrate is to detect formidability. To say some feature is an adaptation, then, is a compound claim involving multiple independent propositions, each of which requires substantiation. Sell et. al., it seems to me, fall short of this evidentiary standard, not least because they never mount an explicit defense of (ii), despite the fact that they have the onus and that it is a crucial aspect of their paper. There are, nonetheless, a number of arguments that can be extracted from the paper (or advanced on behalf of the authors). In rough order from least to most persuasive, these are (a) that (i) was previously unknown and that Sell et. al. predicted its existence from evolutionary considerations, (b) that comparative data indicates that such assessments are widespread and perhaps even homologous across taxa, (c) that accurate visual formidability assessment is at a minimum not highly culturally bound, and perhaps universal, and (d) the functional goodness-of-fit between the ‘design problem’ and its ‘solution’.

It seems highly significant, firstly, that Sell and his colleagues predicted the existence of a previously unknown trait – i.e. (i) – from general comparative and evolutionarily psychological considerations. It is important to be careful here, though, because it is entirely possible for (i) to be true but for (ii) to be false (but obviously not vice versa). Some philosophy of science should clarify the situation. Hans Reichenbach (1938) usefully distinguished between the “context of discovery” (the creative process of using background knowledge to invent new hypotheses and theories) and the “context of justification” (the evidence-driven process of testing hypotheses and subjecting them to peer evaluation). For example, Friedrich Kekulé von Stradonitz reportedly first imagined the six-carbon ring structure of benzene after having a dream of an ouroboros (the context of discovery). It does not follow from this, however, that benzene actually had anything to do with snakes, or that testing the idea (the context of justification) involved an ancient symbol. Similarly, even if Sell et. al. predicted the existence of an ability to make formidability estimates from evolutionary theory, it does not necessarily follow that the trait evolved. Propositions (i) and (ii) are logically and epistemically independent, and each needs to be tested against related but different sets of evidence. The fact that (i) was predicted rather than retrodicted from evolution gives as no more than prima facie reason to think it evolved and (a) is thus weak evidence for (ii).

Sell et. al. cite a large and growing body of literature that documents parallels between human and non-human conflict, including, importantly, evidence that non-human animals can visually detect formidability. If this trait is homologous across species, including humans – and that is a gargantuan if – we can be confident (ii) is true since homology suggests that the emergence and persistence of the trait is due to natural selection. It should be clear, however, that building a convincing phylogenetic case for such a widespread homology would be a mammoth undertaking, and no one, as far as I know, has yet done so. The fact that there seems to be a preliminary case for homology is at best suggestive, no conclusions can reasonably be drawn until much more science is done. In other words, were (b) true we could reasonably infer (ii), but we simply do not have enough evidence to conclude (b) is in fact true so, on current evidence, it provides minimal support.

The logic of argument (c) is the following: given that traits that reliably emerge in developmentally normal individuals are likely (though not necessarily) adaptations, demonstrating that the ability to visual estimate formidability is a human universal would strongly favor proposition (ii). As we saw above, Sell et. al. did demonstrate convincingly that the trait is not highly culturally contingent: if US subjects can estimate the upper-body strength of culturally distant men, the ability must be fairly general. The usual criterion for being admitted to the list of human universals (Brown, 1991), however, is having been documented in a large number of (or ideally, all) cultures, which is obviously not true of visual strength assessments. More significantly, the data are compatible with a wide range of scenarios, from near-parochialism to universality. For one thing, only US subjects ever made strength estimates so the evidence is compatible with the hypothesis that the ability is culturally-insensitive (it works on everyone) but that only US subjects have it. Similarly, it is possible US subjects would not be able to make accurate formidability estimates of men from even more distant cultures – the Hadza, say, or Mongolians. While I think neither of these scenarios likely, we do not have the empirical evidence to reject them (or many other hypotheses), so (c) also provides somewhat equivocal support for (ii).

By my reckoning, the authors' most convincing (though entirely implicit) argument for (ii) is the functional or specialized ‘fit’ between the survival problem and the structure evolved to ‘solve’ it. In their classic “The Psychological Foundations of Culture” (pdf) Leda Cosmides and John Tooby set out the general logic of this argument as follows:

The conspicuously distinctive cumulative impacts of chance and selection allowed the development of rigorous standards of evidence for recognizing and establishing the existence of adaptations and distinguishing them from the non-adaptive aspects of organisms... Complex adaptations are usually species typical; moreover, they are so well-organized and such good engineering solutions to adaptive problems that chance coordination between problem and solution is effectively ruled out as a plausible explanation. Adaptations are recognizable by “evidence of special design” (Williams, 1966); that is, by recognizing certain features of the evolved species-typical design of an organism as “components of some special problem-solving machinery” (Williams, 1985: 1) that solve an evolutionarily long standing-problem. Standards for recognizing special design include factors such as economy, efficiency, complexity, precision, and reliability, which, like a key fitting a lock, render the design too good a solution to a defined adaptive problem to be coincidence. (Cosmides & Tooby, 1992: 62 – 63; references other than to quotations removed).

The canonical example of such a ‘special problem-solving machine’ is the human visual system (the eye and the attached neural architecture): the system is far too intricate to have come about by chance. Given that natural selection is the only known natural explanation for functional complexity (Dawkins, 1986), invoking the former is our only (non-Skyhook invoking) option when confronted by a sufficiently improbable instance of the latter. The extent to which argument (d) supports proposition (ii), then, rests on whether visual formidability detection exhibits functional complexity not explicable without reference to natural selection. I will argue that, while the evidence is somewhat equivocal and uncertainties remain, on balance (d) warrants tentative acceptance of (ii).

It is important to emphasize at the outset, however, that it is possible for strength assessment to be a by-product of other visual adaptations. It is uncontroversial that the visual system and its various components are adaptations, so only natural selection could explain the very existence of vision. But with (ii) Sell et. al. claim that in addition to the other visual adaptations – edge detectors, facial recognition, retinotopic maps, etc. – there is an information processing mechanism in the brain specifically adapted to analyze the incoming visual data in order to assess formidability. In other words, the human brain contains a ‘device’, coupled to pre-existing visual and cognitive adaptations, to extract and process information from human bodies and faces and it exists just because without it accurate strength and formidability estimates would not be possible (at least not without extensive learning). The latter clause is important. Nobody posits the existence of a “tattoo detection module” since the ability to detect tattoos ‘comes free with’ – is a by-product of – the general visual system. Sell et. al. are saying, in effect, that formidability detection is not like tattoo detection: it does not come free with vision because it requires additional specialized processing. It seems to me that the case for such specialized processing when estimating upper-body strength is rather weak when the body is visible. As Daniel Dennett has pointed out:

since in the case of humans (and only humans) there is always another possible source [for] adaptations… – namely culture – one cannot so readily infer that there has been genetic evolution for the trait in question. Even in the case of nonhuman animals, the inference from adaptation to genetic basis is risky when the adaptation in question is not an anatomical feature but a behavioral pattern which is an obvious Good Trick. For then there is another possible explanation: the general nonstupidity of the species… [T]he more obvious the move, the less secure the inference that it has to have been copied from predecessors – specifically carried by the genes. (1995: 485).

Assuming the prior existence of a complex visual system, determining upper-body strength when the body can be seen plausibly only requires the obvious Good Trick of adding up muscle mass. In other words, when the body is visible accurate strength estimation arguably does not require special problem-solving machinery. The case is quite different, however, with regards to strength estimates made when only the face is visible. Recall that Sell et. al. demonstrated raters made strength judgments from face-only photographs that are highly correlated with measured strength: the independent effect of upper-body strength was γ=0.31 (p=10-11) in the US group, γ=0.18 (p=0.0003) for the Tsimane subjects, and γ=0.43 (p=10-5) for the Andean participants. Importantly, there does not seem to be an obvious Good Trick that could account for these findings. To see what I mean, compare the following two photographs:

On the left is Kimbo Slice, a martial arts fighter; on the right is South African rugby player Bakkies Botha. Concluding that Kimbo Slice is a formidable man from the above photograph seems straightforward and rather unimpressive: you can just see how big he is and that he was power muscles. Determining that Bakkies Botha is formidable from the above photograph (and he is - he's one of the toughest men in world rugby and South Africa's enforcer), however, would be far more impressive: doing so requires making non-obvious inferences. The most plausible mechanism that links strength and facial morphology is that both traits covary with long term exposure to testosterone (p. 581). A facial structure indicative of a history of high levels of circulating testosterone is therefore ipso facto a reliable marker of upper-body strength. Clearly, the ability to determine which faces show signs of high levels of testosterone is a non-trivial engineering problem, and thus the ability is very unlikely to ‘come free with’ a visual system. Accurate strength estimates from faces therefore strongly implicates specialized and functionally complex cognitive machinery. Given how credible it is that formidability detection is fitness enhancing – by informing decisions on whether to fight or flee, thus avoiding confrontations with more powerful opponents – it is likely that natural selection for such an ability played a ‘significant causal role in its production’. In other words, (d) provides good (though not overwhelming) reason to think (ii) is indeed true: formidability detection is an adaptation that evolved over deep time by natural selection.

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Sell, A., Cosmides, L., Tooby, J., Sznycer, D., von Rueden, C., & Gurven, M. (2009). Human adaptations for the visual assessment of strength and fighting ability from the body and face Proceedings of the Royal Society B: Biological Sciences, 276 (1656), 575-584 DOI: 10.1098/rspb.2008.1177

Skeptics' Circle #123

Ionian.Enchantment@gmail.com (Michael Meadon) — Wed, 11 Nov 2009 14:18:00 +0000

The 123rd incarnation of the Skeptics' Circle is out at Blue Genes. Posts to check out: The SkepVet Blog on CAM and religiosity; The Evolving Mind on cognitive biases; and Skeptic North on the lack of evidence for the healing power of prayer.

Skeptics in the Pub Durban

Ionian.Enchantment@gmail.com (Michael Meadon) — Tue, 10 Nov 2009 13:28:00 +0000

There's been a Skeptics in the Pub Joburg for a while now, so it's about time Durban got in on the action too! Our inaugural SIP is on Wednesday, November 18th from around 19:00 at Badgers in Davenport Center. (Tangent: Badger, Badger, Badger...). All are welcome! Check out the event on Facebook.

I've created a Google Map with the exact location (embedded below). Note that maps.google.co.za was recently significantly upgraded (for the upcoming Soccer World Cup), so it's now an extremely useful resource. Click on the pin on the map, and then select 'Get Directions: To Here', slap in where you are, and Google will recommend the best route. All hail Google.

View Badgers in a larger map

Just note that we might have to change the venue: if a lot more people want to come, Badgers will be too small. If we do need to change venues, it will be in the same area though (likely in Buxton's center). You'll be informed of any changes if you confirm attendance on Facebook and I'll put up any updates on my blog.

Adaptations for the visual assessment of formidability: Part I

Ionian.Enchantment@gmail.com (Michael Meadon) — Tue, 10 Nov 2009 11:12:00 +0000

In the last couple of years there has been an explosion in research on faces and what can be inferred from them. It turns out, for example, that you can predict electoral outcomes from rapid and unreflective facial judgments, that women can (partially) determine a man's level of interest in infants from his face alone, that the facial expression of fear enhances sensory acquisition, and much, much else. A particularly interesting addition to this literature is Aaron Sell and colleagues' paper, "Human adaptations for the visual assessment of strength and fighting ability from the body and face". Sell et. al. hypothesized that human beings possess evolved psychological mechanisms 'designed' to estimate the fighting ability (or physical formidability) of conspecifics - i.e. other Homo sapiens sapiens - from minimal visual information. An ancillary, but important, claim the authors also make is that formidability is largely a function of upper-body strength and thus the latter is a suitable proxy for the former. To summarize for clarity, Sell et. al. claim that:

(i) people can estimate the formidability of others from visual cues of their bodies and faces,
(ii) this ability is an adaptation, and thus evolved by natural selection, and
(iii) upper-body strength is the single most important determining factor of fighting ability.

The authors’ rationale for the first two hypotheses stems from the observation that in social species such as humans, ‘the magnitude of the costs an individual can inflict on competitors largely determines its negotiating position’ (p. 575). That is, formidability is often an important component of an organism’s ability to compete in zero-sum games (notably, access to limiting resources). Given the dangers of physical confrontation, a rapid visual assessment of the formidability of an opponent could be extremely beneficial because it would allow an individual to weigh up its chances of success, and thus choose to fight only when there is a reasonable prospect of victory. Indeed, Sell et. al. note that the widespread so-called ritualized animal contests are best interpreted as joint demonstrations and assessments of formidability, with physical violence usually ensuing only when individuals are closely matched. If the ability to visually estimate a competitor’s formidability was indeed adaptive, and if violence was frequent and recurrent throughout human evolutionary history (as is likely the case), it is not unreasonable to expect natural selection to have forged mechanisms to make such estimates. Sell and his colleagues tested hypothesis (i) empirically in a number of studies and the evidence seems to bear it out overall. While the truth of (ii) is more doubtful, I will argue that, pending further research, it is reasonable to accept it preliminarily for a number of reasons. Finally, I will argue the lack of empirical evidence in the study for (iii) is problematic but not decisively so: it is clear that there is a correlation between upper-body strength and formidability, but we do not know how strong this correlation is so it is difficult to judge how good a proxy the one is for the other.

After the jump, I summarize Sell et. al.'s primary findings (though I leave out one of their experiments). In Part II - coming later in the week - I evaluate their paper.

Broadly speaking, Sell et. al. divided their subjects into two groups: the stimulus subjects (who provided the target photographs and strength measurements) and the judgment subjects (who rated the strength of the men in the target photos). The first group filled out a questionnaire, posed for photographs, had their body measurements taken (e.g. weight, height) and then had their strength measured in a number of ways. The photographs were then standardized and edited, and the target individuals’ upper-body strength measurements were combined to create a composite score for each. The judgment group was then presented with various versions of the photographs and asked to rate the physical strength of the target individuals. Specifically, these subjects were asked to: “Please rate the following [men/bodies/faces] on how physically strong you think the man is compared to other men of his age” on a 7-point Likert scale (1 = very weak, 7 = very strong). In the first study, 59 male undergraduates at the University of California Santa Barbara (UCSB) were recruited at a campus gym, their photos were taken and so on as described above. Each participant’s upper-body strength was then measured on four weight-lifting machines in random order (arm curl, abdominal crunch, chest press, and super long pull) and his lower-body strength was measured with a leg-press. The subjects also posed for two color photographs: (a) full-person, without a shirt, standing next to a male experimenter for scale, and (b) face-only. (Dress was standardized and subjects were asked to keep a neutral expression). The images were then edited to create three sets of photographs: face-only, cropped below the jaw-line (as in the top row of the picture below), full-person (not pictured), and body-only with the face removed (as in the bottom row).

After these stimulus materials were created, an additional 142 UCSB undergraduates (59 female) were asked to rate one set of 59 images (full person, body only or face only). The findings robustly supported the authors’ hypothesis: the average ratings of the men’s strength correlated with their actual upper-body strength at r=0.71 (p=10^-10) for photographs of the whole person, at r=0.66 (p=10^-8) for the body alone, and at r=0.45 (p=0.0003) for the face alone. These results, though, relate to perceived strength, not to perceived formidability itself. So to test whether judgments of strength track judgments of fighting ability, the researchers asked another group of 37 subjects (25 female) to “Please look at the following photographs of men and rate them on how tough each would be in a physical fight – how likely he would be to beat his opponent”. The correlation between the two types of ratings was nearly perfect: r=0.96 (p = 10^-32).

Using hierarchical linear modeling (HLM) Sell et. al. further established that upper-body strength specifically, and not lower-body strength or other features such as height or age, largely determined perceived strength. In the first HLM, the target variable was rated strength and the predictor variables were upper-body strength and leg strength as measured on the leg press. Again, the results supported the authors’ hypothesis: in all cases, the predictive contribution of upper-body strength was large and highly significant, whereas the contribution of lower-body strength was equivocal, modest and of mixed significance. For face only photographs, upper-body strength was γ=0.31 (p=10^-11) but leg strength γ=-0.09 (p=0.003); for body only, upper-body strength was γ=0.44 (p=10^-19) but leg strength γ=0.007 (p=0.81); and for full person photos, upper-body strength was γ=0.41 (p=10^-12) but leg strength γ=0.06 (p=0.03). Clearly, then, perceived strength is more a function of upper-body than lower body strength. The authors also created a HLM that determined to what extent measured upper-body strength, age, weight or height predicted rated strength when controlling for the other three variables. (That is, this HLM showed the independent effect of each variable). The results are summarized in the following table:

	Independent effects of target measurements on ratings
Rated Strength	Γ	P
Full person photos
Strength	.50	10^-14
Height	.36	10^-8
Weight	-.16	.004
Age	.06	10^-4
Body alone photos
Strength	.52	10^-19
Height	.36	10^-9
Weight	-.21	.001
Age	.10	10^-7
Face alone photos
Strength	.22	10^-8
Height	.05	.10
Weight	.07	.05
Age	.04	.10

Clearly, the two most important components of perceived strength are measured upper-body strength and height (As Sell et. al. note, height determines reach, which is likely an important component of formidability). In each case, however, the independent effect of upper-body strength is statistically significant and larger than any of the other variables. In other words, (a) raters can accurately estimate a man’s upper-body strength from static visual images (significantly, including images of just faces), and (b) perceived strength is not a function of overall body size, but of upper-body strength and, to a lesser extent, height.

The data cited above, however, are limited by the fact that both the stimulus and judgment groups were recruited from the same culture and thus leave the question of how generalizable the findings are open to question. Sell et. al. partially addressed this concern by recruiting two further groups of stimulus subjects from non-US cultures. In the first case, fifty-three adult Tsimane men (a group of semi-sedentary forager-horticulturists who live in the lowlands of Bolivia) were photographed and had various body measurements taken. The photos were edited to present the face only (see below) and a composite score of upper-body strength was created for each using measurements of their chest, shoulder, flexed bicep circumference and handgrip strength. Thirty-two UCSB undergraduates (17 female) were then asked to rate the men in the same way as in the first study.

The second non-US stimulus group was recruited from an Andean population of herder-horticulturalists from the province of Salta in Argentina. Twenty-eight adult men were photographed, had various measurements taken and then a composite score of their upper-body strength was created from their flexed bicep circumference and a direct measure of chest/arm strength. Another twenty-eight USCB students (19 female) then rated the face only photos, again in the same way as in the other studies. The results from both experiments robustly supported the hypothesis that people can make accurate judgments about the formidability of men even from different cultures. Recall that in the first study the correlation between actual strength and strength estimated from facial photographs was 0.45 (p=0.0003); in the Tsimane study the correlation was even stronger at r=0.52 (p=0.0001), and the correlation was similarly high for the Andean stimulus group with r=0.47 (p=0.01). As in the US study, the researchers created HLMs for the Tsimane and Andean groups and again found perceived strength is largely a function of upper-body strength, and not any of the other variables. The independent effect of measured strength (i.e. controlling for height, weight and age) was γ=0.18 (p=0.0003) for the Tsimane subjects, and γ=0.43 (p=10^-5) for the Andean participants. Interestingly, none of the other variables were significant in the Tsimane study, but in the Andean study age had a very strong negative effect with γ= -0.22 (p=0.0002). The overall results, however, are clear: raters can accurately estimate the upper-body strength of men from different cultures based on nothing more than a photograph of his face.

Part II is up...

-------------------------

Sell, A., Cosmides, L., Tooby, J., Sznycer, D., von Rueden, C., & Gurven, M. (2009). Human adaptations for the visual assessment of strength and fighting ability from the body and face Proceedings of the Royal Society B: Biological Sciences, 276 (1656), 575-584 DOI: 10.1098/rspb.2008.1177.

Picture: Fun with Venn Diagrams

Ionian.Enchantment@gmail.com (Michael Meadon) — Sat, 07 Nov 2009 14:46:00 +0000

Some random fun...

(via)

African science/skepticism blogrolling for October

Ionian.Enchantment@gmail.com (Michael Meadon) — Tue, 03 Nov 2009 06:47:00 +0000

For those of you new to my blog, I've for a long time now been trying to foster better cooperation and communication between those dedicated to science and reason on the African continent. Part of that initiative is our carnival, another is this blogroll (which is Africa wide, though it started as South African) and the last is our mailing list on Google Groups...

So this is the updated blogroll - there are quite a few new blogs, which is a very good thing. If you know of any more, please let me know and please consider adding the blogroll to your own blog. Also, please do a post like this one linking to everyone on the list - it promotes all of our blogs.

Ionian Enchantment turns two...

Ionian.Enchantment@gmail.com (Michael Meadon) — Tue, 03 Nov 2009 04:30:00 +0000

So today is my 2nd blogiversary -- it was November 3rd, 2007 when I wrote my first post, ingeniously entitled "Welcome...". As I noted on the occasion of my first blogiversary, things haven't turned out as I thought it would, and my blog is much the better for it. While Ionian Enchantment has remained unabashedly intellectual/academic (read: nerdy) and while I've (almost) consistently steered clear of politics and other distractions, my remit has steadily expanded and my style has become quite a bit more informal. (I am told this is easier on the eyes, which confuses me a bit since academese is my mother tongue). I must say, I'm very glad I started blogging, not only have I learned a hell of a lot over the last two years, indirectly I even met my lovely fiancée through blogging. (Now that's geek-cred for you. If only I could convince her to have a pirate wedding....). Oh. And thanks to Steve and the SGU gang for convincing me to look into this whole "blogging thing". (A full chronology: joined Facebook, joined the FB group "Atheists, Agnostics and Non-Religious", found out about SGU on the discussion forum there, listened to SGU and learned about the skeptical movement and blogging, read blogs, started my own blog, heard about skeptics in the pub Joburg, went to pub, met girl...).

Anyway, yay to me and all that jazz... (Is it just me or do I use far too many brackets in this post? [nah]).

Carnival of the Africans #12

Ionian.Enchantment@gmail.com (Michael Meadon) — Sat, 31 Oct 2009 15:08:00 +0000

Welcome to another (somewhat late) edition of Carnival of the Africans the best and only carnival for African scientists, rationalists and skeptics...

We start this month's edition with a few newcomers:

The Academy of Science of South Africa launched a blog a while back and recently did a cool rundown of new papers in the South African Journal of Science.
Geekery has posts on the top 10 craziest geek quotes and Geek God: Mark Shuttleworth.
Hello Universe, This is Nessie writes about discrimination against atheists on the South African bench.
Also new is Blaize (who is coming to UKZN next year, yay!) at Bomoko and other nonsense words with a post on how a contradiction leads to any and all conclusions.
Tauriq Moosa covers that potato faith dude Angus Buchan, and...
Rounding off the newbies (well, bloggers new to me...) is Lenny on superstitious beliefs about Diwali and the weather...

On the the familiars...

Simon Halliday, bless his soul, actually submitted a post to this edition (so I didn't have to forage on his blog), so I'll give him pride of place. He has a fascinating piece on whether gender affects risk aversion (hear the evolutionary psychologists stir...)

Jacques Rousseau (who used to lecture me at UCT, btw) at Synapses has two posts in this edition: on how faith kills and Blasphemy Day.

The Skeptic Blacksheep (aka Michelle) reports that a psychic, amazingly, claims to have contacted Michael Jackson. Sigh.

Next up is Angela of The Skeptic Detective who blogged about a deeply boring psychic fair in Durban (I was there: yes, it was that boring). She also demolishes another idiotic chain mail doing the rounds, this time about snakes in kiddies' ball pits. (People really need to learn how to spot shopped pictures).

Tim at Reason Check does a great job of taking on Marietta Theunissen, a notorious and frankly dangerous 'psychic' who was interviewed on South Africa's 702 radio station recently. (I commented on Tim's post with a link to the mp3. Listen, if you dare).

Dr. Spurt (whose friend Dave is my supervisor...) continues his series of posts on Mad Ads (also: this) and takes on the weird claim that music not produced by a human brain is worthless.

Finally, my contributions: I attack ignorance about evolutionary psychology, explain that you have an immune system (yes!) and review a bunch of skeptical books.

We don't have a host for next month so email me if you're keen! Especially if you haven't hosted before. It'll be good for you...

Encephalon #77

Ionian.Enchantment@gmail.com (Michael Meadon) — Thu, 29 Oct 2009 06:53:00 +0000

The 77th edition of Encephalon (along with Grand Rounds) is out at Sharp Brains. Pieces to check out: Mind Hacks on the curious spike in brain activity at the moment of death (and how this may explain near death experiences), Neurophilosophy on how vision can alleviate pain, and The Neuroctitic on the same.

Skeptics' Circle #122

Ionian.Enchantment@gmail.com (Michael Meadon) — Thu, 29 Oct 2009 06:50:00 +0000

The 122nd edition of the Skeptics' Circle is out at Young Australian Skeptics. My picks: Effort Sisyphus on how skepticism has improved his health, J. R. Braden of The Gaytheists on debating a creationist cousin, and The Skeptical Teacher on that silly claim that the LHC will be sabotaged from the future...

Ida: Damp squib...

Ionian.Enchantment@gmail.com (Michael Meadon) — Thu, 22 Oct 2009 12:54:00 +0000

So remember Ida? The fossil that was going to "change everything"? That was a "missing link"? That was supposed to be a human ancestor? Well it seems all that media hype was for nothing because, according to a new paper in Nature, Ida was the ancestor of... nothing. (Or at least nothing extant).

I don't have the necessary expertise to have an opinion about the controversy itself, but lots of people who do were skeptical right from the start and the naysayers now hove more ammunition that ever. Note to all: doing science by media is a really, really Bad Idea.

Further reading:

"When It Comes To Being The "Missing Link", Ida -- You Are NOT The Candidate" at Prancing Papio.
"Breaking the Link - Darwinius revealed as ancestor of nothing" at Not Exactly Rocket Science.
"Bone Crunching Debunks ‘First Monkey’ Ida Fossil Hype" at Wired Science.
"Ida Redux" at NeuroLogica.

Call for contributions!

Ionian.Enchantment@gmail.com (Michael Meadon) — Thu, 22 Oct 2009 12:25:00 +0000

So it's almost Carnival of the Africans time again - it'll be back on the 28th, and I'll be your host. Write something, check whether it fits our guidelines and then send it to me at ionian.enchantment@gmail.com. Or preferably, first check the guidelines and then write something. Anyway, DO send me entries!

Oh. And if you'd like to host the carnival, email me too...

Lazy Linking

Ionian.Enchantment@gmail.com (Michael Meadon) — Thu, 22 Oct 2009 07:42:00 +0000

Your (sorta) weekly dose of lazy linking...

"Churches involved in torture, murder of thousands of African children denounced as witches"

A genuinely sickening report on Africa's growing witch craze. It's positively Medieval. And who's at the forefront? Yep, the churches. Religion and evil, who would have thought...

"Facial Profiling: Can you tell if a man is dangerous by the shape of his mug?"

A Slate piece on recent research by Aaron Sell and colleagues on adaptations for the visual assessment of formidability. I have in fact written a lengthy piece on Sell's research and once it's done and dusted, I'll post it here. Physiognomy is making a comeback. (Via Mind Hacks)

"The Pilgrim's Progressiveness: Does going to Mecca make Muslims more moderate?"

A report on very clever research (pdf) that seems to demonstrate that going on the hajj may in fact make Muslims more moderate. Fascinating and surprising. Note: as far as I know, the research has not yet been published, so it's not been peer-reviewed. Buyer beware.

Obituary of Margo Wilson

I was genuinely saddened to hear of Margo Wilson's death. If you haven't heard of her before, go find out. In collaboration with her husband Martin Daly, she produced groundbreaking work on the Cinderella effect and homicide.

"Experimenting on Mechanical Turk"

Using Amazon's Mechanical Turk (in which people get small payments to do simple tasks) to do psychological experiments. Pretty cool, but rather fraught. (Via John Hawks).

"England’s libel laws don’t just gag me, they blindfold you"

An op-ed in The Times by Simon Singh urging reform of libel law. He argues convincingly that England's preposterous libel laws not only limit freedom of expression, it limits people's right to know. A healthy democracy allows open debate and putting the onus on the defendant and not having a public-interest clause stifles such debate. It boggles the mind that these laws survived into the 21st century.

"Refuting this post helps confirm it"

A short but sweet post on Marginal Revolution about why blogging is good for you. Some of the critical comments are worth reading too: it's certainly possible to blog in a echoing chamber.

"Goodbye HuffPost, Hello ScienceBlogs: Science as a Religion that Worships Truth as its God"

David Sloan Wilson's inaugural post at his new home over at ScienceBlogs. Wilson, if you don't know him, is an eminent biologist and one of the leading proponents of neo-group selection. Note: some other dude seems to have posts on the same blog (despite not being listed as an author). Those posts are dumb.

Gene Callahan vs Evolutionary Psychology

Ionian.Enchantment@gmail.com (Michael Meadon) — Mon, 19 Oct 2009 08:14:00 +0000

So I recently had an uncharacteristic (and unpleasant) online altercation with one Gene Callahan about evolutionary psychology and, amazingly, whether Daniel Dennett should be taken seriously. I'm not blogging about this because it is inherently interesting (it's not), but because it nicely illustrates several common misconceptions about applying evolution to psychology and it reminds us that intellectual arrogance is a Bad Thing.

(I’d like to note before proceeding that it’s not as if I’m an uncritical fan of evolutionary psychology. There are, I think, numerous problems in the field, and the standards of evidence is far too often far too low. Some papers in the field are downright embarrassing (this one is the worst I’ve come across) and on my blog I have, among other things, excoriated Satoshi Kanazawa and critiqued Shermer’s application of evolutionary psychology to markets.)

Anyway, the saga in question started when a friend shared a blog post of Callahan’s on Google Reader in which he endorses John Dupré’s Human Nature and the Limits of Science, an uninformed screed against evolutionary thinking in psychology. (See this critique). I won’t have that much to say about the content of Callahan’s post – I will focus on his replies to my comments – but one remark about it is in order. Callahan:

I’ve just been re-reading John Dupre’s wonderful take-down of evolutionary psychology, Human Nature and the Limits of Science. Now, Dupre never disputes the obvious truism that, say, human ethics or religion evolved. But he notes that this is remarkably uninformative, since everything humans do so (sic) evolved, including their ability to write papers on evolutionary psychology!

This is somewhat cryptic and unclear, but straightforwardly interpreted, it is obviously wrong. To see why, consider the following. (I) Phenotypic structures (more precisely, biological processes) are either adaptations or the by-products of adaptations. (II) What distinguishes evolutionary psychology (at least of the Santa Barbara School) from sociobiology is the claim (see Tooby & Cosmides, 1987 [pdf]) that manifest behavior doesn’t evolve, modular information processing systems embedded in brains do. (III) Behavior is the result of a complex interaction between the environment and these information-processing systems; including direct environmental influences (e.g. drugs, brain injury) on the physical substrate of these information-processors. Observed behavior, then, is the product of the environment interacting with information processing mechanisms in the brain, and the brain is constituted of adaptations – structures that exist just because they increased fitness relative to alternatives in evolutionary history, including by producing or facilitating certain behaviors – or the by-products of such adaptations. It is therefore false that ‘everything humans do evolved’ since behaviors themselves don’t evolve, some behaviors result from by-products of evolution (not to mention pathology), and rapidly changing environments (the appearance of development of civilization, say) can interact with evolved psychological traits to produce novel behaviors (including writing papers on evolutionary psychology). The proposition that evolutionary psychology – broadly construed – is uninformative stems from these misunderstandings, and is indistinguishable from the crazy idea that evolutionary thinking generally is uninformative. Moreover, this claim is belied by the fact that we have discovered psychological abilities and traits (e.g., e.g.) that we didn't know about until we thought about human psychology from an evolutionary perspective.

On to the actual altercation… Callahan’s post rather annoyed me, so I left an aggressive – probably too aggressive – comment to the effect that (a) he is unqualified to have an opinion and (b) that he should read Daniel Dennett’s critique of the book. On reflection, I regret making point (a) as baldly as I did: I failed to err on the side of charity and to assume good faith. (Not to mention that I took Wikipedia’s word that he’s an economist, when he self-identifies as a philosopher, though I can’t help pointing out that he has a PhD in neither, so appending “in-training” is appropriate. Note: I don’t have a PhD either, so I happily concede I’m a wannabe cognitive scientist, not the real deal... yet). Understandably, Callahan didn’t take too kindly to my comment, so he replied aggressively himself, and then headed over to my blog and threw insults around on two of my posts: here and here. (Some tangential pedagogy: as I explained at length in my Fun with Fallacies post a while back, there is a difference between the ad hominem logical fallacy and mere insult. Callahan [I think, the comment was anonymous] calling me a “rude little punk”, for example, is not an instance of the ad hominem logical fallacy; even saying ‘you’re wrong and a rude little punk’ wouldn’t be fallacious. Only if he had said (or implied) ‘you’re wrong because you’re a rude little punk’ would he have committed the fallacy. There must be some inference drawn from some purported negative quality for the fallacy to occur, merely alleging someone has a negative quality is not itself fallacious, though of course it may be false or libellous).

Anyway, Callahan’s reaction to (b) was remarkable and illustrative: he dismissed Dennett’s critique of Dupré without reading it because he thinks Dennett’s work is a “rubbish heap”. Here’s what he said:

“Oh, and I’m not going to bother reading his [Dennett's] criticisms of Dupre. If I read several things by someone and they are universally rubbish, I really can’t be bothered to keep going through the rubbish heap. Anyone dull enough to have come up with the ‘brights’ idea really can be dismissed out of hand, don’t you think?”

Wow. The first sentence is the most interesting, but note that the second is factually inaccurate (Dennett endorsed the Brights idea – as did Dawkins – but neither came up with it) and invalid to boot. Worse, the suppressed premise (pdf) that would make the argument valid - ‘anyone who has one really daft idea can be dismissed out of hand (on all topics)’ – is clearly false. Granting for argument’s sake that the Brights idea was daft, it’s simply not true that if someone has one spectacularly bad idea that everything else they say will be wrong. Newton had silly ideas about alchemy and the Bible, but that doesn’t mean we can dismiss the Principia. Linus Pauling obstinately stuck to the incredibly implausible notion that ultra-high doses of Vitamin C can cure cancer, but that doesn't mean his work in chemistry was worthless. Physicists with idiotic philosophical or religious views are a dime a dozen, but that doesn’t mean their work as physicists is necessarily bad. Is it really that surprising that a philosopher and a ethologist, respectively, could be persuaded to endorse a bad marketing idea? If they did so would it mean that their professional work was all worthless?

Callahan’s first point in the above paragraph, though, is far more interesting and so worth looking into in a bit more detail. At first I thought he couldn’t possibly believe it – that perhaps he was just pissed off and said something silly in the heat of the moment – but he failed to back down in subsequent comments, so he really does seem to believe it. In summary, his argument is: ‘I read x% of Dennett’s work, what I read was universally rubbish, therefore everything by Dennett is rubbish’. (Callahan calls Dennett's work 'a rubbish heap', so he's not just making the more reasonable claim that 'he couldn't be bothered to read more of it'). This argument too is invalid - though of course I hardly expect people to make consistently logically valid arguments in blog comments. The point is that it contains at least one false suppressed premise, namely: ‘if I’ve read some proportion of a scholar’s work, I can judge all of it.’ This is both arrogant and false, the latter since for it to be true everyone would have to produce either consistent rubbish or consistent non-rubbish: it implausibly rules out a mixed bag. Newton, again, produced utter nonsense and sublime science, Jared Diamond wrote both Guns, Germs, and Steel (one of the best books of the 90s is my opinion) and Why is Sex Fun? (which was very bad indeed) and so on.

As a rule of thumb, I’d say that unless (1) you have read a good proportion of some scholar’s output, (2) you are qualified to judge all of it, and unless (3) everything you have read is entirely devoid of merit and without any redeeming qualities whatsoever, making a black-and-white inference about an entire corpus of work is just not reasonable. (People who make a priori unlikely claims in conflict with scientific consensus, show no interest in justifying their claims, and who lack relevant expertise can in most cases be dismissed out of hand. Sylvia Brown’s books, for example, are just not worth paying attention to. I take it as obvious that Dennett does not come close to fulfilling these criteria). Given how much Dennett has produced I’m willing to bet Callahan has not satisfied (1), and I have serious doubts about (2) since as far as I know not even Callahan himself claims to be a qualified cognitive scientist or philosopher of mind. More importantly, the prior probability of (3) is preposterously low and Callahan thus has a huge burden of proof to discharge. For him to do so he would not only have to demonstrate (preferably in a mainstream peer-reviewed journal) that, say, Consciousness Explained (CE) and Darwin’s Dangerous Idea (DDI) are rubbish but also explain why so many smart people – whether they agree with Dennett or not – were fooled into concluding the opposite. In other words, he must rigorously justify his initial contention not only that Dennett is wrong, but so wrong that his work is entirely worthless. And, if Dennett’s work is indeed utter rubbish, Callahan must explain why Dennett has been so influential: why, for example, CE has been cited 4700+ times and DDI 3000+ times. (Callahan objected to this point by saying it merely shows Dennett is famous, and mere fame presumably doesn’t track genuine merit. I responded that there’s a distinction between fame and influence: Dennett is both, Paris Hilton is only the former, Frege (say) is only the latter, and both Callahan and I are neither. Scholars just don’t see the need to read, let alone refer or respond to, utter rubbish so either Callahan is wrong or thousands of highly trained and really intelligent people are deluded. Of course, Callahan could be right, but I wouldn't recommend betting on it).

The moral of the preceding analysis, I think, is that intellectual arrogance is a very Bad Thing. I admit that I’m not exactly diffident, and that I have regularly fallen afoul of the principles I outline below. But I’m not nearly arrogant enough to dismiss whole disciples or declare all of an influential and prolific academic’s work utter rubbish. The common cause of such extreme beliefs, it seems to me, is overweening intellectual self-confidence, which is in turn arguably a product of an insufficient familiarity with one’s own fallibility. Cognitive biases and illusions are universal and ineradicable, the world is incredibly complicated and you can know only a fraction of the currently knowable. The mark of someone familiar with the above is scepticism, suspicion of bald assertions and hasty generalization, doubt, caution, a willingness to reconsider and admit error, and being scrupulously careful with facts and arguments. Callahan, it seems to me, fails to live up to these principles and the result is beliefs that, frankly, are downright idiotic. Or, as I put it rather more colorfully in my comments on his post, if these really are his beliefs, he should STFU, GTFO and take his FAIL with him. Srsly.

Of course, I could be wrong. Maybe I've been blinded by emotion, maybe I've been unfair, maybe I've misunderstood. If so, show me I'm wrong and I'll reconsider. Really.

Skeptics' Circle #120 and #121

Ionian.Enchantment@gmail.com (Michael Meadon) — Sun, 18 Oct 2009 15:19:00 +0000

The 120th edition of the Skeptics' Circle is out at Pro-Science; it also features a nice discussion of the history of the carnival. Anyway, posts to check out: The Bronze Blog on how to deal with trolls and other annoyances, and Unleashed (part of the ABC stable of blogs) on the silliness of homeopathy. My post "Fun with a local homeopath" was included.

The 121st edition of the Skeptics' Circle is out at The Mad Skeptic. Have a look at: Effort Sisyphus on the goings-on at the NECSS conference (which was hosted by the NESS and NY Skeptics), Podblack Cat on the process of skeptical blogging (and what skepfails to avoid), and The Examining Room of Dr. Charles account of visiting a Darwin exhibit.

Encephalon #76

Ionian.Enchantment@gmail.com (Michael Meadon) — Sun, 18 Oct 2009 15:14:00 +0000

The 76th edition of Encephalon is out over at Neuroskeptic. Posts to check out: The Neurocritic asks whether neuroscience tells us torture doesn't work, Neurophilosophy on how vegetative and minimally conscious pantiens can learn, and Crime and Consequences on the silliness of neurolaw.

Public Service Announcement: You have an immune system

Ionian.Enchantment@gmail.com (Michael Meadon) — Sat, 17 Oct 2009 12:49:00 +0000

As some of you might know: you have an immune system. In fact, you have an adaptive, extraordinarily intricate and complex immune system that evolved over hundreds of millions of years because there are innumerable tiny predators (bacteria, viruses, etc.) that, in effect, want to eat you. And, as anyone with immunodeficiency (whether innate or acquired) can attest, the immune system is almost always effective and, without it, you'd be in serious trouble. Even people with functional immune systems do get sick, of course, and this happens for several reasons, including that it just needs time to adapt (by evolving responses to novel infections) or because the system simply can't deal with the infection.

Why bring this up? Doesn't everybody know this? Well, I'd hope so, but many people effectively deny that they have an immune system when they claim something along the lines of 'I took medicine X, I got better, therefore I got better because I took medicine X'. My point is just this: you simply can't know whether you got better because of your immune system or because of X. Your immune system is really good at it's job - not perfect, of course, but damn good (see immunodeficiency again). And since it's adaptive - in a quite literal sense it evolves ways to deal with new infections - when you get sick and then better, it might be because you took medicine or because your immune system found an effective response (or both, or neither). But in an individual case you simply can't know. Concluding you got better just because of taking medicine - i.e. saying without taking it you wouldn't have gotten better - is an instance of the post hoc ergo propter hoc logical fallacy. That is, you're saying just because Z happened after X, it must be the case that X caused Z to happen. But of course this doesn't follow: Z (getting better) might have nothing to do with X (taking medicine) because X could just have been incidental, the real cause of Z might have been P (your immune system) or Q (the placebo effect) or something different. In general, the only - and I do mean only - way to decide in a rational way whether some treatment is effective or not is to do science: that is, do a properly designed, large-scale, double-blind randomized clinical controlled-trail.

Saying you got better just because sometime earlier you had taken medicine, then, is in effect to deny you have an immune system. Which is dumb. Take home message: (1) Thou shalt not rely on anecdotal evidence and (2) Thou shalt rely on evidence-based medicine (or, better yet, a variant known as science-based medicine).

Video: Eyes on the Skies

Ionian.Enchantment@gmail.com (Michael Meadon) — Fri, 16 Oct 2009 13:21:00 +0000

There is more science to celebrate in 2009 than just anniversaries relating to Charles Darwin, 2009 is also the International Year of Astronomy. (Because it's the 400th anniversary of the first astronomical observations with a telescope). Anyway, since my fiancée is such an astronomy nut, I downloaded "Eyes in the Skies" for her, the freely-available official documentary of the IYA. (Alas, they don't have a single file for download, so you have to download 7 separate 'chapters')

My verdict: watch it. While it's not quite professionally produced, and while there is weird and annoying pronunciation throughout (e.g. NAzzzA for NASA), the actual content is great. It's basically a primer on the history of telescopes - not just optical, ones that observe all parts of the electromagnetic spectrum - and, most interestingly, it covers future telescopes that are being built or that are on the drawing board.

(Hopefully South Africa will win the bid for the Square Kilometer Array. That would be awesome).

Lazy Linking

Ionian.Enchantment@gmail.com (Michael Meadon) — Fri, 16 Oct 2009 12:13:00 +0000

"The Durban Boredom Festival"

So a friend, my fiancée and I went to a local psychic fair recently. I was planning to write about it... but it was a horrid experience, so I never got round it it. Luckily, Angela (the aforementioned fiancée) has written a great account of what went down at the fair and trust me, short as it is, her post contains everything you'll possibly want to know about it. Overall conclusion: way too much incense, rampant woo, boring as hell, complete ripoff.

"The latest verdict on using brain imaging for lie detection"

BPS Research Digest reports on using fMRI et. al. to spot lying. Short version: it doesn't work. (At least not yet).

"Offensive Play: How different are dogfighting and football?"

Malcolm Gladwell's latest New Yorker piece in which he compares the morality of dogfighting - almost universally reviled - with that of American football. It turns out that, like with boxing, a football career often results in an Alzheimers-like condition called chronic traumatic encephalopathy. Amazingly, new resarch using accelerometers has revealed players regularly suffer hits to the head of up to 90gs. Not surprisingly this is a Bad Thing that does severe damage to the brain over the long run. Gladwell suggests this may make football morally comparable to dogfighting: the injuries and suffering of the players are an inherent and ineradicable feature of the game.
As a big rugby fan I couldn't help wondering what the situation is like for my favorite Saturday diversion. Do rugby players also suffer as much damage? Obviously, only research could settle the issue (and some may already exist, I don't know). From the armchair, it's difficult to tell: on the one hand, there are many fewer hits to the head in rugby but, on the other, the players don't wear helmets or much protective gear. My (rather bland) guess, for the little that's worth, is that brain trauma is not as common in rugby as it is in football or boxing, but significantly more prevalent than in the general populace. I'm not going to stop watching though, that's for sure.

"Psychology: A Reality Check" (paywall, I think)

A great Nature editorial calling for evidence-based clinical psychology in the United States. I'd say it's also much needed elsewhere, the training of psychologists is often criminally devoid of science or even critical thinking.
"Clinical psychology at least has its roots in experimentation, but it is drifting away from science. Concerns about cost–benefit issues are growing, especially in the United States. According to a damning report [pdf] published last week an alarmingly high proportion of practitioners consider scientific evidence to be less important than their personal — that is, subjective — clinical experience."
"The irony is that, during the past 20 years, science has made great strides in directions that could support clinical psychology — in neuroimaging, for example, as well as molecular and behavioural genetics, and cognitive neuroscience. Numerous psychological interventions have been proved to be both effective and relatively cheap. Yet many psychologists continue to use unproven therapies that have no clear outcome measures — including, in extreme cases, such highly suspect regimens as 'dolphin-assisted therapy'."

"How We Lost Our Diversity"

Interesting piece by the excellent Ann Gibbons about new research on the causes of human genetic homogeneity (relative to other primates).
"Modern humans are a lot alike - at least at the genetic level - compared with other primates. If you compare any two people from far-flung corners of the globe, their genomes will be much more similar than those of any pair of chimpanzees, gorillas, or other apes from different populations. Now, evolutionary geneticists have shown that our ancestors lost much of their genetic diversity in two dramatic bottlenecks that sharply squeezed down the population of modern humans as they moved out of Africa between 60,000 and 50,000 years ago."
See also: John Hawks' fairly critical analysis of the same study.

"Analogies to apes lead us on the wrong track"

Razib Khan over at Gene Expression on how Ardi drives home the message that drawing analogies between humans and the other extant apes can be misleading. Six million years is a long time, and there's no reason to think our common ancestor with the chimps and bonobos was particularly chimp-like. Somewhat counterintuitively, the opposite might even be true.

"Dear Penn and Teller: Bullshit!"

I've only recently remembered that I have Season 6 of Penn & Teller's Bullshit so I'm only watching it now. And like Massimo Pigliucci in the above post, I just hated their episode (6-06) on environmentalism. Libertarians so obviously have blinkers on when it comes to global warming that it positively amazes me that they're not more self-critical. It also reminds us all, of course, that being vigilant about our own biases is important.

"Islam: A Shifting Focus"

One of the most widespread misconceptions about Islam is that most of its faithful are Arabs. In actual fact, Asian Muslims vastly outnumber Muslims from other parts of the world, making up 61.9% of the global number of 1.57 billion believers.
"A new survey of the world’s Muslim population, by the Pew Research Center based in Washington, DC, will help those who are keen to break that link [i.e. the perception that most Muslims are Arabs]. It estimates the total number of Muslims in the world at 1.57 billion, or about 23% of a global population of 6.8 billion. Almost two-thirds of Muslims live in Asia, with Indonesia providing the biggest contingent (203m), followed by Pakistan (174m) and India (160m)."
"Perhaps more surprising will be the finding that the European country with the highest Muslim population is not France or Germany, but Russia, where 16.5m adherents of Islam make up nearly 12% of the total national population. Compared with other surveys, the report gives a lowish estimate for the number of Muslims in France (3.6m), as it does for the United States (2.5m); in both those countries, secular principles make it impossible to ask religious questions on a census."

Carnival of Evolution 16

A superb edition of the Carnival of Evolution - there are many worthwhile posts to check out. My pieces on foxes and on chameleons were featured.