Science and the Zodiac – a brief introduction to an epistemological placebo

It is somewhat of a cheap shot for a scientist to come down harshly on astrology. As a matter of fact, it is probably the lowest hanging fruit there is.

An easy target

Nevertheless, the undying popularity of astrology in general and horoscopes in particular cannot be denied. Most newspapers in most countries won’t do without a horoscope page. Most can do without a science and technology page. This is not a conspiracy. Generally speaking, the media aims to please – it will give people whatever they want to read or hear (in order to survive against its competition, until a stable state is reached). This should tell us something about the relative popularity of these topics in the general population. Of course, most hardcore scientists take this only as further evidence that the mass of men are – at best – stupid sheep and that their opinions can be dismissed out of hand. There might be something to that, but it does not take away from the fact that the continuing popularity of astrology – not to be confused with astronomy – is a fascinating phenomenon in its own right. As a matter of fact, this has fascinated me at least since high-school. Incredulous at the fact that one of my friends was looking up her horoscope, I asked her why she believes this stuff in this day and age. The response was as pragmatic as it was telling: “Oh, I only believe it, if it is good!” Recently, it was pointed out that due to the precession of the axis of the Earth, the ancient star signs are no longer in alignment with their current positions. In other words, the dates of the star signs of the Zodiac, familiar to all have to be adjusted. In addition, a new sign – Ophiuchus was introduced. Outrage predictably followed. Of course, this whole affair shows just how preposterous the whole notion of zodiac signs and zodiac based horoscopes really is. Axial precession is a phenomenon that did not just happen yesterday. It has been continuously going on for millions of years, including the couple of thousand years since the introduction of the Zodiac system. The value of these personality characterizations and predictions of the future can adequately be assessed by the fact that the fundamental misalignment was never noticed. Of course, this makes a perfect foil for people who always noticed some slight inaccuracies, but let’s be serious. Obviously, there is nothing to horoscopes. More on this later. But how could the people who came up with this stuff be so wrong? What were they thinking? Contrary to popular belief, people are not stupid. At least those who advance civilization by creating culture typically aren’t (as controversial as the zodiac might be, it is a cultural achievement; let’s be fair). How is this possible? Historically speaking, this is actually a quite common or even typical phenomenon: Something that once made sense in the original context of discovery/creation no longer makes sense in the context of justification. Between initial discovery and the current need for justification, millenia have passed. During this time, civilization has accumulated a lot more knowledge. In other words, the caravan of culture has moved on. This happens all the time. It is called progress. Note that if astrology and horoscopes didn’t already exist, it is very unlikely that – given what we know about the nature of stars, incomplete as our knowledge might be – we would introduce such a system today. So how and why did it come about way back when? Because it made sense. Carefully watching the sky – as the ancients are known to have done – can reveal a tremendous amount of real information about issues of tremendous importance to the civilization. For instance, observing an equinox allows a civilization to decide when to harvest and when to plant. This is absolutely crucial information for an agrarian society. Similarly, as the motion of heavenly bodies is closely tied to the progression of time, watching lights in the sky can provide quite a bit of information about the general kind of weather (e.g. storms, snow) one is likely to encounter. Moreover, the annual recurrence of the seasons and the close watch thereof some amount of Planungssicherheit to early societies. The progression of lights in the sky seemed even to directly influence events on earth, such as the tides and their relation to lunar cycles. In other words, the sky abounds with information, and ancient cultures spend tremendous efforts extracting it systematically, which led to the creation of calendars, etc. From this, it is a very short leap to astrology. In a world largely untouched by scientific knowledge, a world shrouded in mysticism, a world in which the night sky loomed much brighter than today (due to the lack of electric illumination), it might not be a leap at all. On the contrary. Given all the demonstrably useful information about the future that the sky does hold, the burden of proof that the sky does not hold more personally relevant information about the future might be on the skeptic (in the ancient world). As a matter of fact, it might have been tempting to link the constellations of the smaller night lights to personal matters, in contrast to the motions of the brighter and larger lights, which determine the future of the entire society. Also remember that there was plenty of time for the ancients to ponder these matters, in the absence of any electronic night entertainment whatsoever. Given what we know about human perception, it is no surprise that they were able to recognize patterns in the starry arrangements of the night sky.

The classical zodiac. Can you spot your sign?

Humans typically have a desperate desire to reduce uncertainty. Of course, the future introduces a tremendous amount of uncertainty. Hindsight is famously 20/20, whereas foresight is far from it. The insidious thing about the nature of reality is that decisions have to be made in the present – under uncertainty, whereas the consequences of these decisions occur in the future. Once the future reveals the outcome of the decision, there is no way to go back and change it, however desirable. Obviously, this is unacceptable and terribly unfair. Contemplating these matters, the desire to predict the future from things we can observe right now becomes overpowering. And so, Astrology is born. Of course, nothing changed about the nature of reality, nor the human desire to know the future since those days. And so, it lives on. It it can reduce the uncertainty even a little bit, it seems worth doing. Now, make no mistake. There is absolutely zero empirical evidence in favor of astrology or horoscopes. Nothing, nada, null. Conversely, there is plenty of positive evidence showing that it actually does not work. In scientific terms, this is a closed case. Open and shut. No ambiguity about it. If anything, the situation is eerily similar to homeopathy, which works by the power of the placebo effect. Thus, from now on, I will refer to astrology and horoscopes as an “epistemological placebo“. Reviewing the empirical evidence that astrology and horoscopes are really just instantiations of an epistemological analogue to a placebo effect would require a book-length contribution. That won’t and can’t happen today. Luckily, that is not necessary. A sampler will do. a) Horoscopes “work” (insofar as a sizable proportion of people feel themselves adequately described) because of Barnum statements. These are so general in their characteristics and so vague in their predictions that they could essentially fit anyone and anything. The remarkable thing is that people still believe that they apply specifically to them, particularly if the purported characteristics or events are positive. The psychological literature clearly shows that horoscopes work via Barnum statements, even across cultures. On another note, there is also no internal consistency. This is something you can try at home. Get 10 different horoscopes from 10 different newspapers for a given day and see if there is any overlap that goes beyond that expected by chance. Actually, this has now been done. Given the empirical evidence there is no merit in belaboring this point. To be perfectly clear, the situation truly is remarkable. To use an analogy: If people come to me throughout the day and ask me for the time and I always tell them the exact same time, and they always believe me. That is what it means to believe in astrology. This suggests the feedback mechanism is broken in those who do believe. Presumably, the want to believe overrides the feedback from reality, which is often more ambiguous as simply knowing what time it actually is. b) There is no plausible mechanism. I will make this one short. Even if one is generous, no known or conceivable mechanism exists that could explain why a particular constellation of heavenly bodies at the time of birth matters. And none has been put forward. That is only consistent. Any that is put forward will be shot down quickly. One example: Gravity. Even if one is generous, the gravitational force of the people in the room at birth is substantially larger than that of most distant heavenly bodies. Unless we live in a completely mystical universe, this one is a tough nut to crack for astrologists. The fact that science works, that nature is lawful, is evidence enough (for me) that we do not live in that place. c) Personality psychologists have worked hard, with sophisticated statistical methods, for a long period of time to quantitatively characterize the similarities and dissimilarities of people. What we came up with so far is different “inventories” with reliabilities and validities of varying respectability. It is a tough problem. This is not surprising. The brain is complex and is known to generate behavior that is not necessarily consistent in various temporal and situational contexts. What we did not find was that people could be classified in 12 (or 13) distinct categories so that the characteristics are distinct between categories but exhibit low variance within a category. Such a simple scheme is alluring, but none ever worked. People are just not that simple. It is preposterous to suggest – despite every evidence to the contrary – that they are. To be sure, timing of birth within the year does have an impact on personality and behavior (e.g. likelihood and method of suicide). There is no question about that. But there are many good reasons for these effects, none of which have to do with astrology: Amount of sunlight in the first life months, levels and type of airborne pollen, temperature, general mood, and so on. There is also a tremendous amount of artificial categorization which is imposed by society itself, which can have a considerable influence on personal future behavior. School enrollment cutoffs are typically between June and September (depending on the locality). For instance, it has been shown that – due to the fact that grouping kids by cohorts that span one year gives some that are among the oldest a considerable developmental advantage. This has been named the relative age effect or birth date effect. The final outcomes are dramatic: Elite athletes are much more likely to have birthdays in the first half of the year. Similar effects have been reported for intellectual outcomes. In short, there is absolutely no need to invoke mystical forces, however appealing, to account for such effects. So why do some people still believe this, even if there is not a shred of evidence in favor of it? I don’t think ignorance can account for everything. Motivational components have to be considered. To be sure, motives might differ. Some people might personally and financially profit from astrology. That is a pretty mighty motive. Others might be comforted by sharing beliefs in something that has been believed by many people for very long, a kind of cultural bedrock. The rest? Probably because they really, really want to. And it doesn’t seem to cost much. On the surface of it. But there is hope. I think that if anything, the “new” zodiac system will weaken some dearly held beliefs about astrology. After all, I’m no Pisces, come on now…

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8 Responses to Science and the Zodiac – a brief introduction to an epistemological placebo

  1. rs says:

    Alright, I’m generally sceptic. I don’t believe in God, I don’t believe in souls, reincarnation, magic or other supernatural stuff. Before accepting something as being “very likely true”, my brain is looking for factual explanations or if these are difficult to obtain, at least it tries to come up with an intuitive cohesiveness without obviously violating logic.

    For various reasons all daily (or weekly, monthly, …) horoscopes are obviously nonsense. But I’m really not interested in those.

    I’m interested in why I perceive the character traits that Zodiac signs assign to people to be mostly accurate.

    Let’s first lay some groundwork.

    AFAIK there is one set of character traits for each member of Zodiac signs. Astrological scripture generally agrees on this set for each sign. So for example, being “shy” and “introverted” are two of the more typical character traits assigned to people associated with the Zodiac sign Cancer. You will find these traits in nearly every text that describes the character traits of Cancer. In contrast you will find a trait like “extroverted” when Libra is described. These adjectives seem to be very specific (not vague like horoscopes) — specific enough to allow clear distinction between two such sets (although some sets do occasionally overlap). So one can say that there are closed, relatively distinct sets of character traits for each of the Zodiac signs that are generally agreed upon and don’t change. In other words, each Zodia sign unambiguously encodes a fixed set of character traits.

    It seems very plausible and likely to me that character traits are a result of DNA and environmental interaction, very much like for example “hobbies” or musical taste. Character traits seem to be pretty much pre-determined by DNA, but have a certain degree of flexibility, depending on the actual environmental interaction. (This is for example unlike eye-color, which solely depends on DNA.)
    The degree of this flexibility however is limited. So a person that is generally introverted, doesn’t just become extroverted the next day and goes back to being introverted the day after that. Temporary differences in mood are natural, but a character trait is more like a long time average. Once fully developed, these don’t change much the rest of your life — or at least they don’t change to a degree that would make it impossible for a person to identify the character traits of another person. So in other words, individual character traits are also pretty clear, and not vague or randomly changing.

    Now to come back to my question. Why do I perceive Zodiac signs to be accurate for (guess) about 70% of the people I know good enough to characterize?

    As explained above, neither the trait sets defined by each of the Zodiac signs, nor the individual character traits of a specific person, are particularly vague. They are pretty clear. There seems to be some “vagueness” in both cases, but is this vagueness enough to explain the perceived accurateness with the Barnum Effect?

    Couldn’t the accurateness of the signs be because of some other reason that is not yet understood? I guess that’s the real question I was trying to get to.
    Could there be any validity to the Zodiac signs and the character traits they encode? Where the traits just picked at random? Or did were they discovered over time, because of some underlying rule or pattern, that makes a particular set of traits very likely for a particular date of birth (or impregnation)?

    I do believe that there exists the possibility that there is some unknown and probably complex cyclic interaction (between Earth, Moon, and whatever the heck other radiation, gravitation, …) that influences molecules and DNA in a some way that makes certain character traits likely.
    I think it would be silly to reject the possibility of such an interaction, unless it is proven that it would be in violation with logical facts.

    Maybe that’s the reason why people still think there might be something to it. The intuitive feeling that it is possibly true may keep it alive. At least for me it does.

    - rs

  2. Lascap says:

    First of all, thanks for distinguishing Zodiac signs characterizing people from predictive horoscopes. They are closely linked, yet separate. I was thinking about making a point about this in the post itself, but it was getting way too long.
    Second, it is indeed important to keep an open mind as a scientist. This is lost on some, but science is – by the very nature of the enterprise – inherently an unfinished business. Always a work in progress. One never knows which future advance will overturn conceptions that were dearly held in the past.
    Finally, it is true that it is not necessarily crippling that no mechanism has been established so far. We don’t know everything.
    The last point deserves clarification. While it is not necessary to show a mechanism, there needs to be an established effect (something to be explained). Common sense suggests that it is extremely hard to prove a negative. Few realize this, but contemporary theory (and practice) of science make it impossible to do so. Thus, the onus is on those who want to show that there is something to be explained. Given the specificity of the predictions, and the subjective strength of the relationship, this should not be hard. However, to my knowledge, no one was able to do this in the history of science, despite tremendous interest to do so. Conversely, as I alluded to in the post, several studies failed to establish this. There is no question that there are seasonal trends which vary the incidence of schizophrenia, suicide, etc., but none of that matches up with the Zodiac signs. Also, the very fact that most of the population had the “wrong” sign without noticing is strong evidence that there is nothing to be explained here. Thus, unless forced by the evidence to reconsider, I chalk this up to man’s search for meaning.

  3. rs says:

    Yes, seasonal trends that are result of earthly phenomena (as you mentioned in your initial post) seem to be far more likely to be responsible for certain character traits than some weird artificial reasoning that is based on the alignment of distant stars. So one could assume that there is indeed some underlying mechanism that influences character traits, which is however linked to regional happenings on earth — and not so much caused by “astrology”. This makes perfect sense to me.
    It is clear though, that the earth isn’t somehow seperated from other heavenly objects. For example, seasons exist because of the interaction of earth and sun. So the times when climate, vegetation and animal life influences human behaviour are directly aligned with the mechanics of earth and sun (and moon, and to a lesser degree all other stars and planets that interact in some way).

    In this sense it seems possible that Zodiac signs correctly encode character traits “by accident”. The causes are not correctly identified, but the effects are.

    Also if this were true, one could expect clear regional differences in astrology. Character traits linked to a certain date of birth in India shouldn’t be the same they are for a certain date of birth in Norway, for example.

    The fact that most of the population had the “wrong” sign without noticing doesn’t mean that there is nothing to be explained. I think it does quite the opposite. It supports the possibility that the date of birth and the regional and seasonal implications weigh far more than the movement of distant stars — and it leaves room for the possibility that character traits are indeed linked to dates.

    - rs

  4. Lascap says:

    It sounds like we are not necessarily in disagreement.

  5. rs says:

    I know. I didn’t try to disagree. I was hoping for further enlightenment.

    And I think I got that.

  6. Lascap says:

    It is quite possible that this is an instantiation of what psychologists call a “fundamental attribution error”. Essentially, people picked up on seasonal variations in character traits, as these effects are (possibly) quite strong. However, factors that are actually causal are invariably quite subtle and not easily measurable at the time (e.g. temperature, light/Vitamin D levels and so on). However, the position of the stars is quite salient (and closely linked to seasons). Thus, it would not be surprising if the ancient mind linked the traits to the stars (which made quite a bit of sense, given the ancient worldview), as opposed to the actual causes.

  7. rs says:

    Exactly. That’s a more sophisticated explanation of what I meant with “by accident”. And I wouldn’t be surprised if this in the end actually turns out to be the truth. Like I said, it would also explain why the “new” sign doesn’t actually matter.

  8. decora says:

    if it is a placebo; we know that placebos work in some cases.

    a recent study showed, iirc, that placebos work –even if you know its a placebo–.

    consider the ‘science and technology’ section of a paper. often what are they filled with? ‘scientists just figured out that butter is bad for you. use margarine instead’

    a year or two later

    ‘scientists just figured out margarine is bad for you, use butter instead’

    a year or two after that

    ‘margarine may not be as bad as you think, scientists discover’

    in fact, much ‘science’ has been reduced to the state (in popular culture) where it is no more consistent in its practical advice than astrology. and what does astrology provide? practical advice, not on butter or margarine, but on , you know, like “try to be gentle in your interactions today”, “be careful of too much stress”, “try not to get yourself into any fights this month”, etc etc etc.

    are there scam artists in astrology out for money? yes… guess what, there are also the same things in science. we have had many scandals in science journals regarding ghostwriting, corporations paying for results, doctors being pressured by drug companies, and even an entire sham journal made up just by a company to push its products.

    for an ordinary person, astrology might seem no more or less illogcal and ridiculous than anything else that bevies of ‘experts’ are rushing to tell them every day. in 2005-2006 it was ‘buy a house, refinance your mortgage, take the equity and go on vacation’. these were representatives from the nations leading financial institutions, people with degrees from harvard, yale, etc, in charge of this stuff.

    in a crazy world, only crazy people can survive.

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